In this chapter we will deal with “mechanizing” induction, i.e. with ways in which theoretical computer science approaches inductive generalization. In the field of Machine Learning, algorithms for induction are developed. Depending on the form of the available data, the nature of these algorithms may be very different. Some of them combine geometric and statistical ideas, while others use classical reasoning based on logical formalism. However, we are not so much interested in the algorithms themselves, but more on the philosophical (...) and theoretical foundations they share. Thus in the first of two parts, we will examine different approaches and inductive assumptions in two particular learning settings. While many machine learning algorithms work well on a lot of tasks, the interpretation of the learned hypothesis is often difficult. Thus, while e.g. an algorithm surprisingly is able to determine the gender of the author of a given text with about 80 percent accuracy [Argamon and Shimoni, 2003], for a human it takes some extra effort to understand on the basis of which criteria the algorithm is able to do so. With that respect the advantage of approaches using logic are obvious: If the output hypothesis is a formula of predicate logic, it is easy to interpret. However, if decision trees or algorithms from the area of inductive logic programming are based purely on classical logic, they suffer from the fact that most universal statements do not hold for exceptional cases, and classical logic does not offer any convenient way of representing statements which are meant to hold in the “normal case”. Thus, in the second part we will focus on approaches for Nonmonotonic Reasoning that try to handle this problem. Both Machine Learning and Nonmonotonic Reasoning have been anticipated partially by work in philosophy of science and philosophical logic. At the same time, recent developments in theoretical computer science are expected to trig- ger further progress in philosophical theories of inference, confirmation, theory revision, learning, and the semantic and pragmatics of conditionals. We hope this survey will contribute to this kind of progress by building bridges between computational, logical, and philosophical accounts of induction. (shrink)

Several studies (e.g., Becklen & Cervone, 1983; Mack & Rock, 1998; Neisser & Becklen, 1975) have found that observers attending to a particular object or event often fail to report the presence of unexpected items. This has been interpreted as inattentional blindness (IB), a failure to see unattended items (Mack & Rock, 1998). Meanwhile, other studies (e.g., Pashler, 1988; Phillips, 1974; Rensink et al., 1997; Simons, 1996) have found that observers often fail to report the presence of large changes in (...) a display when these changes occur simultaneously with a transient such as an eye movement or flash of the display. This has been interpreted as change blindness (CB), a failure to see unattended changes (Rensink et al., 1997). In both cases there is a striking failure to report an object or event that would be quite visible under other circumstances. And in both cases there is a widespread (although not universal) belief that the underlying cause has to do with the absence of attention. The question then arises as to how these effects might be related. Is CB the same thing as IB? If not, what is the relation between them? And given that these phenomena deal with failures of subjective perception, what can they teach us about the nature of our visual experience? In particular, what can they teach us about the role played by visual attention? (shrink)

We present a rigorous way to evaluate the visual perception of correlation in scatterplots, based on classical psychophysical methods originally developed for simple properties such as brightness. Although scatterplots are graphically complex, the quantity they convey is relatively simple. As such, it may be possible to assess the perception of correlation in a similar way. Scatterplots were each of 5.0 extent, containing 100 points with a bivariate normal distribution. Means were 0.5 of the range of the points, and standard deviations (...) 0.2 of this range. Precision was determined via an adaptive algorithm to find the just noticeable differences (jnds) in correlation, i.e., the difference between two side-by-side scatterplots that could be discriminated 75% of the time. Accuracy was measured by direct estimation, using reference scatterplots with fixed upper and lower values, with a test scatterplot adjusted so that its correlation appeared to be halfway between these. This process was recursively applied to yield several further estimates. Results of the discrimination tests show jnd(r) = k (1/b – r), where r is the Pearson correlation, and parameters 0 < k, b < 1. Integration yields a subjective estimate of correlation g(r) = ln(1 – br) / ln(1– b). The values of b found via discrimination closely match those found via direct estimation. As such, it appears that the perception of correlation in a scatterplot is completely described by two related performance curves, specified by two easily-measured parameters. (shrink)

I consider what prima facie attractive communitarian ethical perspectives salient among indigenous African peoples entail for distributive justice within a state, and I argue that they support a form of economic egalitarianism that differs in several important ways from varieties common in contemporary Anglo-American political philosophy. In particular, the sort of economic egalitarianism I advance rivals not only luck-oriented variants from the likes of Ronald Dworkin, G. A. Cohen and theorists inspired by them such as Richard Arneson, Carl Knight (...) and Nir Eyal, but also more ‘social’ kinds advocated by Elizabeth Anderson, Samuel Scheffler and Jonathan Wolff. Although I do not argue that these broadly Kantian egalitarianisms are less plausible than the Afro-communitarian version, I do aim to establish that it should be taken as seriously as they, at this stage of the debate. (shrink)

DESENVOLVIMENTO EMBRIONÁRIO E DIFERENCIAÇÃO SEXUAL -/- E. I. C. da Silva Departamento de Agropecuária – IFPE Campus Belo Jardim Departamento de Zootecnia – UFRPE sede -/- 1.1 INTRODUÇÃO O sexo foi definido como a soma das diferenças morfológicas, fisiológicas e psicológicas que distinguem o macho da fêmea permitindo a reprodução sexual e assegurando a continuidade das espécies. Os processos de diferenciação sexual são realizados durante o desenvolvimento embrionário, onde ocorre a proliferação, diferenciação e maturação das células germinativas e primordiais, precursoras (...) de ovócitos e espermatozoides em fêmeas e machos, respectivamente. Assim, os embriões machos e fêmeas iniciam o seu desenvolvimento de forma semelhante, de modo que em ambos os sexos se estabelecem em estruturas idênticas a partir das quais se formarão os órgãos reprodutores correspondentes a cada sexo. O conhecimento da origem e do desenvolvimento do aparelho genital é indispensável para entender sua função e as alterações que produzem infertilidade ou esterilidade. 1.2 DETERMINAÇÃO DO SEXO CROMOSSÔMICO Nos mamíferos, o sexo cromossômico é determinado no momento da fertilização, quando um óvulo, que contém um cromossomo X, é fecundado por um espermatozoide portador de um cromossomo X ou um cromossomo Y. No primeiro caso, o complemento cromossômico seria XX, o que originaria uma fêmea (sexo homogamético), e no segundo daria como resultado um macho com a fórmula cromossômica XY (sexo heterogâmico). 1.3 A GÔNADA INDIFERENCIADA A primeira manifestação das gônadas se aprecia no embrião em forma de um par de eminências longitudinais chamadas cristas ou dobras gonodais, situadas em ambos os lados da linha média entre os mesonefros (rins em desenvolvimento) e do mesentério dorsal. Nos embriões dos mamíferos, as células germinativas primordiais (CGP) manifestam-se em estágios precoces do desenvolvimento, podendo ser detectadas pela primeira vez na metade da gastrulação. As CGP são células grandes, de citoplasma claro e núcleo grande e redondo, localizadas na parede do saco vitelino, perto do alantoide. Essas células possuem grande capacidade de proliferação e vão migrar desde o endoderma do intestino e o epitélio do saco vitelino, através do mesentério, até as cristas gonodais. Isso ocorre por volta do 26° dia da gestação no bovino. Sua migração realiza-se graças aos movimentos de translocação passiva e deslocamento ameboide ativo. Desconhece-se o mecanismo pelo qual estas células são dirigidas para as cristas gonodais, porém foram estudadas algumas moléculas que se expressam durante sua migração e que poderiam desempenhar um papel importante na diferenciação deste tipo celular. A fosfatase alcalina é uma enzima que tem sido usada como marcador de CGP para determinar a sua origem e migração. Num estudo recente, foi inserido um marcador fluorescente que se exprime unicamente nas células germinativas primordiais de embriões transgênicos, e utilizando este marcador e a fosfatase alcalina determinou-se a origem e o padrão de migração destas células. O primeiro sinal de diferenciação das células germinativas primordiais é a expressão de fosfatase alcalina, e esta apareceu pela primeira vez na parte mais posterior da linha primitiva. No sétimo dia de desenvolvimento no embrião do camundongo, o endoderma visceral (AF+) é substituído pelo endoderma definitivo (AF-) originado na parte anterior da linha primitiva. O fator de transcrição Oct-4 é expresso nas CGP de ambos os sexos, pelo que acredita-se estar envolvido na mantença a totipotêncialidade das células. O receptor tirosina quinase, cujo ligante é o fator de Steel, é outra das moléculas que expressam as CGP. Tem sido demonstrado que este receptor possui um papel muito importante na sobrevivência deste tipo celular. Existem outros fatores que promovem a sobrevivência e/ou proliferação de CGP in vitro. Em experiências realizadas com o fator de transformação beta I (TGFβ-I), observou-se que este tem um efeito negativo sobre a proliferação das CGP. Outra atividade que tem sido postulada a este fator é o de um agente quimioatraente que possivelmente possa direcionar a migração destas células para a gônada. a) Um formado pelas células germinativas primordiais (precursoras dos gametas masculinos ou femininos), rodeadas de células somáticas das quais posteriormente se derivarão as células de Sertoli no macho e as células da granulosa na fêmea. b) O tecido que formará o estroma da gônada: tecido conjuntivo, vasos sanguíneos e as células intersticiais com atividade esteroidogênica (células de Leydig no testículo e a teca interna do ovário). As células somáticas do primórdio gonodal originam-se do mesoderma. Inicialmente são de três tipos: mesenquimáticas, mesoteliais e endoteliais. As células mesenquimáticas e mesoteliais iniciam grande atividade proliferativa ao chegar as CGP. Observa-se então uma condensação de células de origem mesotelial e mesenquimatoso que forma um agregado compacto denominado "blastema gonodal". A partir deste primórdio embrionário, diferenciam-se dois tecidos gonodais: os cordões sexuais e o estroma. Os cordões sexuais são arranjos epiteliais que se encontram delimitados por uma folha basal, e dentro deles encontramos as CGP. Por sua vez, no estroma encontram-se células do tipo mesenquimático e vasos sanguíneos. Neste momento, as gônadas são indiferenciadas e bipotencialmente sexuais, sendo impossível diferenciar, morfologicamente, uma gônada masculina de uma feminina, mas no caso dos machos genéticos já existe uma diferenciação da gônada a nível molecular. Nesta fase já se encontram presentes as estruturas das quais se desenvolvem os dutos mesonéfricos ou de Wolff precursores do aparelho genital masculino e os dutos paramesonéfricos ou de Müller que darão origem ao aparelho reprodutor feminino. Há uma série de fatores envolvidos no desenvolvimento precoce da gônada, entre os quais o fator esteroidogênico I (SFI: Steroidogenic fator l), que é um membro da subfamília de receptores nucleares, receptores órfãos. Este fator de transcrição tem um local de ligação ao DNA composto por dois dedos-de-Zinc. O SFI foi identificado como um ativador de genes envolvidos na biossíntese de esteroides em diferentes células. O SFI está presente durante o desenvolvimento embrionário em regiões associadas com funções endócrinas como gônadas, adrenais, pituitárias e hipotálamos. Os animais homozigotos para o gene SFI defeituoso, necessitam de gônadas e adrenais e têm a função gonadotrófica alterada. Os ratos sem SFI carecem de gonadotrofos e têm um desenvolvimento anormal do núcleo ventro-medial do hipotálamo; em particular as gônadas deixam de se desenvolver entre os dias 11 a 15 e degeneram-se por apoptose. No entanto, a crista genital forma-se e é colonizada pelas células germinativas, o que indica que estas continuam a receber o sinal adequado para a sua migração. Portanto, o SFI não está envolvido no desenvolvimento precoce da gônada e do sistema urogenital, mas parece estar envolvido na manutenção do crescimento das células somáticas presentes na gônada indiferenciada. O gene associado ao tumor de Wilms (WTI: Wilm's tumor Associated) está envolvido no desenvolvimento da gônada e do rim. Durante o desenvolvimento embrionário, WTI se expressa em todo o mesoderma intermediário e posteriormente na gônada indiferenciada, bem como no rim em formação. WTI regula o sinal indutivo do mesênquima para o epitélio celômico dos mesonefros. Se este for o caso, então WTI é responsável pelo crescimento da crista genital ao dirigir a entrada do epitélio celômico. Dado que estas células darão origem às células de Sertoli, a carência de WTI pode causar o desenvolvimento de embriões XY como fêmeas simplesmente porque não se formam as células de Sertoli. Em geral, todos os genes importantes na diferenciação do mesoderma intermediário e do sistema urogenital intervêm no desenvolvimento da gônada precoce. 1.4 DIFERENCIAÇÃO GONODAL O desenvolvimento das gônadas e ductos genitais descritos até o momento, é o mesmo para ambos os sexos. Igualmente, os genes descritos, que estão envolvidos no desenvolvimento das gônadas, ductos genitais e migração das células germinativas, afetam igualmente os embriões com genótipo XX ou XY. A gônada primitiva consiste anatomicamente de uma medula (interna) e uma crosta (externa), e de acordo com o local onde ocorre a colonização das células germinativas, diferenciara em testículo ou um ovário, respectivamente. Nos mamíferos, a primeira manifestação estrutural de diferenciação sexual é detectada na gônada dos machos, onde as células germinativas estão localizadas na medula. A diferenciação do testículo inicia-se quando os cordões sexuais se separam do epitélio celômico como consequência dos arranjos produzidos por uma invasão do mesênquima e vasos sanguíneos que provoca a compactação dos cordões, agora denominados cordões testiculares. As células que rodeiam os cordões se achatam e formam as células mioides, que são responsáveis pela formação das membranas basais. As células do epitélio interno, ou seja, as células de Sertoli, têm duas funções principais: o suporte das CGP e a síntese da hormona antimulleriana, responsável pela regressão dos ductos de Müller e secretada durante o período de diferenciação sexual. As células do estroma que rodeiam os cordões testiculares diferenciam-se para formar vários tipos de células: células mioides, fibroblastos, endotélio e células de Leydig, que são as mais importantes pela sua atividade endócrina. Posteriormente, os cordões testiculares dão origem aos túbulos seminíferos, que contêm o epitélio que produzirá os espermatozoides ao chegar à puberdade. Na fêmea, durante os estágios iniciais de diferenciação gonodal, não se observam mudanças em relação à gônada indiferenciada, só pode-se observar um certo crescimento devido à proliferação de células somáticas e germinativas. As células germinativas iniciam um período de proliferação, que termina com o início da meiose. Iniciada a meiose, dá-se o processo de foliculogênese; neste momento os cordões epiteliais se fragmentam, de tal maneira que cada ovócito fica rodeado de células epiteliais cobertas por uma folha basal fina (figura 1). Para que a gônada primitiva se desenvolva em testículo é indispensável a presença do cromossoma Y, independentemente do número de cromossomas X que contenha o genoma de um indivíduo. O gene determinante do testículo encontra-se localizado no cromossoma Y, denominado sry em ratos e SRY em humanos. O gene sry se expressa durante o desenvolvimento embrionário na crista genital de embriões de camundongos. A expressão é detectável no dia 10,5, pouco depois do aparecimento das cristas genitais, atinge o seu máximo durante o dia 11,5 e mantém-se até pouco depois de ocorrerem os primeiros sinais morfológicos de diferenciação testicular no dia 12,5. Este padrão de expressão é compatível com a teoria de que sry atua induzindo a ativação dos genes (figura 2) que conduzem ao desenvolvimento testicular, sem que exista a necessidade da expressão contínua de sry para manter a diferenciação do testículo após o dia 12,5. Como mencionado anteriormente, a gônada primitiva é composta por vários tipos de células. No entanto, as células germinativas primordiais não são o local de expressão do sry, já que os embriões que necessitam de células germinativas mantêm a expressão de sry e desenvolvem o sexo gonodal normalmente. As células somáticas na gônada em desenvolvimento incluem também as células de suporte. Sabe-se que é nestas células que o sry é expresso para que se diferenciem em células de Sertoli, e a expressão transitória de sry indica que deve ativar a outros genes para a manutenção das células de Sertoli. Uma vez diferenciadas as células de Sertoli, elas se encarregarão da diferenciação do resto das células na gônada. -/- Figura 1: Representação da diferenciação dos órgãos genitais internos. Adaptado de BRONSON, 1989. Figura 2: Cascada de genes envolvidos na diferenciação sexual, adaptado de KOOPMAN, 1999. O fator sry é necessário para a diferenciação do testículo. Embora não se conheçam os genes que provavelmente regulam esse gene, estudos realizados em camundongos demonstram que este gene parece coordenar-se com certos genes autossômicos. Entre estes genes autossômicos, o sox9, que é produzido pelas células de Sertoli uma vez que são estimuladas por sry, de modo que sox9 é um dos genes relacionados estruturalmente com sry. O Sox9 funciona como um fator de transcrição, mas não se sabe se a proteína tem qualquer outra função estrutural; este gene exprime-se abundantemente nos condrócitos e está relacionado com defeitos do aparelho ósseo chamados displasia campomélica. Curiosamente, os pacientes XY com esta condição sofrem frequentemente de reversão do sexo. O Sox9 é um dos poucos genes, além do SRY, do qual as mutações demonstraram interferir com a determinação sexual masculina. No entanto, apenas 75% dos pacientes com anomalias esqueléticas de tipo displasia campomélica têm reversão sexual e não foram encontrados casos de reversão sexual devido a um defeito de Sox9 que não seja acompanhado de defeitos esqueléticos. Isso indica que o Sox9 é apenas um membro da rede de genes que são ativados para determinar a diferenciação sexual, enquanto a rota que rege a condrogênese é mais sensível a perturbações deste. O momento em que se detecta a expressão do gene Sox9 (11dpc em ratos) coincide com a máxima expressão de sry, o que poderia indicar a possibilidade de que sry regule positivamente a Sox9. De fato, na região do promotor de Sox9 há um local de união ao que potencialmente se pode unir o sry. A expressão de Sox9 durante a diferenciação sexual sugere um papel abaixo de sry na diferenciação das células de Sertoli. O cromossoma X também é importante na diferenciação gonodal. O gene DAX-I foi isolado do lócus DSS (Dosage sensitive sex reversal) do cromossoma X. DAX-I é parte da cascata de determinação sexual, mas não é necessário para a formação do testículo. DAX-I é um membro dos receptores nucleares conhecidos como receptores órfãos. Este gene demonstrou ser um poderoso repressor da transcrição de SFI e de vários genes. Os padrões de expressão de DAX-I são complementares daqueles de SFI, ambos expressos nas cristas genitais. Em resumo, dada a evidência exposta, desenvolveu-se a hipótese de que DAX-I é um antagonista de sry; esse antagonismo é dependente dos níveis relativos de DAX-I e sry e de um limiar que varia de espécie para espécie. A DAX-I foi classificada como o gene antitestículo. Na fêmea (cariótipo XX) é importante que ocorra a inativação de um dos cromossomas sexuais X para que se mantenha o equilíbrio genético ao igualar o conteúdo de DNA dos cromossomas. Esse cromossoma inativado constitui o chamado corpúsculo de Barr. No entanto, para que a meiose se realize, é necessário dos dois cromossomas X ativos nos ovócitos para assegurar a diferenciação ovárica e a fertilidade. 1.5 DIFERENCIAÇÃO DOS DUCTOS SEXUAIS O embrião possui, além das gônadas indiferenciadas, dois sistemas de ductos: os de potencialidade masculina denominam-se ductos de Wolff ou mesonéfricos, e os de potencialidade feminina se chamam ductos de Müller ou paramesonéfricos (figura 1). Se a diferenciação gonodal levou à formação de um testículo, a partir do ducto mesonéfrico ou de Wolff se desenvolverão os ductos eferentes, o epidídimo, os ductos deferentes e as vesículas seminais. As hormonas importantes no desenvolvimento do aparelho genital masculino são a testosterona, produzida pelas células de Leydig, e sua forma 5α reduzida, a 5α di-hidrotestosterona. Acredita-se que a testosterona é responsável pela virilização dos ductos de Wolff, e a di-hidrotestosterona dos órgãos genitais externos. No macho, os canais de Müller atrofiam-se devido à ação de uma hormona fetal de origem testicular denominada hormona inibidora das estruturas de Müller (HIM) ou hormona antimulleriana. Este processo começa assim que os cordões espermáticos se formam e se diferenciam as células de Sertoli. A existência de HIM foi proposta baseada em estudos realizados em bezerras freemartin, devido à existência de uma hormona responsável pela atresia dos ductos de Müller que na fêmea dá origem ao útero e aos ovidutos. Essa hormona provoca a involução do aparelho genital do bovino nas gestações gemelares nas quais os produtos de diferente sexo têm comunicação sanguínea por ter ocorrido a anastomose dos vasos de ambas as placentas (figura 3). A HIM é uma glicoproteína pertencente à subfamília de TGFβ, é expressa pelas células que darão origem às células de Sertoli e é um dos primeiros marcadores de diferenciação nestas células. A HIM é secretada na vida adulta pelas células de Sertoli no testículo e por células da granulosa no ovário. No rato a HIM é expressa-se no 12° dia em um teste padrão que segue muito de perto o aumento na expressão de sry. No macho, esta secreção de HIM continua durante a vida fetal e adulta, contudo os níveis de HIM declinam na puberdade devido a um aumento na secreção de testosterona. Vários fatores intervêm na regulação do gene de HIM, incluindo os acima descritos SFI e Sox9. O gene HIM contém segmentos de DNA que são conservados em várias espécies de vertebrados. Existe um nexo de ligação para SFI, que ativa a transcrição de HIM. A mutação no local de ligação de SFI resulta em reversão do sexo em indivíduos XY incluindo genitais femininos normais, presença de um útero formado enfatizando a importância de SFI na determinação sexual e na expressão de HIM. Embora SFI seja um bom candidato como regulador de HIM, é expresso em outras células, como as de Leydig e adrenais, que não expressam HIM. Em contrapartida, Sox9 é expresso unicamente nas células de Sertoli que são as produtoras de HIM. O gene HIM também tem um nexo de ligação para Sox9. Além disso, Sox9 pode atuar sinergicamente com SFI para promover a secreção de HIM. Ao contrário destes dois fatores de transcrição, DAX-I antagoniza a ação de Sox9 e provavelmente SFI sobre o promotor de HIM. Assim, para que as células de Sertoli secretem HIM, a transcrição de DAX-I deve diminuir. Figura 3: Representação da diferenciação dos órgãos genitais externos. Adaptado de BRONSON, 1989. Os ductos de Wolff tornam-se o sistema de ejaculação do macho. A porção mais próxima dos testículos dá origem ao epidídimo, a parte central ao ducto deferente e a porção mais distal às vesículas seminais. A próstata e a parte membranosa da uretra do macho desenvolvem-se a partir da porção pélvica do seio urogenital. A virilização e diferenciação dos ductos de Wolff dependem da produção de testosterona pelo testículo. Quanto aos órgãos genitais externos do macho, o tubérculo genital é ampliado e as dobras uretrais se fundem para formar a uretra peniana. A fusão das dobras uretrais aproxima os tubérculos genitais para formar o escroto (figura 4). Figura 4: Diferenciação do aparelho genital da fêmea e do macho. Adaptado de KOOPMAN, 1989. A diferenciação dos órgãos genitais da fêmea ocorre de forma passiva, já que a ausência de testículos e por isso da hormona inibidora dos ductos de Müller (HIM), assim como dos andrógenos virilizantes, favorece o desenvolvimento dos ductos de Müller, enquanto os de Wolff sofrem atrofia. A porção cefálica dos ductos de Müller dá origem aos ovidutos, que na sua terminação caudal se fundem com o útero. O contato dos ductos de Müller com o seio urogenital induz uma intensa proliferação celular que resulta na formação da área uterovaginal localizado entre o seio urogenital e os ductos de Müller. As células do prato uterovaginal proliferam e aumentam a distância entre as duas estruturas criando o espaço que formará a vagina quando o prato é canalizado e forma um lúmen. Em contraste com o que ocorre no macho, na fêmea a maior parte do seio urogenital se mantém exposta na superfície da abertura onde desembocam a vagina e a uretra. O tubérculo urogenital da fêmea tem um crescimento limitado e forma o clitóris. A sequência de passos da diferenciação sexual do aparelho genital é resumida na tabela 1. Tabela 1: Destino em desenvolvimento dos rudimentos sexuais dos fetos macho e fêmea dos mamíferos -/- Rudimento sexual Macho Fêmea Gônada Testículo Ovário Ductos de Müller (Paramesonéfricos) Vestígios Útero, parte da vagina, ovidutos Ductos de Wolff (Mesonéfricos) Ductos eferentes deferentes, epidídimo, vesículas seminais Vestígios Seio urogenital Uretra, próstata, glândulas bulbouretrais Parte da vagina, uretra, vestíbulo, glândulas vestibulares Tubérculo genital Pênis Clitóris Pregas vestibulares Escroto Lábios vulvares Fonte: HAFEZ, 2004. 1.6 DIFERENCIAÇÃO SEXUAL DO HIPOTÁLAMO Os processos de diferenciação sexual não se limitam apenas às células somáticas do organismo do feto, mas incluem também os centros nervosos superiores do cérebro. Assim, da mesma maneira que a gônada e os ductos sexuais se desenvolvem para o tipo feminino ou masculino, propôs-se que o cérebro pode ser "masculinizado" ou permanecer "Feminizado". A diferenciação do hipotálamo vai depender do ambiente esteroidal do neonato e ocorre na fase perinatal. Estes eventos serão de grande transcendência na vida reprodutiva do indivíduo. Tanto a fêmea como o macho nascem com a capacidade de secreção de gonadotropinas de acordo com um padrão cíclico; contudo, no macho, a exposição do hipotálamo à ação dos andrógenos testiculares durante os primeiros dias da vida extrauterina provoca a masculinização, com o qual o hipotálamo do macho é programado para que a secreção de gonadotropinas se realize a um ritmo relativamente constante por parte da hipófise (secreção tônica). Na fêmea, tanto a secreção tônica como a cíclica se conservam. No entanto, observou-se que a injeção de testosterona ou o transplante de testículo na rata fêmea durante os primeiros dias de vida, suprime a sua futura atividade estral (secreção cíclica). Por outro lado, se os ovários forem transplantados para o rato macho normal castrado na idade adulta, o animal não desenvolve qualquer atividade cíclica, mas se os machos transplantados forem castrados ao nascer, o ovário é capaz de efetuar mudanças cíclicas e ovulações. Isto foi demonstrado em roedores, mas não em animais domésticos ou na espécie humana. Portanto, o padrão de secreção de gonadotropinas, seja cíclico ou tônico, não depende da hipófise, mas do hipotálamo e sua correta diferenciação. 1.7 CONCLUSÕES A maioria dos conhecimentos no campo da biologia do desenvolvimento e, muito especificamente, dos processos de diferenciação sexual têm sido originados de estudos relacionados com desordens congênitas, que na sua maioria devem-se a defeitos de genes específicos. A análise detalhada destas desordens permitiu entender alguns mecanismos endócrinos, moleculares e genéticos envolvidos na diferenciação sexual. A identificação do gene sry como determinante do testículo foi uma contribuição crucial e abriu as portas à compreensão dos mecanismos moleculares e celulares relacionados com o desenvolvimento do testículo. Se este gene não estiver presente, é criado um programa genético alternativo para levar a cabo a diferenciação gonodal para o ovário. Finalmente, devemos ter presente que é necessária uma correlação entre mudanças morfológicas e expressão de genes durante o desenvolvimento para entender os mecanismos relacionados com a diferenciação. -/- Apoio -/- Realização -/- REFERÊNCIAS BIBLIOGRÁFICAS ANDERSON, Robert et al. The onset of germ cell migration in the mouse embryo. Mechanisms of development, v. 91, n. 1-2, p. 61-68, 2000. AUSTIN, Colin Russell; SHORT, R. V. Reproduction in Mammals: Volume 1, Germ Cells and Fertilization. Londres: Cambridge University Press, 1972. BRONSON, Franklin H. Mammalian reproductive biology. Chicago: University of Chicago Press, 1989. BUEHR, Mia. The primordial germ cells of mammals: some current perspectives. Experimental cell research, v. 232, n. 2, p. 194-207, 1997. BYSKOV, Anne G. Differentiation of mammalian embryonic gonad. Physiological reviews, v. 66, n. 1, p. 71-117, 1986. CAPEL, Blanche et al. Migration of mesonephric cells into the mammalian gonad depends on Sry. Mechanisms of development, v. 84, n. 1-2, p. 127-131, 1999. CAPEL, Blanche. The battle of the sexes. Mechanisms of development, v. 92, n. 1, p. 89-103, 2000. DERIVAUX, Jules; BARNABÉ, Renato Campanarut. Reprodução dos animais domésticos. Zaragoza: Acribia, 1980. DOMENICE, Sorahia et al. Aspectos moleculares da determinação e diferenciação sexual. Arquivos Brasileiros de Endocrinologia & Metabologia, v. 46, n. 4, p. 433-443, 2002. DONAHOE, Patricia K. et al. Mullerian inhibiting substance activity in bovine fetal, newborn and prepubertal testes. Biology of reproduction, v. 16, n. 2, p. 238-243, 1977. HAFEZ, Elsayed Saad Eldin; HAFEZ, B. Reprodução animal. São Paulo: Manole, 2004. HANLEY, Neil A. et al. Steroidogenic factor 1 (SF-1) is essential for ovarian development and function. Molecular and cellular endocrinology, v. 163, n. 1-2, p. 27-32, 2000. HIORT, Olaf; PAUL-MARTIN, H. The molecular basis of male sexual differentiation. European journal of endocrinology, v. 142, n. 2, p. 101-110, 2000. HOLY, Lubos; MARTÍNEZ JÚSTIZ, G. Colab. Biología de la reproducción bovina. Havana: Revolucionária, 1975. JOSSO, Nathalie et al. The role of anti-Müllerian hormone in gonadal development. Molecular and cellular endocrinology, v. 145, n. 1-2, p. 3-7, 1998. JOST, Alfred et al. Studies on sex differentiation in mammals. In: Proceedings of the 1972 Laurentian Hormone Conference. Londres: Academic Press, 1973. p. 1-41. KNOBIL, Ernst. Knobil and Neill's physiology of reproduction. EUA: Gulf Professional Publishing, 2006. KOFMAN ALFARO, S.; MERCHANT LARIOS, H.; PEREZ PALACIOS, G. Diferenciacion sexual. I. Bases biologicas del dimorfismo sexual. Rev. invest. clín, p. 349-59, 1982. KOOPMAN, Peter. Sry and Sox9: mammalian testis-determining genes. Cellular and Molecular Life Sciences CMLS, v. 55, n. 6-7, p. 839-856, 1999. MCDONALD, L. E. Veterinary endocrinology. Lea & Febiger, Philadelphia, Pa, 1969. MEIZEL, S.; JOHNSON, M. H. Development in mammals. MH Johnson, Ed, v. 3, p. 1-64, 1978. MELLO, Maricilda Palandi de; ASSUMPÇÃO, Juliana de G.; HACKEL, Christine. Genes envolvidos na determinação e diferenciação do sexo. Arquivos Brasileiros de Endocrinologia & Metabologia, v. 49, n. 1, p. 14-25, 2005. -/- REFERÊNCIAS BIBLIOGRÁFICAS MERCHANT-LARIOS, H. Ovarian differentiation. The Vertebrate Ovary, p. 47-81, 1978. MIES FILHO, Antonio. Reprodução dos animais. Porto Alegre: Sulina, 1987. NEF, Serge; PARADA, Luis F. Hormones in male sexual development. Genes & Development, v. 14, n. 24, p. 3075-3086, 2000. PARKER, Keith L.; SCHEDL, Andreas; SCHIMMER, Bernard P. Gene interactions in gonadal development. Annual review of physiology, v. 61, n. 1, p. 417-433, 1999. SWAIN, Amanda; LOVELL-BADGE, Robin. Mammalian sex determination: a molecular drama. Genes & development, v. 13, n. 7, p. 755-767, 1999. WILHELM, Dagmar; PALMER, Stephen; KOOPMAN, Peter. Sex determination and gonadal development in mammals. Physiological reviews, v. 87, n. 1, p. 1-28, 2007. WILSON, Jean D.; GRIFFIN, James E.; GEORGE, Fredrick W. Sexual differentiation: early hormone synthesis and action. Biology of reproduction, v. 22, n. 1, p. 9-17, 1980. -/- Emanuel Isaque Cordeiro da Silva Belo Jardim, 07 de Maio de 2020. (shrink)

This introductory chapter provides an overview of the recent debate about responsibility and distributive justice. It traces the recent philosophical focus on distributive justice to John Rawls and examines two arguments in his work which might be taken to contain the seeds of the focus on responsibility in later theories of distributive justice. It examines Ronald Dworkin's ‘equality of resources’, the ‘luck egalitarianism’ of Richard Arneson and G. A. Cohen, as well as the criticisms of their work put forward (...) by Elizabeth Anderson, Marc Fleurbaey, Susan Hurley, and Jonathan Wolff. Key concepts such as responsibility (individual and collective), luck (thin and thick; brute and option), control, desert, and equality of opportunity are delineated, and the implementation of responsibility-sensitive accounts of justice is considered. The chapters of this book are positioned in relation to the wider literature on responsibility and distributive justice, and a brief outline of the chapters is provided. (shrink)

What does it take for lawyers and others to think or talk about the same legal topic—e.g., defamation, culpability? We argue that people are able to think or talk about the same topic not when they possess a matching substantive understanding of the topic, as traditional metasemantics says, but instead when their thoughts or utterances are related to each other in certain ways. And what determines the content of thoughts and utterances is what would best serve the core purposes of (...) the representational practice within which the thought or utterance is located. In thus favoring a “relational model” in metasemantics, we share Ronald Dworkin's goal of explaining fundamental legal disagreements, and also his reliance on constructive interpretation. But what we delineate is a far more general and explanatorily resourceful metasemantics than what Dworkin articulated, which also bypasses some controversial implications for the nature of law that Dworkin alleged. (shrink)

One of the best-known members of the United Nations Commission which drafted the 1948 "Universal Declaration of Human Rights," Jacques Maritain, famously held that the "natural rights" or "human rights" possessed by every human being are grounded and justified by reference to the natural law.' In many quarters today, the notion of the natural law, and arguments for a set of natural rights grounded in the natural law, have come under fierce attack. One common line of attack is illustrated by (...) the arguments of some utilitarians, for whom "natural law thinking" is mistaken insofar as it implies that there is an absolute moral prohibition against violating any human being's "natural rights." Even if there is such a thing as "natural rights," these utilitarians argue, such rights - including even the natural "right to life" - are necessarily relational, and thus have meaning only within the context of a larger social whole. As a result, the argument goes, the supposed "natural rights" possessed by individual human beings are never inviolable or unconditional, but instead always negotiable and subject to being "traded away" for the sake of greater social utility. Consider just one alleged counter-example to the notion that there are inviolable or unconditional "natural rights": it is well-known that approximately 36,000 people in the United States die every year as a result of influenza infections or influenza-related complications.' There is little doubt that hundreds, and probably even thousands, of human lives would be saved every year if local governments were to pass laws requiring flu vaccinations for all members of at-risk populations (e.g., the very young and the very elderly). It would seem that there would be broad support for mandated flu vaccinations- no matter what the expense - if human lives would be saved and if the natural "right to life" is inviolable or unconditional.' And yet no such life-saving laws exist, apparently because citizens and legislators believe that the social costs and inconveniences would be too great. According to the utilitarian position, this demonstrates - contrary to what Ronald Dworkin and others say about rights' - that rights do not trump utility, but in fact are quite regularly and reasonably trumped by utility. In light of such contemporary understandings and policies, can natural law thinking about natural rights be made credible? In what follows, I shall argue that utilitarian thinkers are correct to hold that rights are intrinsically relational; but they are wrong to conclude that the relational character of rights entails that "natural rights" are not inviolable or not unconditional. (shrink)

Regarding the relation of Plato’s early and middle period dialogues, scholars have been divided to two opposing groups: unitarists and developmentalists. While developmentalists try to prove that there are some noticeable and even fundamental differences between Plato’s early and middle period dialogues, the unitarists assert that there is no essential difference in there. The main goal of this article is to suggest that some of Plato’s ontological as well as epistemological principles change, both radically and fundamentally, between the early and (...) middle period dialogues. Though this is a kind of strengthening the developmentalistic approach corresponding the relation of the early and middle period dialogues, based on the fact that what is to be proved here is a essential development in Plato’ ontology and his epistemology, by expanding the grounds of development to the ontological and epistemological principles, it hints to a more profound development. The fact that the bipolar and split knowledge and being of the early period dialogues give way to the tripartite and bound knowledge and benig of the middle period dialogues indicates the development of the notions of being and knowledge in Plato’s philosophy before the dialogues of the middle period. -/- Keywords Plato; early dialogues; middle dialogues; being; knowledge; development -/- Introduction The differences between two groups of the early and middle period dialogues have always been a matter of dispute. Whereas the developmentalists like Vlastos, Silverman (2002), Teloh (1981), Dancy (2004) and Rickless (2007) think that from the early to the middle dialogues Plato’s philosophy changes, at least in some essential points, the unitarists like Kahn, Cherniss and Shorey believe that there happens no development and the differences must be taken as natural, ignorable and even pedagogic. In his well-known article, Socrates contra Socrates in PLATO, Vlastos lists ten theses of difference between two groups of dialogues. The first group which includes Plato’s early dialogues he divides to 'elenctic' (Apology, Charmides, Crito, Euthyphro, Gorgias, Hippias Minor, Ion, Laches, Protagoras and Republic I) and 'transitional' (Euthydemus, Hippias Major, Lysis, Menexenus and Meno) dialogues. These transitional come after all the elenctic dialogues and before all the dialogues of the second group which compose Plato’s middle period dialogues, including (with Vlastos' chronological order) Cratylus, Phaedo, Symposium, Republic II-X, Phaedrus, Parmenides and Theaetetus (1991, 46-49). Vlastos asserts strictly that his list of differences are 'so diverse in content and method that they contrast as sharply with one another as with any third philosophy you care to mention, beginning with Aristotole’s' (ibid, 46). Vlastos’ list of differences between two Socrateses is considered a view breaking sharply between the early and the middle dialogues. Besides all ten differences between the two Socrateses in Vlastos’ list that can be supportive for our doctrine here, we intend to focus on some ontological as well as epistemological distinctions that have not completely been discussed hitherto. Contrary to the developmentalist theory of Vlastos, unitarian theory of Charles Kahn wishes to eliminate any substantial difference between the early and the middle dialogues. He distinguishes seven 'pre-middle' or 'threshold' dialogues including Laches, Charmides, Euthyphro, Protagoras, Meno, Lysis and Euthydemus from the other Socratic dialogues which he calls 'earliest group' (1996, 41). The threshold dialogues, Kahn thinks, 'embarke upon a sustained project' that is to reach to its climax in the middle period dialogues, namely Phaedo, Symposium and Republic. Believing in that there is no 'fundamental shift'between the early and middle dialogues (ibid, 40), Kahn thinks the Socratic dialogues are just the 'first stage' with a 'deliberate silence' towards the theories of later periods (ibid, 339). One of the reasons of the surprising fact that Plato gives no hint of the metaphysics and epistemology of the Forms in the early dialogues, he thinks, is the pedagogical advantages of aporia. He thinks that Plato 'obscurely', and mostly because of education, hinted to some doctrines and conceptions in his early dialogues and with the aim of clarifying them only in the later ones (ibid, 66). The seven threshold dialogues, Kahn asserts, 'had been designed from the first' to prepare the pupils and readers for the views expounded in the middle period dialogues (ibid, 59-60). To show that the differences of the two Socrateses of the early and middle period dialogue are in their onto-epistemological grounds and thence cannot be explained by a unitaristic view, we try to draw the ontological and epistemological principles of the early dialogues in the first part below in order to show, in the second part, that those principles have been developed in the middle period dialogues. -/- A. The Onto-Epistemologic Principles of the Early Dialogues Socratic dialogues are paradoxical about knowledge because while being knowledge-oriented always searching for knowledge, they deny it and even never discuss it directly. Three elements of Socrates’ way of searching Knowledge throughout the early dialogues, i.e. Socratic 'what is X?' question, his disavowal of knowledge and his elenctic method combined together produce something like a circle which works, more or less, in the same way in these dialogues. Though this circle is an embaressing inquiry always resulting in ignorance instead of knowledge, its motivation is surprisingly Socrates’ passionate enthusiasm for knowledge, an intensive love of wisdom. The starting point of this circle is Socrates’ confession of having no knowledge which might be explicitly asserted or presupposed, maybe because it was one of the famous characteristics of Socrates; a confession always paradoxically accompanied with his intense longing for knowledge (e.g., Gorgias 505e4-5). Every time Socrates encounters with someone who thinks he knows something (οἴεταί τι εἰδέναι) (Apology 21d5) and tries to examine him. This examination seems to be the simplest one asking just what it is that he knows. Socrates’ elenchus, therefore, is always connected with 'what is X?' (τίς ποτέ ἐστιν) question, a question that most of the early dialogues of Plato are concerned with; 'what is courage?' in the Laches, 'what is piety?' in Euthydemus, 'what is temperance?' in Charmides and 'what is beauty?' in Hippias Major. This question we call here 'Socratic question' and probably is the very question the historical Socrates used to employ, is tightly interrelated with both his disavowal and his elenchus. He disclaims knowledge because he cannot find the answer to the question himself and he rejects others’ since they cannot offer the correct answer too. Every interlocutor can claim he knows X, if and only if he can answer the Socratic question. Otherwise, he is more of an ignorant than of a knower of τί ποτέ ἐστι X. Knowing the answer to this question is, thus, knowledge’s criterion for Socrates. Having found out that he cannot answer what it is which he would claim to know, the interlocutor comes to the point Socrates was there at the beginning. The least advantage of this circle is that he becomes as wise as Socrates does about the subject, becoming aware that he does not know it. At the end of the circle they are both still at the beginning, not knowing what X is. So let us first take a glance at these three elements. Socratic disavowal of knowledge is strictly asserted in some passages. At Apology 21b4-5, Socrates says: -/- I do not know of myself being wise at all (οὔτε μέγα οὔτε σμικρὸν σύνοιδα ἐμαυτῷ σοφὸς ὤν) -/- Moreover, at 21d4-6: -/- None of us knows anything worthwhile (καλὸν κἀγαθὸν εἰδέναι) …. I do not know (οἶδα) neither do I think I know. -/- In Charmides Socrates speaks about a fear about his probable mistake of thinking that he knows (εἰδέναι) something when he does not (166d1-2). The somehow generalization of this disavowal can be seen in Gorgias. After calling his disavowal 'an account that is always the same' (509a4-5), Socrates continues (a5-7): -/- I say that I do not know (οἶδα) how these things are, but no one I have ever met, like now, who can say anything else without being absurd. -/- At the end of Hippias Major (304d7-8), Socrates affirms his disavowal of knowledge of 'what is X?' this time about the fine: -/- I do not know (οἶδα) what that is itself (αὐτὸ τοῦτο ὅτι ποτέ ἐστιν). Some other passages, however, made a number of scholars dubious about Socrates’ disavowal. Vlastos mentions Apology 29b6-7 as an evidence : 'that to do wrong and to disobey one’s master, both god and men, I know (οἶδα) to be evil and shameful'. He thinks that if we give this single text 'its full weight' it can suffice to show that Socrates does claim knowledge of a moral truth (1985, 7). Vlastos’ claim is not admittable since it would be too strange, I think, for a man like Socrates to violate his disavowal claim just after emphasizing it. We can see his claim just before the already mentioned passage: -/- And surely it is the most blameworthy ignorance to believe that one knows what one does not know. It is perhaps on this point and in this respect, gentlemen, that I differ from the majority of men and if I were to claim that I am wiser than anyone in anything it world be in this, that, as I have no adequate knowledge (οὐκ εἰδὼς ἱκανῶς) of things in the underworld, so I do not think I have (οὐκ εἰδέναι) (Apology 29b1-6) Vlastos tries to solve what he calls the 'paradox' of Socrates’ disavowal of knowledge distinguishing the 'certain' knowledge from 'elenctic' knowledge (1985, 11) and thinking that when Socrates avows knowledge, we must perceive it as an elenctic knowledge, a knowledge its content 'must be propositions he thinks elenctically justifiable' (ibid, 18). Irwin’s solution is the distinction of knowledge and belief. He approves that Socrates does not 'explicitly' make such a distinction, but still thinks that Socrates’ 'test for knowledge would make it reasonable for him to recognize true belief without knowledge, and his own claims are easily understood if they are claims to true belief alone' (1977, 40). While I agree with Vlastos up to a point, I strongly disagree with Irwin about the early dialogues. As I will try to show below, we are not permitted to consider any kind of distinction within knowledge in Socratic dialogues because only one category of knowledge is alluded to there and the distinction of knowledge and belief thoroughly belongs to the second Sorcates. Although no kind of distinction can be admittable here, I think Vlastos’ distinction can be accepted only if we regard it as a distinction between knowledge, which is unique and without any, even incomparable, rival, and a semi-idiomatic and ordinary one that is a necessary requirement for any argument, and thus, unavoidable even for someone who does not claim any kind of knowledge. An apparent evidence of this is Gorgias 505e6-506a4: -/- I go through the discussion as I think it is (ὡς ἄν μοι δοκῇ ἔχειν), if any of you do not agree with admissions I am making to myself, you must object and refute me. For I do not say what I say as I know (οὐδὲ γάρ τοι ἔγωγε εἰδὼς λέγω ἃ λέγω) but as searching jointly with you (ζητῶ κοινῇ μεθ᾽ ὑμῶν). -/- The minimal degree of knowledge everyone must have to take part in an argument, conduct it and use the phrase "I know" when it is necessary is what Socrates cannot deny. We can call it elenctic knowledge only if we agree that it is not the kind of knowledge that Socrates has always been searching, the one that can be accepted as the answer of Socratic 'what is X?' question. His disavowal of knowledge is applied only to the knowledge which can truly be the answer of Socratic question and pass the elenctic exam; a knowledge that, I believe, is never claimed by first Socrates. Socrates conducts his method of examining his interlocutors’ knowledge, our second element here, by almost the same method repeated in Socratic dialogues. That whether we are allowed to regard all the examinations of Socrates in the early dialogues as based on the same or not has been a matter of dispute. Vlastos himself (1994, 31) distinguished Euthydemas, Lysis, Menexenns and Hippias Major from the other Socratic dialogues because he thinks Socrates has lost his faith to elenchus in there. Irwin (1977, 38) distinguishes Apology and Crito where Socrates’ own convictions is present. Contrary to some scholars like Benson (2002, 107) who take elenchus in all the Socratic dialogues as a unique method, Michelle Carpenter and Ronald M. Polansky (2002, 89-100) argue pro the variety of methods of elenchus. Thomas C. Brickhouse and Nicholas D. Smith (2002, 145-160) even reject such a thing as Socratic elenchus which can gather all of the Socrates’ various arguments under such a heading. There can be no solution for the problem of elenchus, they think, is due to 'the simple reason that there is no such thing as 'the Socratic elenchos"'(p.147). Though we consider elenchus a somehow determined process and a part of Socratic circle in the early dialogues, all we assume is that whatever differences it might have in different dialogues, it has the same onto-epistemological principles and, thus, we are not going to take it necessarily as a unique method. This method sets out to prove that the interlocutors are as ignorant as Socrates himself is. That whether elenchus is constructive, capable of establishing doctrines as Vlastos (1994) or Brickhouse and Smith (1994, 20-21) believe or not is another issue to which this paper is not to claim anything. What is crucial for our discussion here is that elenchus does not reach to the very knowledge Socrates is looking for. This is strictly against Irwin who thinks that not only elenchus leads to positive results, 'it should even yield knowledge to match Socrates’ conditions'(1977, 68, cf. 48). He does not explain where and how they really yield to that kind of knowledge. He explains his elenctic method in his apology in the court (Apology 21-22), that how he used to examine wise men, politicians, poets and all those who had the highest reputation for their knowledge and every time found that they have no knowledge. If we accept, as I strongly do, that Socrates’ disavowal of his knowledge is not irony, it might seem more reasonable to agree that the process that has that disavowal as its first step cannot be irony as well. The key of the circle which can explain why Socrates disclaims knowledge and how he can reject others’ claim of having any kind of knowledge lies in the third element, Socratic question. In Hippias Major (287c1-2), Socrates asks: 'Is it not by Justice that just people are Just? (ἆρ᾽ οὐ δικαιοσύνῃ δίκαιοί εἰσιν οἱ δίκαιοι). He insists at 294b1 that they were searching for that by which (ᾧ) all beautiful things are beautiful (cf. b4-5, 8). At Euthyphro 6d10-11 it is said that the Socratic question is waiting for 'the form itself (αὐτὸ τὸ εἶδος) by which (ᾧ) all the pious actions are pious; and at 6d11-e1: -/- Through one form (που μιᾷ ἰδέᾳ) impious actions are impious and pious actions pious. -/- Since the X itself is that by which X is X, knowing 'X itself' is the only way of knowing X. It is probably because of this that Socrates makes the distinction between the ousia as a right answer to the question and effect as a wrong one: -/- I am afraid, Euthyphro, that when you were asked what piety is (τὸ ὅσιον ὅτι ποτ᾽ ἐστίν) you did not wish to make clear its nature itself (οὐσίαν … αὐτοῦ) to me, but you said some effect (πάθος) about it. (Euthp. 11a6-9) -/- 1. Knowledge of what X is Now it is time to look for the onto-epistemological principles of Socratic circle and its three elements. It cannot reasonably be expected from the first Socrates to present us explicitly and clearly formulated principles of his onto-epistemology when such explications cannot be found even in the second Socrates who has some obviously positive theoris. Since there must be some principles underlying this first systematic inqury of knowledge, we must seek to them and be satisfied with elicitation of the first Socratas’ principle. What will be drawn out as his principles cannot and must not, thus, be taken as very fix and dogmatic principles. Some very slightest principles and grounds suffice for our purposes here. The first principle that is the prima facie significance of the Socratic question and his implementation of all those elenctic arguments I call the principle of 'Knowledge of What X is' (KWX): -/- KWX To know X, it is required to know what X is. -/- Aristotle (Metaphysics 1078b23-25, 27-29, 987b4-8) takes Plato’s τί ἐστι question as seeking the definition of a thing that is the same as historical Socrates’ search but applying to a different field. That Plato’s 'what is X?' question was a search for definition became the prevailed understanding of this question up to now. I am going neither to discuss the answer of Socratic question nor to challenge taking it as definition. What I am to insist is that knowledge is attached firmly to the answer of the question: Knowledge of X is not anything but the knowledge of what X is. It entails, certainly, the priority of this knowledge to any other kind of knowledge about X but it also has something more fundamental about the relation of knowledge and Socratic question. Socrates’ exclusive focus on the answer of his question can authorize the consideration of such an essential role for KWX in his epistemolgoy. The total rejection of his interlocutors’ knowledge when they are unable to answer the question can be regarded as a strong evidence for it. Socrates’ elenctic method and his rejection of others’ knowledge in the early dialogues, which all end aporetically with no one accepted as knower and nothing as knowledge, prevent us from finding any positive evidence for this. We have to be content, therefore, of negative evidences which, I think, can be found wherever Socrates rejects his interlocutors’ knowledge when they are not able to give an acceptable answer to his 'what is X?' question. 2. Bipolar Epistemology Socrates’ rejection of his interlocutors’ knowledge has another epistemological principle as its basis. Let me call this principle Bipolar Epistemology' (BE): BE There is no third way besides knowledge and Ignorance. -/- BE says that about every object of knowledge there are only two subjective statuses: knowledge and Ignorance. Socrates’ disavowal, however, says nothing but that he is ignorant of knowledge of X because he does not know what X is. This means that BE is presupposed here. Socrates’ elenchus and his rejection of interlocutors’ having any kind of knowledge are the necessary results of the fact that he does not let any third way besides knowledge and ignorance. The first Socrates never let anyone partly know X or have a true opinion about it, as he would not let anyone know anything about X when he did not know what X is. -/- 3. Bipolar Ontology The principle of BE in first Socrates’ epistemology is parallel to another principle in his ontology. Plato’s bipolar distinction between being and not being is as strict and perfect as his distinction between knowledge and ignorance. This principle I shall call the principle of 'Bipolar Ontology' (BO): BO Being is and not being is not. BO is apparently the same with the well-known Parmenidean Principle of being and not being (cf. Diels-Kranz (DK) Fr. 2.2-5). Euthydemus’ statement against the possibility of false knowledge can be good evidence for this principle: -/- The things which are not surely do not exist (τὰ δὲ μὴ ὄντα … ἄλλο τι ἢ οὐκ ἔστιν). (Euthydemus 284b3-4) -/- He continues (b4-5): -/- There is nowhere for not being to be there (οὖν οὐδαμοῦ τά γε μὴ ὄντα ὄντα ἐστίν). -/- That BE does not let true opinion as a third option besides knowledge and ignorance seems to be related to BO’s rejecting a third option besides being and not being, which is itself the basis of the impossibility of false belief. Socrates’ elaborate discussion of the problem of false belief in Theatetus that leads to a more decisive discussion and finally to some solutions in Sophist can make our consideration of BO for the first group of dialogues authentive. -/- 4. &5. Split Knowledge and Split Being The fourth principle I shall call the principle of 'Split Knowledge' (SK): -/- SK Knowledge of X is separated from any other knowledge (of anything else) as if the whole knowledge is split to various parts. -/- This Principle is hinted and criticized as Socrates’ way of treating with knowledge in Hippias Major: -/- But Socrates, you do not contemplate the entireties of things, nor do people you have used to talk with (τὰ μὲν ὅλα τῶν πραγμάτων οὐ σκοπεῖς, οὐδ᾽ ἐκεῖνοι οἷς σὺ εἴωθας διαλέγεσθαι). (301b2-4) -/- Contrary to Rankin who regards the passage as 'antilogical, almost eristic in tone rather than presenting a serious philosophy of being' (1983, 54), I think it can be taken as serious. Hippias criticizes Sorcates that he does not contemplate (σκοπεῖς) the entireties of things (ὅλα τῶν πραγμάτων), a critique which Socrates is not its only subject but all those whom Socrates accustomed to talk with (ἐκεῖνοι οἷς σὺ εἴωθας διαλέγεσθαι). This last phrase, I think, extends this critic beyond this dialogue to other Socratic dialogues. Hippias’ use of the perfect tense of the verb ἔθω (to be accustomed) is a good evidence of this extension. We can get, thus, these ἐκεῖνοι as Socrates’ interlocutors in his other dialogues that hints that this criticism has the epistemological groundings of the previous dialogues as its subject. What ἐκεῖνοι οἷς σὺ εἴωθας διαλέγεσθαι points to is that Hippias does not have in mind Socrates’ way of treating things only in this dialogue, but he is also criticizing Socrates’ way throughout his dialogues. At 301b4-5, Socrates and his interlocutors’ way of beholding things is described as such: -/- You people knock (κρούετε) at the fine and each of the beings (ἕκαστον τῶν ὄντων) by taking each being cut up in pieces (κατατέμνοντες) in words (ἐν τοῖς λόγοις). This leads us to our next principle that is parallel to, and the ontological side of, SK, the principle of 'Split Being'(SB): -/- SB Everything (being) is separated from any other thing as if the whole being is split to many beings. -/- Socrates and his interlocutors and thus, as we saw, the Socratic dialogues are accused to regard everything as it is separated from all other things. This separation is en tois logois that, I think, can reasonably be taken as saying that Socratic dialogues (it refers of course to the dialogues before Hippias Major) cut up all things which have the same name/definition from all other things and try to understand them separately, without considering other things that are not in their logos. They, for example in Hippias Major, are cutting up to kalon and try to understand what it and all others inside this logos are by separating it from all other things. This is directed straightly against Socratic question and the way Socratic dialogues follow to find its answer, every time separating one logos. As Meyer (1995, 85) points out, every question 'presupposes that the X in question in a logos is something' and 'every answer to every question aims at unity' (84). The critique of Hippias Major is, therefore, at the same time a critique of SK and SB. It is also a critique of KWX because it is only based on KWX that Socratic dialogues could search for the answer of 'what is X' question supposing that knowing what X is is enough for the knowledge of X. SK and KWX are absolutely interdependent. What Socrates and all his previous interlocutors have neglected in Socratic dialogues, Hippias says, was 'continuous bodies of being' (διανεκῆ σώματα τῆς οὐσίας) (301b6). Either this theory actually belongs to the historical Hippias as it is being said or not, it is strictly criticizing SB. We have the same phrase with changing sūma to logos some lines later at 301e3-4: διανεκεῖ λόγῳ τῆς οὐσίας. Although this theory that can be observed as both an ontological and an epistemological theory is rejected by Socrates (301cff.), it is still against first Socrates’ onto-epistemological principles and might let us look at what is rejected as Socratic prineple. -/- 6. Knowledge is of Being The sixth principle that I think is presupposed by the first Socrates, is the 'Knowledge of Being' Principle (KB): -/- KB Knowledge is of Being. -/- This principle is obviously the source of the problem of false knowledge, a very important problem throughout Plato’s philosophy. We face this problem maybe for the first time in Euthydemus. In less than 20 Stephanus’ pages, 276-295, we are encountered with different interwoven problems about knowledge , all grounded in the problem of false opinion. Having challenged the obvious possibility of telling lies at 283e, at 284 Euthydemus discusses it saying that the man who speaks is speaking about 'one of those things that are (ἓν μὴν κἀκεῖνό γ᾽ ἐστὶν τῶν ὄντων)' (284a3) and thus speaks what is (λέγων τὸ ὄν) (a5). He must necessarily be saying truth when he is speaking what is because he who speaks what is (τὸ ὄν) and the things that are (τὰ ὄντα) speaks truth (τἀληθῆ λέγει) (a5-6). This is based on Parmenidean principle of the impossibility of being of not being which Euthydemus restates (284b3-4) and we mentioned discussing BO principle above. The things that are not are nowhere (οὐδαμοῦ) and there is no possibility for anyone to do (πράξειεν) anything with them because they must be made as being before anything else can be done, which is impossible (b5-7). The words, then, are of things that exist (εἰσὶν ἑκάστῳ τῶν ὄντων λόγοι) (285e9) and as they are (ὡς ἔστιν) (e10). The result is that no one can speak of things as they are not. It is this impossibility of false speach that is extended to thinking (δοξάζειν) at 286d1 and leads to the impossibility of false opinion (ψευδής … δόξα) (286d4). The general conclusion is asserted at 287a extending this impossibility to actions and making any kind of mistake. Not only knowledge is of being but speech, thought and action are of being simply because of the fact that nothing can be of not being. -/- B. First Socrates’ Principles in the Middle Period Dialogues Out of what were presupposed or criticized mostly in five dialogues, Euthyphro, Euthydemus, Hippias Major, Laches and Charmides, we tried to draw the first Socrates’ principles. Our inquiry here is directed to find out the fate of these principles in the three dialogues of the middle period, Meno, Phaedo and Republic. To do this, first we ought to check the situation of Socratic circle in these dialogues. The Socratic circle that was predominant in the early dialogues, does not look like a circle here anymore though they certainly have some features in common. Meno, Phaedo and Republic II-X are not committed to the principles of the circle and the whole circle in disrupted in them. The difference of the two Socrateses towards acquiring knowledge is obvious. The Socrates of Meno, Phaedo and Republic is evidently more self-confident that he can get to some truths during his arguments as he does. They are in their first appearance, as almost all other dialogues, committed to Socrates’ disavowal. All of them try to keep the shape of the Socratikoi Logoi genre, which is committed to the historical Socrates’ way of discussion; a dramatic personage who is to challenge his interlocutors, ask them and refuse the answers. Nevertheless, the fact is that what we have in common between two groups of dialogues is mostly a dramatic structure. Whereas the first group’s arguments are based on Socrates’ disavowal and lead to no positive results, the second group is decisively going to achieve some positive results. The aim of the first Socrates was to show others that they are ignorant of what they thought they knew. The new Socrates of Meno, on the opposite, makes so much efforts to show that the slave boy has within himself true opinions (ἀληθεῖς δόξαι) about the things that he does not know (οἶδε) (85c6-7). Despite his lack of knowledge, he has true opinions nevertheless. The way from these true opinions to knowledge, as Socrates states, is not so long. These true opinions are now like a dream but 'can become knowledge of the same things not less accurate than anyone’s' (οὐδενὸς ἧττον ἀκριβῶς ἐπιστήσεται περὶ τούτων) (c11-d1), if they be repeated by asking the same questions. The most outstanding text regarding Socrates’ disavowal is Meno 98b where he explicitly claims knowledge: -/- And indeed I also speak as (ὡς) one who does not know (εἰδὼς) but is guessing (εἰκάζων). However, [about the fact] that true opinion and knowledge are different, I do not altogether expect (δοκῶ) myself to be guessing (εἰκάζειν), but if I say about anything that I know (εἰδέναι) -which about few things I say- this is one of the things that I know (οἶδα). (98b1-5) This passage is very significant about Plato’s disavowal of knowledge. There can hardly be found, I think, anywhere else in Plato’s corpus where Socrates speaks about his knowledge of something as such. He says first that he speaks as someone who does not know. This ὡς οὐκ εἰδὼς λέγω comparing with what he used to say in the first group, οὐκ οἶδα, has this added ὡς. Socrates does not claim strongly anymore that he does not know anything but speaks only as someone who does not know. He needs this ὡς not only because he is going to accept that he does know some, though few, things immediately after this sentence, but also because he needs his previous disavowal to be loosened from Meno on. He does not merely say here that he knows something. It is then different from the examples mentioned before which could be taken as idiomatic or at least not emphatic. Socrates’ remarkable emphasis on distinguishing εἰδέναι from εἰκάζειν departs it from all other passages where he says only he knows something. Moreover, he claims definitely that he has knowledge about few (ὀλίγα) things. From the early to the middle dialogues, Socrates’ attitude to knowledge has totally renewed its face. He brings forth a new concept, true opinion, and he does not speak of knowledge as he used to before; the rough, perfect and unachievable knowledge of the first group has turned to something more smooth, realistic and achievable. Comparing with the early dialogues that did not set out from the first to reach positive results, the middle ones are extraordinarily and surprisingly positive and hence destroy the basis of the Socratic circle. The questions and answers are purposely directed to some specific new theories; most of them are not directly related to the topics or the main questions of the dialogues. They are suggested when Socrates draws the attention of the interlocutor away from the main question because of the necessity of another discussion. Even if the main question remains unanswered, we have still many positive theories, prominently of metaphysical type. These theories are so abundant and dominant in these dialogues, especially Phaedo and Republic, that one might think that they may appear to be arbitrarily sandwiched in there. This helps dialogues to keep their original Socratic structure while they are suggesting new theories. Hence, the Socratic question of 'what is X?', though is still used to launch the discussion, is loosened and is forgotten for most part of the dialogues. Meno that has first a differently formulated question, 'can virtue be taught?', leads finally to the Socratic question of 'What is virtue?'. Phaedo is dedicated to the demonstration of the immortality of soul and the life after death without having a central Socratic question. The case of Republic is more complicated. The first book, on the one hand, has all the criteria of a Socratic circle: its 'what is justice?' question, Socrates’ strong disavowal (e.g. 337d-e), his rejection of all answers and coming back to the first point without finding out any answer. This Book, considered alone, is a perfect Socratic dialogue, as many scholars regard it as early and separated from other books. The books II-X are, on the other hand, far from implementing a Socratic circle. They have still the 'what is justice?' question as their incentive leading question, but they are, in most of the positive doctrines and methods that encompass the main parts, ignoring the question. Even these books that, I believe, are the farthest discussions from the Socratic circle are so cautious not to break the Socratic structure of the dialogue as long as it is possible. What is changed is not the structure of the dialogue but the ontological and epistemological grounds based on which new theories are suggested. -/- 1. Knowledge of the Good We can clearly see in the second group of dialogues that the KWX principle loses the place it had before in our first group. It is not, of course, rejected, but still we cannot say that it has the same situation. KWX that was based on Socratic question, as we discussed before, was the leading principle of the first Socrates’ epistemology and of the highest position. Other epistemological principles, SK directly and BE indirectly, were relying on Socratic question and therefore on KWX. Such a position does not belong to KWX from Meno on. What makes it different in the second Socrates is another principle that is needed it not only as its complementary principle but also as what is more fundamental. Plato, then, does not reject KWX in this period, but, it seems, he transcends to another more basic principle; a principle we shall call the principle of 'Knowledge of the Good' (KG): -/- KG Knowledge of X requires knowledge of the Good. -/- Whereas all the dialogues of our first group are free from any discuscon about KG, it bears a very important role in the second group so as becomes the superior principle of knowledge in Republic. Trying to solve the problem of teachability of virtue, Socrates says that it can be teachable only if it is a kind of knowledge because nothing can be taught to human beings but knowledge (ἐπιστήμην) (Meno 87c2). The dilemma will be, then, whether virtue is knowledge or not (c11-12) and since virtue is good, we can change the question to: whether is there anything good separate from knowledge (εἰ μέν τί ἐστιν ἀγαθὸν καὶ ἄλλο χωριζόμενον ἐπιστήμης) (d4-5). Therefore, the conclusion will be that if there is nothing good which knowledge does not encompass, virtue can be nothing but knowledge (d6-8). What let us discuss KG as an epistemological principle for the second Secrates is the relation he tries to establish between knowledge and the Good which, though is alongside with the mentioned thesis and the idea of virtue as knowledge, goes much deeper inside epistemology asking to regard the Good as the basis of knowledge. The effort of Phaedo cannot succeed in establishing the Good as the criterion of explanation and knowledge since, I think, it needs a far more complicated ontology of Republic where Socrates can finally announce KG. What is said in Republic is totally compatible with Phaedo 99d–e and the metaphor of watching an eclipse of the sun. In spite of the fact that we do not have adequate knowledge of the Idea of the Good, it is necessary for every kind of knowledge: 'If we do not know it, even if we know all other things, it is of no benefit to us without it' (505a6-7). The problem of our not having sufficient knowledge of the Idea of Good is tried to be solved by the same method of Phaedo 99d-e, that is to say, by looking at what is like instead of looking at thing itself (506d8-e4). It is this solution that leads to the comparison of the Good with sun in the allegory of Sun (508b12-13). What the Good is in the intelligible realm corresponds to what the sun is in the visible realm; as sun is not sight, but is its cause and is seen by it (b9-10), the Good is so regarding knowledge. It has, then, the same role for knowledge that the sun has for sight. Socrates draws our attention to the function of sun in our seeing. The eyes can see everything only in the light of the day being unable to see the same things in the gloom of night (508c4-6). Without the sun, our eyes are dimmed and blind as if they do not have clear vision any longer (c6-7). That the Good must have the same role about knowledge based on the analogy means that it must be considered as a required condition of any kind of knowledge: -/- The soul, then, thinks (νόει) in the same way: whenever it focuses on what is shined upon by truth and being, understands (ἐνόησέν), knows (ἔγνω) and apparently possesses understanding (νοῦν ἔχειν). (508d4-6) -/- Socrates does not use agathon in this paragraph and substitutes it with both aletheia and to on. He links them with the Idea of the Good when he is to assert the conclusion of the analogy: -/- That which gives truth to the objects of knowledge and the power of knowing to the knower, you must say, is the Idea of the Good: being the cause of knowledge and truth (αἰτίαν δ᾽ ἐπιστήμης οὖσαν καὶ ἀληθείας) so far as it is known (ὡς γιγνωσκομένης μὲν διανοοῦ). (508e1-4) Knowledge and truth are called goodlike (ἀγαθοειδῆ) since they are not the same as the Good but more honoured (508e6-509a5). KG, which had been implicitly contemplated and searched in Phaedo, is now explicitly being asserted in Republic. As what was quoted clearly proves, this principle is the very one which we can observe as the most fundamental principle of the second Socrates in Republic, corresponding to the role KWX had in the first Socrates. The Form of the Good in Republic, of which Santas speaks as 'the centerpiece of the canonical Platonism of the middle dialogues, the centerpiece of Plato’s metaphysics, epistemology, ethics and …' (1983, 256) much more can be said. Plato’s Cave allegory in Book VIII dedicates a similar role to the Idea of the Good. The Idea of the Good is there as the last thing to be seen in the knowable realm, something so important that its seeing equals to understanding the fact that it is the cause of all that is correct and beautiful (517b). Producing both light and its source in visible realm, it controls and provides truth and understanding in the intelligible realm (517c). -/- 2. Tripartite Epistemology BE is thoroughy rejected in the second Socrates and substituted by its opposite, the principle of 'Tripartite Epistemolgy' (TE): -/- TE Opinion is an epistemological status between knowledge and ignorance. BE of the first Socrates was denying any third way besides knowledge and ignorance which was the foundation of Socratic circle without which Socrates could not reject his interlocutors’ possessing any kind of knowledge. We cannot say, however, that the first Socrates had a third epistemological status in mind but rejected it. Such a status was unacceptable for him so that one can say that he would reject any kind of such status if suggested. There were only two possibilities about knowledge: either one knows something or he does not know it. TE, thus, was not the first Socrates’ discovery and, I think it is not the second Socrates’discovery. All we can see in our second group of dialouges is that he uses this principle as an already demonstrated one. Having examined the slave boy in Meno for the prupose of showing the working of recollection, it truns out that he has some opinions in him while he still does not know. Without trying to prove it, Socrates takes this as the distinction between knowledge and opinion: -/- So, he who does not know (οὐκ εἰδότι) about what he does not know (περὶ ὧν ἂν μὴ εἰδῇ) has within himself true opinions (ἀληθεῖς δόξαι) about the same things he did not know (περὶ τούτων ὧν οὐκ οἶδε) (85c6-7). -/- The same distinction is set between ὀρθὴν δόξαν and ἐπιστήμην at 97b5-6 ff. (also cf. 97b1-2: ὀρθῶς μὲν δοξάζων … ἐπιστάμενος). He connects then their difference to the myth of Daedalus, the statue that would run away and escape. So are true opinions, not willing to remain long in mind and thus not worthy until one ties them down by αἰτίας λογισμῷ (98a3-4). Socrates says that this tying down is anamnesis. We face, in Phaedo, the same relation is settled between knowledge as the process of being tied down and getting the capability to give an account, on the one hand, and anamnesis, on the other hand. When a man knows, he must be able to give an account of what he knows (Phaedo 76b5-6) and since not all people are able to give such an account, those who recollect, recollect what once they learned (76c4). Although the distinction between knowledge and opinion is not explicitly used in Phaedo, referring to the parallel link between knowledge plus account and anamnesis in Phaedo and Meno, one can say that those who cannot recollect are not able to give account and, thus, are in a state of opinion. What is said at Phaedo 84a, though not yet a definite distinction between knowledge and opinion, makes a distinction between their objects so as we can agree that it is presupposed. The soul of the philosopher, Socrates says, follows reason, stays with it forever and contemplates the divine, which is not the object of opinoin (ἀδόξαστον) (84a8, cf. Meno 98b2-5). The distinction of knowledge and belief in Republic has a significant difference with what we discussed in Meno and Phaedo since the distinction of Meno was based on anamnesis and thus more an epistemological distinction. Even in Phaedo that we do not have any elaborate discussion about the distinction, the only hint to the matter at 76 is bound to the theory of anamnesis. In addition to the relation of the distinction with this theory, there is another evidence that does not permit us to consider the distinction as an ontological distinction. Let’s see Meno 85c6-7: -/- So, he who does not know about what he does not know has within himself true opinions about the same things he did not know (τῷ οὐκ εἰδότι ἄρα περὶ ὧν ἂν μὴ εἰδῇ ἔνεισιν ἀληθεῖς δόξαι περὶ τούτων ὧν οὐκ οἶδε). (85c6-7) -/- This last sentence persists that the objects of knowledge and true opinion are the same. What Socrates is to say here is that whereas he does not know X he has true opinion about the same X. I think Socrates’ sentence that the slave boy οὐκ εἰδότι ἄρα περὶ ὧν ἂν μὴ εἰδῇ and his restatement of it by saying περὶ τούτων ὧν οὐκ οἶδε is because he wants to emphasize that the slave boy who does not know, has true opinion about the same thing. Socrates could say this just with using τούτων and there would be no necessity to bring περὶ ὧν ἂν μὴ εἰδῇ for οὐκ εἰδότι if he did not want to emphasize. -/- 3. Tripartite Ontology The distinction between knowledge and true opinion in Republic, on other side, has nothing to do with recollection, but is based on an ontological principle, 'Tripartite Ontology' (TO): -/- TO There are things that both are and are not. -/- This principle I confine, among our three dialogues of the second group, to Republic not extended to Meno and Phaedo, is obviously the opposite of BO. Speaking about the lovers of sights and sounds in the fifth book, Socrates distinguishes them from philosophers because their thought is unable to understand the nature of beautiful itself besides beautiful things (476a6-8) and hence they can only have opinions. The philosopher who, on the contrary, believes in beautiful itself and can distinguish it from beautiful things (476c9-d3), has knowledge because he knows, contrasting others who have opinion because they only opine (d5-6). Since those whose knowledge were degraded as opinion will complain about Socrates’ such calling their thought, he provides them the following argument (476e7-477b1): -/- - Does the person who knows, knows (γιγνώσκει) something (τὶ) or nothing (οὐδέν)? - He knows something (τί). - Something that is (ὂν) or is not (οὐκ ὄν)? - Something that is (ὂν) for how could something that is not be known (πῶς γὰρ ἂν μὴ ὄν γέ τι γνωσθείη)? - Then we have an adequate grasp of this: No matter how many ways we examine it, what completely is (παντελῶς ὂν) is completely knowable (παντελῶς γνωστόν) and what is in no way (μὴ ὂν δὲ μηδαμῇ) is in every way unknowable (πάντῃ ἄγνωστον). - A most adequate one. - Good. Now, if anything is such as to be and also not to be (ὡς εἶναί τε καὶ μὴ εἶναι), won’t it be intermediate (μεταξὺ) between what purely is (εἰλικρινῶς ὄντος) and what in no way is (μηδαμῇ ὄντος)? - Yes, it’s intermediate. - Then as knowledge (γνῶσις) is set over what is (τῷ ὄντι), while ignorance (ἀγνωσία) is of necessity set over what is not (μὴ ὄντι) mustn’t we find an intermediate between ignorance (ἀγνοίας) and knowledge (ἐπιστήμης) to be set over the intermediate, if there is such a thing? -/- From the third status of being we must reach to the third status of knowledge. The simple reading of this text can be an existential reading, taking the "is" of the mentioned sentences as existence. The problem is that when it is said that there is something that both is and is not reading "is" existentially, it sounds too bizarre to be acceptable. It cannot easily be understandable to have something as both existent and non-existent at the same time. This problem arose so many debates and led many scholars to reject the existential reading of "is" and suggest some other readings like predicative or veridical readings. I think though Plato’s complicated ontology of Republic cannot be correctly understood by a simple existential reading, this "is" cannot be free from existential sense of being and, thus, cannot be reduced to just a predicative or veridical sense of being. -/- 4. Bound Knowledges In addition to KG, the Good is also the basis of another principle in the second Socrates, namely the principle of 'Bound Knowledge' (BK): -/- BK Knowledge of everything is bound to the knowledge of the Good. -/- We distinguished BK from KG because we want to insist, in BK, on what had not been insisted upon in KG, that is, the binding role that the Good plays in the second Socrates, contrasting the absence of such a role in the first Socrates. Socrates remembers, in Phaedo, his wonderful keen on natural philosophers' wisdom when he was young. The origin of this enthusiasm was Socrates’ hope to know the cause of everything as they used to claim. When he was searching the matters of his interest on their basis, Socrates says, he became convinced he can get no acceptable answer from them and found himself blind even to the things he thought he knew before. One day he hears Anaxagoras’ theory that 'it is Mind that arranges and is the cause of everything (ὡς ἄρα νοῦς ἐστιν ὁ διακοσμῶν τε καὶ πάντων αἴτιος)' (Phd. 97c1-2 cf. DK, Fr.15.8-9, 11-12, 12-14) and thinks that he can finally find what he has always expected, i.e. something which can explain all things. What I intend to show here is that what makes Socrates hopeful is that Anaxagoras’ theory tries 1) to explain all things by one thing and 2) this explanation is understood by Socrates as if it is based on the concept of the Good. That Socrates was searching for one explanation for all things can be proved even from what he has been expecting from natural philosophers. The case is, nonetheless, more clearly asserted when he speaks about Anaxagoras’ theory. In addition to διακοσμῶν τε καὶ πάντων αἴτιος of 97c2 mentioned above, we have τὸ τὸν νοῦν εἶναι πάντων αἴτιον (c3-4) and τόν γε νοῦν κοσμοῦντα πάντα κοσμεῖν (c4-5) all emphasizing on the cause of all things (πάντα) which can clearly prove that one of the reasons which caused Socrates to embrace it delightfully was its claim to provide the cause of all things by one thing. Another reason was that Anaxagoras’ Mind, at least in Socrates’ view, was attempting to explain everything by the concept of the Good. This connection between Mind and Good belongs more to the essential relation they have in Socrates’ thinking than Anaxagoras’ theory because there are almost nothing about such a relation in Anaxagoras. The reason for Socrates’ reading can be that Mind is substantially compatible with Socrates’ idea of the relation between good and knowledge. Both the thesis 'no one does wrong willingly' and the theory of virtue as knowledge we pointed to above are evidences of this essential relation. Nobody who knows that something is bad can choose or do it as bad. The reason, when it is reason, that means when it is as it should be, when it is wise or when it knows, works only based on good-choosing. In this context, when Socrates hears that Mind is considered as the cause of everything, it sounds to him like this: good should be regarded as the basis of the explanation of all things. We see him, thus, passing from the former to the latter without any proof. This is done in the second sentence after introducing Mind: -/- I thought that if this were so, the arranging Mind would arrange all things and put each thing in the way that was Best (ὅπῃ ἂν βέλτιστα ἔχῃ). If one then wished to find the cause of each thing by which it either perishes or exists, one needs to find what is the best way (βέλτιστον αὐτῷ ἐστιν) for it to be, or to be acted upon, or to act. On these premises then it befitted a man to investigate only, about this and other things, what is the most excellent (ἄριστον) and best (βέλτιστον). The same man must inevitably also know what is worse (χεῖρον), for that is part of the same knowledge. (97c4-d5) This passage is a good evidence of Socrates’ leap from Anaxagoras’ Mind to his own concept of the Good that can explain why Socrates found Anaxagoras theory after his own heart (97d7). Mind is welcomed because of its capability for explanation on the basis of good to 'explain why it is so of necessity, saying which is better (ἄμεινον), and that it was better (ἄμεινον) to be so' (97e1-3). What Socrates thought he had found in Anaxagoras can indicate what he had been expecting from natural scientists before. Socrates could not be satisfied with their explanations because they were unable to explain how it is the best for everything to be as it is. It can probably be said, then, that it was the lack of the unifying Good in their explanation that had disappointed him. We must insist that we are discussing what Socrates thought that Anaxagoras’ theory of Mind should have been, not about Anaxagoras’ actual way of using Mind. Phaedo 97c-98b, is not about what Socrates found in Anaxagoras but what he thought he could find in it. On the contrary, it should also be noted that it was not this that was dashed at 98b, but Anaxagoras’ actual way of using Mind. It was Anaxagoras’ fault not to find out how to use such an excellent thesis (98b8-c2, cf. 98e-99b). Socrates gives an example to show how not believing in 'good' as the basis of explanation makes people be wanderers between different unreal explanations of a thing. His words δέον συνδεῖν (binding that binds together) as a description for the Good we chose as the name of BK principle: They do not believe that the truly good and binding binds and holds them together (ὡς ἀληθῶς τὸ ἀγαθὸν καὶ δέον συνδεῖν καὶ συνέχειν οὐδὲν οἴονται). (99c5-6) -/- Having in mind Plato’s well-known analogy of the sun and the Good at Republic 508-509, we can dare to say that his warning of the danger of seeing the truth directly like one watching an eclipse of the sun in Phaedo (99d-e) is more about the difficulty of so-called good-based explanation than its insufficiency, a difficulty which is precisely confirmed in Republic (504e-505a, 506d-e). Moreover, BK is asserted in a more explicit way in the Republic, where the Good is considered not only as a condition for the knowledge of X, as was noted above discussing KG, but also as what binds all the objects of knowledge and also the soul in its knowing them. At Republic VI, 508e1-3, when Socrates says that the Form of the Good 'gives truth to the things known and the power to know to the knower (τοῦτο τοίνυν τὸ τὴν ἀλήθειαν παρέχον τοῖς γιγνωσκομένοις καὶ τῷ γιγνώσκοντι τὴν δύναμιν ἀποδιδὸν)', he wants to set the Good at the highest point of his epistemological structure by which all the elements of this structure are bound. This binding aspect of the Good is by no means a simple binding of all knowledges or all the objects of knowledge, but the most complicated kind of binding as it is expected from the author of the Republic. The kind of unity the Good gives to the different knowledges of different things is comparable with the unity which each Form gives to its participants in Republic: as all the participants of a Form are united by referring to the ideas, all different kinds of knowledge are united by referring to the Good. If we observe Aristotle's assertion that for Plato and the believers of Forms, the causative relation of the One with the Forms is the same as that of the Forms with particulars (e.g. Metaphysics 988a10-11, 988b4), that is to say the One is the essence (e.g., ibid, 988a10-11: τοῦ τί ἐστὶν, 988b4-6: τὸ τί ἢν εἶναί) of the Forms besides his statement that for them One is the Good (e.g., ibid, 988b11-13) the relation between the Good and unity may become more understandable. Since the quiddity of the Good (τί ποτ᾽ ἐστὶ τἀγαθὸν) is more than discussion (506d8-e2), we cannot await Socrates to tell us how this binding role is played. All we can expect is to hear from him an analogy by which this unifying role is envisaged, the sun. The kind of unity that the Good gives to the knowledge and its objects in the intelligible realm is comparable to the unity that the sun gives to the sight and its objects in the visible realm (508b-c). The allegory of Line (Republic VI, 509d-511), like that of the Sun, tries to bind all various kinds of knowledges. The hierarchical model of the Line which encompasses all kinds of knowledge from imagination to understanding can clearly be considered as Plato’s effort to bind all kinds of knowledges by a certain unhypothetical principle. The method of hypothesis starts, in the first subsection of the intelligible realm, with a hypothesis that is not directed firstly to a principle but a conclusion (510b4-6). It proceeds, in the other subsection, to a 'principle which is not a hypothesis' (b7) and is called the 'unhypothetical principle of all things' (ἀνυποθέτου ἐπὶ τὴν τοῦ παντὸς ἀρχὴν) (511b6-7). This παντὸς must refer not only to the objects of the intelligible realm but to the sensible objects as well. Plato does posit, therefore, an epistemological principle for all things, a principle that all things are, epistemologically, bound and, thus, unified by. -/- 5. Bound Beings The ontological aspect of BK we shall call the principle of 'Bound Beings' (BB): -/- BB Being of all things are bound by the Good. -/- We saw in our principle of Split Being (SB) how the first Socrates was criticized because of his approach to split being and separate each thing from other things. The principle of Bound Beings intends to make the things more related, a duty which is done again by the Good. In the allegory of Sun, there are two paragraphs that evidently and deliberately extend the binding role of the Good to the ontological scene: -/- You will say that the sun not only makes the visible things have the ability of being seen but also coming to be, growth and nourishment. (509b2-4) -/- This clearly intends to remind the ontological role the sun plays in bringing to being all the sensible things in order to display how its counterpart has the same role in the intelligible realm (b6-10): -/- Not only the objects of knowledge (γιγνωσκομένοις) owe their being known (γιγνώσκεσθαι) to the Good, but also their existence (τὸ εἶναί) and their being (οὐσίαν) are due to it, though the Good is not being but superior to it in rank and power. That the Good is here represented as responsible for being of things in addition to their being known means, in my opinion, that Plato wants to posit BB in addition to BK. The allegory of Cave at the very beginning of the seventh Book (514aff.) can be taken as another evidence. The role of the Good, one might say, is confined to the intelligible realm because it is asserted that the role the Good plays in this realm is corresponding to that of the sun in the visible realm. The fact that Plato wants to observe the Good also as the ontological cause of the sensible things is obvious from his saying, in the allegory of Cave, that the Form of the Good 'produces light and its source (τὸν τούτου κύριον) [i.e. the sun] in the visible realm' (517c3). We can conclude, then, that the ontological function of the Good is not confined to the intelligible realm in which it is the lord and provides truth and understanding (c3-4) because it is also responsible to produce τὸν κύριον of light. 6. Proportionality of Being and Knowledge Insofaras BE and BO principles of the first Socrates gave way to TE and TO principles of the second Socrates, we cannot expect him to preserve KB in the same way as it was in the first Socrates. The new tripartite ontology and epistemology necessitates some modifications in KB which results in the principle of 'Proportionality of Being and Knowledge' (PBK): -/- PBK To every class of being there is a proportionate category of knowledge. -/- This principle, of course, does not entail the refutation of KB and thus is not kind of rejecting PBK but only a more complicated version of it. Based on PBK, we can still agree that knowledge is of being (KB) but the issue is that since none of the concepts of knowledge and being in the second Socrates are as simple as they were for the first Socrates, we need a more complicated principle for their relation here. Although from Meno 97a where the distinction of knowledge and true opinion is drawn out in the second group of the dialogues, we can expect a new relation, it is articulated in its most complete way in Republic and specifically in the allegory of Line. All the beings are divided there hierarchically to four classes, to each of them belongs a class of knowledge: imagination to images, belief to the sensible things (more correctly: the things of which they[in previous class] were images (ᾧ τοῦτο ἔοικεν)), thought to mathematical objects (?) and understanding to the Forms and the first principle. The degree of clarity that each of the classes of knowledge shares in (σαφηνείας ἡγησάμενος μετέχειν) is proportionate to the degree that its object shares in truth (ἀληθείας μετέχει). (511e2-4) -/- Conclusion From the six onto-epistemilogical principles of the first Socrates, four principles turn to their opposite in the middle period dialogues. While bipolar epistemology and ontology of the early dialogues give place to tripartite epistemology in the middle period dialogues and tripartite ontology in Republic, the split knowledge and being of the first Socrates are inclined to be substituted by bound knowledges and bound beings in the second Socrates and specifically in Republic. Not all our system of principles in this article is necessarily determinative. Either they are rightly formulated or not, our result would not be vulnerable if we accept that 1) making the distinction of knowledge and belief, 2) accepting the being of not being and 3) trying to bind both being and knowledge by the concept of the Good happens only in middle period dialogues, having been absent in the early ones. These are the favourite results all those somehow arbitrary and even oversimplified principles were to illustrate; that there is kind of a development in the epistemological as well as the ontological grounds of Plato’s philosophy. -/- Notes . (shrink)

FISIOLOGIA DO PARTO E DA LACTAÇÃO ANIMAL -/- ANIMAL REPRODUCTION: PHISIOLOGY OF PARTURITION AND ANIMAL LACTATION -/- Emanuel Isaque Cordeiro da Silva Departamento de Zootecnia da UFRPE WhatsApp: (82)98143-8399 -/- 1. INTRODUÇÃO O sucesso biológico do processo de reprodução culmina com a sobrevivência das crias. Durante a gestação, o feto desenvolve-se no útero materno protegido das influências externas, e obtendo os nutrientes e o oxigênio através da mãe. O parto é o processo biológico que marca o fim da gestação e (...) o início da vida extrauterina do animal. Para garantir a sobrevivência do recém-nascido o parto deve ser um processo controlado para que se inicie unicamente quando o feto tiver alcançado desenvolvimento suficiente que lhe permita enfrentar a vida extrauterina. Após o nascimento, a secreção de leite pela glândula mamária proporciona ao neonato tanto os nutrientes necessários para seu desenvolvimento como as defesas (imunoglobulinas) que lhe protegerão contra as possíveis infecções durante as primeiras fases de sua vida. Parto e lactação constituem a última etapa de um ciclo reprodutivo completo nas fêmeas dos animais domésticos, estando ambos os processos regulados e sincronizados por complexas mudanças hormonais na mãe. Estas mudanças são, em última análise, provocadas e governadas pelo próprio feto ou recém-nascido, o qual acomoda as respostas maternas às suas necessidades garantindo a sua sobrevivência. 2. O PARTO O parto é definido como o processo fisiológico pelo qual ocorre a expulsão de um ou mais fetos maduros, bem como das membranas fetais existentes no útero materno. Este processo é desencadeado por uma interação complexa entre as hormonas maternas (fatores maternos) e fetais (fatores fetais). Para que se realize a expulsão do feto é necessário que o útero deixe de ser um órgão quiescente, essencial para a manutenção da gestação, para ser um órgão contrátil. Ao mesmo tempo, o cérvix ou colo uterino, que durante a gestação permanece firmemente fechado para impedir a expulsão prematura do feto e evitar a entrada de agentes infecciosos, relaxa e dilata para facilitar a passagem do feto na hora do parto. Esta modificação na atividade do útero e do colo uterino, ocorrem como consequência das mudanças hormonais que o organismo materno experimenta à medida que a data do parto se aproxima. 2.1 Fatores maternos A gestação dos animais domésticos ocorre com elevada concentração de progesterona que, dependendo da espécie animal, é secretada seja pelo corpo lúteo do ovário (vaca, porca e cabra) ou pela placenta (ovelha e égua). A progesterona desempenha um papel fundamental durante a gestação, inibindo as contrações da musculatura lisa do útero (miométrio), permitindo assim a acomodação do feto durante o seu crescimento. Os estrogênios, estimulantes da atividade contrátil do miométrio, mantêm-se a baixas concentrações durante a maior parte da gestação. À medida que se aproxima o momento do parto, os níveis destes hormônios esteroides modificam-se, produzindo-se a diminuição nos níveis circulantes da progesterona ao mesmo tempo que se incrementam os valores sanguíneos dos estrogênios (figura 1). A redução dos níveis de progesterona suprime a sua ação inibitória sobre a atividade contrátil do miométrio, permitindo que se manifestem os efeitos estimulantes dos estrogênios sobre este órgão. A concentração de estrogênios começa a aumentar geralmente no final da gestação, atingindo os seus valores máximos no momento do parto (figura 1). O aumento da concentração de estrogênios favorece a atividade contrátil espontânea do útero ao: a) estimular a síntese de proteínas contráteis; b) aumentar, sob medida, a sensibilidade do miométrio uterino à ação estimulante das prostaglandinas; c) induzir a formação de receptores de oxitocina no útero. -/- Figura 1. Níveis de progesterona e estrógenos durante a gestação e parto das espécies ovina, caprina, suína e bovina. Fonte: HAFEZ, 2013. Os estrogênios estimulam a síntese e secreção de prostaglandina (PGF2a), que constitui o elemento essencial para o início do parto devido aos efeitos que esta substância provoca. Assim, nas fêmeas, cujos níveis de progesterona gestacional dependem da presença do corpo lúteo, a secreção de PGF, origina a regressão deste (luteólise), com a consequente diminuição da progesterona a níveis basais. Além disso, a PGF2a origina contrações de crescente intensidade no útero sensibilizado pela ação dos estrogênios. Esta ação contrátil da PGF2a deve-se a um aumento da concentração de cálcio intracelular das fibras musculares uterinas. A PGF2a também está envolvida no relaxamento do colo do útero, inibindo a formação de colágeno cervical ao mesmo tempo que estimula a síntese de enzimas (colagenase) que degradam a matriz de colágeno formado no início da gestação. A dilatação do colo do útero está também associada à pressão que o feto exerce sobre o mesmo e, no caso da porca, a relaxina pode também estar envolvida. Esta hormona é também de grande importância para a preparação do parto em todas as espécies animais, uma vez que é responsável pelo relaxamento dos ligamentos e músculos que rodeiam o canal pélvico para favorecer a separação da sínfise púbica durante a expulsão do feto. Nos grandes animais (vaca, égua) as mudanças que ocorrem nos tecidos e ligamentos pélvicos são muito evidentes e constituem um sintoma de parto iminente. O início do parto, ou primeira fase do parto, caracteriza-se pelo aumento das contrações uterinas provocadas pela PGF2a coincidindo com a dilatação do colo uterino para permitir a passagem do feto para o canal do parto, momento em que começa a segunda fase do parto. A distensão vaginal que produz-se para a passagem do feto pelo canal do parto origina um estímulo nervoso que viaja através da medula espinal para o hipotálamo, onde se encontram os neurônios responsáveis pela síntese de oxitocina. As terminações nervosas destes neurónios são projetadas para o lobo posterior da hipófise (neurohipófise), onde a oxitocina é secretada para ser, posteriormente , transportada pela circulação sanguínea. Este reflexo neuroendócrino chamado reflexo de Ferguson determina a secreção súbita de oxitocina, provocando o aumento tanto na intensidade como na frequência das contrações uterinas necessárias para a expulsão final do feto. O papel da oxitocina é ativar a conclusão do processo de expulsão, uma vez que esta hormona não está envolvida no início do parto. A alteração mais significativa entre a gestação e o parto é a alteração na atividade contrátil do miométrio uterino. Esta mudança é devido às alterações hormonais que ocorrem na mãe quando a gestação chegou a fim. No entanto, para que estes mecanismos maternos sejam acionados, é necessário que o feto indique de alguma forma à mãe o seu estado de desenvolvimento, de modo que o nascimento realize-se quando o feto estiver preparado para enfrentar a vida extrauterina. 2.2 Fatores fetais A destruição experimental da hipófise e/ou das glândulas adrenais do feto origina o prolongamento da gestação nos animais domésticos. Pelo contrário, a administração exógena de cortisol (corticosteroides adrenais), ou do seu precursor hipofisário (ACTH), à circulação fetal provoca, em poucas horas, o início do parto. Estes fatos evidenciam a importância do eixo hipófise-adrenal do feto para desencadear o início do parto (figura 2). Figura 2. Mecanismos fetais que controlam o parto em ovelhas. Fonte: LIGGINS et al, 1972. No final da gestação, o feto maduro apresenta um aumento da concentração de corticosteroides plasmáticos devido ao efeito estimulante da hormona adrenocorticotróide (ACVH) secretada pela hipófise fetal sobre as glândulas adrenais do feto. Os corticosteroides fetais por sua vez estimulam as enzimas placentárias para transformar a progesterona em estrogênio. O resultado final é a diminuição dos níveis de progesterona ao mesmo tempo que se eleva a concentração de estrogênios que, por sua vez, estimulam a libertação de PGF2a responsável pelas contrações uterinas. Este raciocínio explica algumas doenças caracterizadas por gestação prolongada em ovelhas, como ocorre na África do Sul, onde estes animais são obrigados, durante as épocas de seca, a ingerir as folhas de um arbusto chamado Salsola tuberculate. O prolongamento da gestação ocorre quando estas folhas são ingeridas durante o último terço da gestação cujos efeitos estão relacionados com a supressão do eixo hipotálamo-hipófise, com o qual as adrenais não recebem o estímulo necessário (ACTH) para a síntese e liberação de corticoides. O efeito contrário é observado nas cabras da raça Angorá, nas quais se produzem, com relativa frequência, partos prematuros que podem estar relacionados com um desenvolvimento precoce das glândulas adrenais. Isto significa que, nos animais domésticos, o feto determina a data do parto. O sinal hormonal que indica à mãe o grau de maturidade do feto é o desenvolvimento do eixo hipotálamo-hipófise-adrenal que origina o aumento na secreção de corticoides fetais que são os responsáveis por desencadear as alterações hormonais no organismo materno necessárias para iniciar o parto. A figura 2 mostra como a remoção da hipófise e as adrenais do feto prolongam a gestação, enquanto a administração exógena de ACTH ou corticoides (cortisol) ao feto originam um parto prematuro. O momento em que ocorre o aumento da concentração plasmática de corticoides no feto varia de acordo com a espécie: de 25 a 30 dias antes do parto na vaca, de 7 a 10 dias na porca e de 2 a 3 dias na ovelha. 2.3 Desenvolvimento e fases do parto O parto inicia-se com o início das contrações peristálticas e regulares do miométrio uterino ao mesmo tempo que o colo do útero se dilata progressivamente. Nas fêmeas que gestam um único feto (monotecas), as contrações começam na extremidade anterior do córneo uterino, enquanto que nas espécies que gestam vários fetos (politocas) as contrações começam pela extremidade cervical para começar a expulsar o feto que se encontra mais próximo do cérvix. Durante o parto são reconhecidas três fases: 1. Fase preparatória - Na qual as contrações uterinas estimulam a rotação do feto (fêmeas monotecas) para adotar a posição dorsal (extremidades anteriores e cabeça forçadas contra o cérvix) que lhe permite oferecer a menor resistência para sua expulsão. A PGF2a provoca as contrações miometriais e a dilatação do cérvix, deslocando o feto contra e através desta estrutura. 2. Fase de expulsão - A passagem do feto através do colo uterino e da vagina causam a completa dilatação destas estruturas, originando a secreção de oxitocina (reflexo de Ferguson), que provoca contrações de maior frequência e intensidade. Por sua vez, estas contrações uterinas são reforçadas pela pressão e contração dos músculos abdominais, chegando estes últimos a ser a força principal (forças de expulsão) envolvida no processo de expulsão do feto. O cordão umbilical rompe-se bem ao levantar-se a mãe ou pelos movimentos do recém-nascido. 3. Fase de expulsão da placenta - Após o parto, as contrações rítmicas do útero continuam a facilitar a expulsão da(s) placenta(s). O tempo necessário para este processo varia de acordo com a espécie animal. Este processo é rápido na égua, já que a separação do corion (membrana fetal) de sua inserção uterina ocorre durante a expulsão do feto, com o qual o parto deve ser concluído rapidamente ou, caso contrário, o potro se asfixiaria. Nos ruminantes, a expulsão da placenta cotiledonaria é um processo mais lento que exige a separação dos cotilédones (membrana fetal) das carúnculas do útero. Por conseguinte, a troca de nutrientes e oxigênio entre a mãe e o feto continua até que este tenha sido totalmente expelido, devido ao cordão umbilical destes animais ser bastante longo. Nas fêmeas politocas, como a porca, geralmente as placentas de vários leitões são expulsadas no final, quando os leitões já foram expelidos, se bem que o último leitão poderá ser expelido durante a expulsão da massa placentária. 3. LACTAÇÃO A lactação constitui o processo que define os mamíferos como classe biológica. O desenvolvimento pós-natal dos mamíferos vai depender, em grande medida, dos nutrientes e defesas fornecidos pela mãe através da secreção de leite (imunoglobulinas). Assim, uma vez concluído o desenvolvimento gestacional do feto, a glândula mamária irá substituir, de certa forma, a função nutritiva e protetora da placenta durante a gestação. 3.1 Anatomia funcional da glândula mamária A estrutura funcional da glândula mamária é muito semelhante em todos os mamíferos, embora o tamanho, forma e número de glândulas varia dependendo da espécie animal. As glândulas mamárias desenvolvem-se como estruturas pares cujo número varia de um par (égua, cabra e ovelha), dois pares (vaca) até sete ou nove (porca). A localização das glândulas também difere sendo inguinal em vaca, égua, cabra e ovelha, enquanto que na porca, cadela e gata se estendem por todo o comprimento do tórax e abdômen. Nos animais domésticos em geral as glândulas mamárias recebem o nome de úberes. Tomando como modelo a vaca, a glândula mamária se organiza em duas estruturas: o estroma, formado por tecido conjuntivo procedente dos ligamentos suspensório medial, localizado entre os dois pares de glândulas, dando suporte à segunda estrutura que é o tecido secretor. Este é formado por acúmulos de células secretoras formando estruturas ocas chamadas alvéolos, que são as unidades fundamentais secretoras de leite. Os alvéolos estão circulados internamente por células epiteliais (secretoras) e rodeados externamente por células mioepiteliais contráteis, cuja contração origina a ejeção do leite (figura 3). O agrupamento de vários alvéolos adjacentes formam um lobo secretor. Figura 3. Diagrama de um agregado de alvéolos na glândula mamária de uma cabra. Fonte: COWIE et al, 1980. Os lobos expelem a secreção através de ductos que, por sua vez, drenam os ductos galactóforas (ductos lácteos) de maior diâmetro, para desembocar em áreas especializadas em armazenar o leite chamadas cisternas (vaca, cabra). Finalmente, a cisterna abre-se para o exterior através do canal papilar da teta. A presença do músculo liso na teta permite-lhe agir como esfíncter para impedir que o leite seja expelido passivamente do interior da glândula. O mamilo/teta é provido de numerosos receptores sensitivos cuja excitação durante a ordenha ou amamentação vai desencadear estímulos nervosos de grande importância para a manutenção da lactação. 3.2 Desenvolvimento da glândula mamária (mamogênese) A glândula mamária difere das demais glândulas do organismo no escasso desenvolvimento que apresenta no nascimento da fêmea, o qual não se inicia até que esta não atinja a puberdade. O início da atividade cíclica do ovário (puberdade) dá origem à síntese de estrogênios (fase folicular do ciclo estral) e progesterona (fase lútea). Os estrogênios originam o alongamento e ramificação dos ductos e a formação de pequenas massas esféricas de células (os futuros alvéolos). Embora este desenvolvimento seja dependente do estrogênio, é também necessária a ação sinérgica da prolactina, hormona do crescimento (GH) e corticoides adrenais, como demonstrado pelos estudos realizados em ratos aos quais foi removida a hipófise, glândulas suprarrenais e ovários (figura 4). A função da progesterona no desenvolvimento da glândula mamária é estimular o crescimento do lobo-alveolar, mas como no caso anterior também requer a ação conjunta dos hormônios acima mencionados. Figura 4. Hormonas relacionadas com o crescimento da glândula mamária e início da secreção de leite na rata hipofisectomizada-adrenoectomizada-ovariectomizada. Fonte: COWIE, 1980. O desenvolvimento da glândula, durante cada ciclo estral, vai depender da duração da fase folicular (níveis elevados de estrogênio), já que nas restantes fases do ciclo, quando os níveis de estrogênio são baixos, os ductos sofrem uma ligeira regressão. Nas espécies com ciclos curtos (rata), em que a fase folicular do ciclo é predominante, enquanto a fase lútea é quase inexistente, verifica-se um grande desenvolvimento dos ductos; enquanto que aquelas que apresentam um corpo lúteo funcional de longa duração (cadela e primatas), além do crescimento dos ductos, mostram um grande desenvolvimento lóbulo-alveolar semelhante ao que ocorre na gestação. É durante a gestação que o sistema alveolar sofre uma hipertrofia considerável, resultando em lobos proeminentes e no desenvolvimento da luz interna dos alvéolos, fato que é evidente na maioria dos animais domésticos por volta da metade do período gestacional. Em algumas espécies, as células que circundam interiormente os alvéolos contêm produtos secretores, indicando que a glândula mamária já está preparada para a fase da lactação. O desenvolvimento glandular durante a gestação deve-se ao efeito conjunto da progesterona e dos estrogênios com as hormonas hipofisárias acima mencionadas: prolactina, hormona do crescimento (GH) e adrenocorticotropina (ACTH). A proporção entre estrogênios e progesterona varia de acordo com a espécie, mas geralmente é necessária uma maior concentração de progesterona (proveniente do corpo lúteo ou da placenta). Quanto às hormonas hipofisárias, a prolactina desempenha um papel fundamental na diferenciação da glândula mamária (mesmo a baixas concentrações) ao estimular o desenvolvimento do epitélio secretor dos alvéolos. A GH favorece o crescimento dos ductos e a ACTH estimula a secreção de corticoides nas adrenais que, por sua vez, favorecem de forma generalizada o crescimento das glândulas. 3.3 Secreção da glândula mamária (lactogênese) A lactogênese, ou o processo pelo qual se produz a síntese e secreção do leite pela glândula mamária, começa no final da gestação coincidindo com o desencadeamento do parto. O primeiro leite formado imediatamente antes ou depois do parto é denominado colostro. No entanto, a lactação não pode desenvolver- se completamente até que se inicie o processo de parto. Isto deve-se ao fato de que o processo de lactação resulta de uma interação complexa de hormonas que preparam a glândula mamária para a secreção do leite. Os requisitos hormonais mínimos para o início da lactogênese são: aumento da secreção de estrogênios, prolactina e corticoides, juntamente com a diminuição da concentração de progesterona, perfis hormonais que estão intimamente relacionados com o desencadeamento do parto. Isto deve-se ao fato de que a progesterona inibe a atividade lactogênica da prolactina bloqueando a formação dos seus receptores na glândula mamária durante a gestação impedindo, assim, a prolactina de sintetizar os componentes fundamentais do leite. Pelo contrário, o aumento da concentração de estrogênios no final da gestação (figura 1, na seção do parto) estimula a síntese, o armazenamento e a secreção hipofisária de prolactina. Assim, apesar da glândula mamária estar preparada para iniciar a secreção de leite, muito antes da data prevista para o parto, a elevada concentração de progesterona (existente durante esse período de gestação) impede a fase láctea (saída do leite pelas tetas) de ocorrer antes da expulsão do feto. Desta forma, o feto poderá beneficiar das vantagens que o fornecimento do colostro materno irá trazer para a sua sobrevivência (imunização, nutrição e favorecimento da exoneração do mecônio). O aumento da concentração de estrogênios nos dias que antecederem o parto resulta num rápido aumento das concentrações plasmáticas de prolactina e corticoides. A prolactina é a hormona lactogênica mais importante na síntese dos componentes do leite. No entanto, para que esta hormona possa exercer a sua função, é necessária a participação dos corticoides, já que os mesmos são os responsáveis pelo desenvolvimento das organelas citoplasmáticas (retículo endoplasmático rugoso e aparelho de Golgi) onde se realiza a síntese do leite. No desenvolvimento da lactogênese, para além da prolactina e dos corticoides, participam também outras hormonas como a insulina, a tiroxina e o hormônio do crescimento. A insulina estimula a proliferação de novas células epiteliais na glândula mamária, enquanto a tiroxina, embora não seja essencial para a lactação, pode influenciar no volume de leite produzido pela fêmea (alta produção leiteira). Por último, a hormona do crescimento favorece, em geral, a lactação, existindo atualmente um interesse considerável no uso desta hormona para promover a produção adicional de leite em vacas através da sua administração exógena (trabalho e projeto desenvolvido pela professora titular e médica-veterinária do IFPB Campus Sousa Marianne Christina Velaqua). 3.3.1 Síntese e secreção dos componentes do leite Os principais constituintes do leite são: proteínas (caseína, alfa-lactalbumina, albumina sérica e imunoglobulinas), açúcares (lactose), gorduras (principalmente sob a forma de triglicerídeos), vitaminas, minerais e citrato (no caso dos ruminantes). As proteínas (caseína e alfa-lactalbumina) são sintetizadas no retículo endoplasmático rugoso e posteriormente embaladas em vesículas secretoras do aparelho de Golgi para serem liberadas da célula para a luz alveolar mediante um processo de exocitose. A lactose é o principal açúcar do leite que, além disso, atua regulando a pressão osmótica do mesmo de modo que o volume de leite que a glândula mamária segrega está diretamente relacionado com a quantidade de lactose presente. A síntese da lactose ocorre no aparelho de Golgi pela condensação de glicose e galactose; esta reação é catalisada por uma enzima (lactose sintetase) presente na membrana do aparelho de Golgi que, por sua vez, é ativada pela proteína alfa-lactalbumina. Esta proteína só aparece na glândula mamária e é essencial para a síntese da lactose, o que demonstra que este açúcar é exclusivamente formado no leite. A lactose é também embalada junto com o cálcio, o fosfato e as proteínas nas vesículas secretoras para ser expulsada ao lúmen alveolar por exocitose. As imunoglobulinas (anticorpos IgA) são formadas pelas células plasmáticas, derivadas dos linfócitos B do sangue, como consequência da exposição da mãe a diferentes microrganismos. Estes anticorpos passam para a glândula mamária por migração dessas células a partir dos tecidos adjacentes. Os triglicerídeos são sintetizados no citoplasma e no retículo endoplasmático liso a partir de ácidos graxos provenientes da circulação sanguínea; em seguida, unem-se formando glóbulos de gordura que se dirigem até o vértice da membrana plasmática para serem finalmente expelidos para a luz do alvéolo, rodeados pela membrana, formando assim uma dispersão de glóbulos de gordura (figura 5). Figura 5. Estrutura de três células alveolares durante a síntese do leite. Fonte: COWIE, 1980. Do ponto de vista quantitativo, a caseína e os triglicerídeos constituem as proteínas e as fontes de energia, respectivamente, mais importantes do leite. Por último, o citrato é um intermediário do metabolismo da glicose que ocorre em grande concentração no leite dos ruminantes. Este composto é também englobado no interior das vesículas secretoras, junto com os outros compostos, para sua expulsão à luz alveolar. A composição do leite varia dependendo da espécie animal, e difere também até entre a mesma espécie. Estas variações estão relacionadas com a raça, idade, estágio de lactação e estado nutricional do animal. O teor de gordura no leite de ovelhas, porcas, cadelas e gatas varia entre 7 e 10%. No gado leiteiro estes valores variam de 3,5 a 5,5%, dependendo da raça. Em relação às cabras, os valores de gordura são muito semelhantes aos das vacas, enquanto o leite das éguas é o que tem menor teor de gordura (tabela 1). Espécie Gordura Proteína Lactosa Cinzas/Cálcio Gata 7,1 10,1 4,2 0,5 Vaca holandesa 3,5 3,1 4,9 0,7 Cadela 9,5 9,3 3,1 1,2 Cabra 3,5 3,1 4,6 0,8 Égua 1,6 2,4 6,1 0,5 Tabela 1. Composição do leite em várias espécies (%). Fonte: JACOBISON, 1984. 3.4 Manutenção da lactação (galactopoiese) A capacidade da glândula mamária de secretar um grande volume de leite começa em/ou imediatamente antes do parto, para aumentar no período pós-parto durante um tempo variável e, posteriormente, diminuir de forma gradual. Em geral, existe um paralelismo entre a atividade secretora da glândula e a procura de leite por parte do lactente. Isto deve-se ao fato de sucção pelo lactente, ou a extração por ordenha, que constituem o fator fundamental para a manutenção da lactação. A sucção estimula a lactação de duas formas: a) reduzindo os efeitos inibitórios da pressão intramamária produzida pela acumulação de leite, e b) estimulando intensamente a secreção de hormonas necessárias para manter a síntese e secreção de leite nos alvéolos. As hormonas que desempenham um papel fundamental na manutenção da lactação são: I) a prolactina, que é responsável pela estimulação da síntese e secreção de leite nas células epiteliais nos alvéolos, e 2) a oxitocina, que provoca a contração das células musculares que circundam externamente os alvéolos e os ductos (células mioepiteliais). A libertação de ambos os hormônios ocorre como resultado de um reflexo neuroendócrino originado pela estimulação do mamilo. 3.4.1 Secreção reflexa de prolactina A secreção de prolactina é regulada por dois fatores hipotalâmicos: a dopamina, que inibe a secreção de prolactina e um fator cuja identidade não está bem definida, conhecido como fator liberador de prolactina (PRF)que estimula a liberação deste hormônio. O estímulo sensorial originado como sequência da estimulação do mamilo, pela sucção do lactente, é transportado através da medula espinhal para o hipotálamo, onde atua na inibição da dopamina ou estimulando a secreção do PRF para desencadear a secreção de prolactina da adenohipófise para a circulação sanguínea (figura 6). Figura 6. Reflexos neuroendócrinos secretores de prolactina e oxitocina. Fonte: HAFEZ, 2000. A prolactina estimula a secreção dos componentes do leite para a luz dos alvéolos, afim de repor o volume de leite extraído durante a última ordenha ou sucção. Ao mesmo tempo, a prolactina induz a síntese das proteínas, incluindo a alfa-lactalbumina para estimular novamente a síntese da lactosa, bem como as enzimas necessárias para a produção dos triglicerídeos. Desta forma, a secreção de prolactina originada pelo lactente durante o aleitamento proporciona um mecanismo simples para combinar o volume de produção de leite com as necessidades do lactente. A quantidade de prolactina liberada durante cada período de sucção depende do número de crias, da duração do estímulo e dos intervalos de tempo decorridos entre os períodos de sucção (ou ordenha). No caso das vacas leiteiras, as ordenhas são geralmente realizadas de doze em doze horas, intervalo de tempo suficiente para manter a lactogênese. Os valores plasmáticos de prolactina aumentam imediatamente após o início da ordenha, mas os valores mais elevados são obtidos cerca de meia hora após o início do estímulo (ordenha ou sucção). A secreção de prolactina e a produção de leite são influenciadas de alguma forma pelo fotoperíodo, uma vez que, em alguns animais se comprovou como o aumento do número de horas de exposição à luz dá origem a um aumento da concentração de prolactina circulante, bem como uma maior produção de leite (entre 6 e 10%) (trabalho e projeto elaborado pelos estudantes do curso técnico em agropecuária e da graduação em Medicina Veterinária do IFPB Campus Sousa sob a coordenação e orientação da profa. Me. Esp. Marianne C. Velaqua). 3.4.2 Reflexo da ejeção do leite A sucção do mamilo pelo lactente estimula os receptores sensoriais presentes nesta estrutura, originando a geração de impulsos nervosos que são transmitidos pelas vias nervosas ascendentes da medula espinhal para os corpos celulares produtores de oxitocina no hipotálamo. O estímulo desencadeia a síntese e liberação de um bolo de oxitocina através das terminações nervosas dos núcleos hipotalâmicos para a neurohipófise, da qual é transmitida, através do sangue, para a glândula mamária, provocando a contração das células mioepiteliais que rodeiam os alvéolos (figura 6). Além da estimulação direta do mamilo provocada pela sucção, qualquer estímulo relacionado à ordenha é capaz de gerar o reflexo da ejeção, por exemplo: os estímulos sensoriais auditivos (ruído dos cubos na hora da ordenha), visuais (ambiente da sala de ordenha), táteis (lavagem manual dos mamilos antes da ordenha) e os estímulos olfatórios que se produzem em torno do animal. O desencadeamento do reflexo de ejeção pelos estímulos sensoriais, que não estão diretamente relacionados com a sucção ou ordenha, indica a possível participação de centros superiores do sistema nervoso central para controlar a secreção de oxitocina. Esta teoria é baseada em que os estímulos relacionados com situações de estresse em animais de estimação (medo, ansiedade, frio, etc.) inibem a ejeção do leite. A contração das células mioepiteliais gera um aumento da pressão intra-alveolar mamária, provocando o deslocamento do leite para os ductos maiores da glândula. Este efeito é popularmente conhecido como diminuição do leite e constitui um mecanismo fisiológico muito eficaz para controlar a expulsão do leite para o mamilo, assegurando que a ejeção do leite se realize unicamente quando o lactente o demanda. O efeito estimulante da oxitocina é de grande importância já que a maior parte do leite se encontra nos alvéolos e nos ductos, com o qual, a ausência deste hormônio provocaria um lento movimento do leite para a cisterna do úbere e, portanto, uma menor quantidade de leite. Assim, quando os alvéolos e ductos menores são contraídos, ocorre o relaxamento dos ductos principais, bem como da cisterna (ruminantes) e do mamilo, o que dá origem a um aumento destas estruturas para alojar o volume de leite expelido. Como resultado da volumosa ejeção do leite dos alvéolos e ductos menores, ocorre um aumento da pressão intramamária de modo que o lactente terá que vencer a resistência do esfíncter do mamilo para poder extrair o leite. A produção de leite pela glândula mamária diminui gradualmente à medida que os intervalos de tempo entre os dois períodos de amamentação do lactente diminuem e os estímulos necessários para manter as concentrações de prolactina e oxitocina na circulação sanguínea. A diminuição ou cessação da secreção de leite, geralmente coincide com a mudança na alimentação das crias (desmame) para passar à dieta característica da espécie. 3.5 Colostro O colostro é o primeiro leite que se forma na glândula mamária coincidindo com o parto. A ingestão de colostro por recém-nascidos é de grande importância para a sua sobrevivência, não só pelo seu elevado valor nutritivo, mas também pelo seu teor em imunoglobulinas (IgA) que lhe confere a imunização passiva necessária para o proteger contra patologias. Em algumas espécies (homem, coelho e cobaia) grande parte dos anticorpos passam para a circulação do feto através da placenta durante a gestação. Nos animais domésticos (vaca, égua, ovelha, cabra, porco) as características da placenta (número de camadas entre a circulação materna e fetal) não permitem a passagem destas proteínas. Como resultado, a imunização das crias nestas espécies animais vai depender da transferência das imunoglobulinas através do colostro. O epitélio intestinal dos recém-nascidos permite a passagem destas imunoglobulinas durante as primeiras 24 a 48 horas de vida. Passado este tempo, o epitélio torna-se impermeável à passagem dos anticorpos, fato que põe em evidência a importância que tem para os animais recém-nascidos e desprovidos de defesas a ingestão do colostro durante os primeiros dias. A composição do colostro caracteriza-se (em relação ao leite normal) por um teor mais elevado de proteínas, vitaminas, minerais e uma menor concentração de lactose. A composição do colostro muda gradualmente durante os primeiros três dias após o parto para se transformar em leite normal. 4. RESUMO E PRIMEIRAS CONCLUSÕES O parto, ou processo fisiológico pelo qual se expulsa o feto, é o resultado da maturação sequencial de um sistema de comunicação hormonal. A sequência inicia-se no sistema nervoso central do feto de onde os sinais são transmitidos e amplificados, através da hipófise, para as glândulas adrenais fetais, as quais respondem ao estímulo mediante a secreção de cortisol. O aumento da concentração de cortisol por parte do feto indica que este conseguiu o desenvolvimento necessário para enfrentar a vida extrauterina e, portanto, é hora de interromper a gestação. O cortisol atua sobre a placenta para aumentar a secreção de estrogênios que, por sua vez, estimulam a síntese e a liberação de prostaglandinas. O resultado é a diminuição da progesterona, que é a hormona encarregada de manter a gestação ao inibir as contrações espontâneas do útero, impedindo assim a expulsão prematura do feto. O útero, sob os efeitos da prostaglandina, começa a contrair-se ao mesmo tempo que o colo uterino amolece e dilata progressivamente (fase preparatória do parto). A passagem do feto ao canal do parto origina a secreção reflexa de oxitocina (fase de expulsão), causando contrações de maior frequência e intensidade que culminam com a expulsão do feto. Finalmente, as contrações uterinas continuam durante algum tempo até que finalmente é expulsa a placenta (fase de expulsão da placenta). O desenvolvimento da glândula mamária durante a gestação e a subsequente capacidade desta estrutura para secretar leite, coincidindo com o parto, oferece aos animais pertencentes à classe biológica dos mamíferos a vantagem de alimentar as suas crias para assegurar a sua sobrevivência durante as primeiras fases do seu desenvolvimento e, portanto, a continuidade da espécie. A lactação constitui um dos processos fisiológicos mais complexos em consequência do grande número de hormonas que, segregadas de forma coordenada, controlam as diferentes fases pelo que atravessa este processo: I) mamogênese ou desenvolvimento dos dutos e estruturas lóbulo-alveolares durante a gestação; 2) lactogênese ou síntese láctea por células epiteliais e sua secreção para a luz alveolar coincidindo com o parto, e 3) galactopoiese ou manutenção da síntese e secreção do leite como consequência da sua extração da glândula mamária seja pela sucção da cria ou pela ordenha. -/- Emanuel Isaque Cordeiro da Silva – Departamento de Zootecnia da UFRPE. Recife, 2020. -/- REFERÊNCIAS BIBLIOGRÁFICAS -/- BEIGHLE, D. E. The effect of gestation and lactation on bone calcium, phosphorus and magnesium in dairy cows. Journal of the South African Veterinary Association, v. 70, n. 4, p. 142-146, 1999. BRACKELL, B. G.; JR SEIDEL, G. E.; SEIDEL, S. 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Reproducción en los animales domésticos. Montevidéu: Melibea, 2002. (shrink)

According to a well-known view in the philosophy of mind, intentional attitudes by their very nature satisfy requirements of rationality (e.g. Davidson 1980; Dennett 1987; Millar 2004). This view (which I shall call Constitutivism) features prominently as the ‘principle of minimal rationality’ in de Sousa’s monograph The Rationality of Emotion (1987). By explicating this principle in terms of the notion of the formal object of an attitude, de Sousa articulates an interesting and original version of Constitutivism, which differs in important (...) respects from other extant versions. In this paper, I explore this version of Constitutivism against the background of recent developments in the theory of rationality and make explicit its ramifications for the long-standing dispute over whether the mind is essentially normative. My focus will be on how to conceive of the form of the rationality requirements that attitudes as such must satisfy according to this principle. I argue that, although de Sousa seems officially to endorse a structuralist conception of rationality, according to which these requirements are requirements of coherence, his considerations on formal objects suggest that they are more aptly conceived in terms of a reasons-responsive conception of rationality. I further argue that which of these two readings we choose makes a significant difference to the prospect of vindicating the essential normativity of mind by invoking the principle of minimal rationality. (shrink)

This paper explores the evolution of consciousness and subjectivity through a biological framework for understanding the universe. It posits that functional patterns in biological systems mirror cosmic mathematical principles, defining our objective reality. Similar to wave and Fibonacci patterns in different physical phenomena, biological patterns are intrinsic to all things and can be quantified using Dedre Gentner’s approach to analogy. For example, Earth’s ocean currents and the melting and freezing of Antarctica resemble the circulatory system and heart, while the production (...) of music from instruments is analogous to ribosomal protein synthesis. Shelves, tables, and chairs function like cytosol by holding objects in space, and a coffee cup mirrors red blood cell distribution. These analogies reveal a universal order rooted in biology’s functional patterns, essential for shaping the emergence and evolution of life. The paper traces the development of consciousness from its rudimentary cellular states to complex human cognition, highlighting the role of biologically-patterned environments in driving evolutionary changes. Organisms that recognized and organized according to these patterns evolved as “pattern recognition engines” crucial for survival—thus, Life (survival) being the primary measure of consciousness. Humans advanced this capacity, gaining cognitive freedom by insulating themselves from environmental constraints, but faced increased subjectivity complexity. Consciousness, while inherently subjective and necessary for cognitive development, evolves in humans to understand objective reality and its biological nature, so to understand and navigate complexities of subjectivity. Ultimately, the paper asserts consciousness is the ability to recognize and adhere to life-sustaining patterns and principles. Successful adherence deems them worthy of continued existence, while failure leads to demise. Parallels with historical concepts like Atman and Brahman in Hinduism suggest ancient recognition of the correspondence between human and universal patterns. This ancient understanding, coupled with modern scientific evidence, reveals the interconnectedness and intrinsic biological nature of reality. (shrink)

Elite women seized the public health campaign during the 1900 plague outbreak to assert political influence and advocate for sanitation reform grounded in their domestic experiences. These women advocated for their inclusion in the political sphere by valuing their domestic experiences as knowledge relevant for public health initiatives. This reframing of experience positioned them as viable citizens in the imminent Federation. Applying Laura Zanotti's concept of relational ontology, this analysis frames their actions as not simply a battle against institutional authority (...) but as careful and strategic interactions with their era's political context, exploiting aspects of it that were beneficial to them. Their ambivalent involvement in the public health campaign illustrates a complex chapter in Australian medical history. Women used the opportunity of plague to reevaluate their experience of the home as a form of knowledge relevant to public health. At the same time, they leveraged their growing status as political subjects to oppress others. (shrink)

Over the centuries, magicians have developed extensive knowledge about the manipulation of the human mind—knowledge that has been largely ignored by psychology. It has recently been argued that this knowledge could help improve our understanding of human cognition and consciousness. But how might this be done? And how much could it ultimately contribute to the exploration of the human mind? We propose here a framework outlining how knowledge about magic can be used to help us understand the human mind. Various (...) approaches—both old and new—are surveyed, in terms of four different levels. The first focuses on the methods in magic, using these to suggest new approaches to existing issues in psychology. The second focuses on the effects that magic can produce, such as the sense of wonder induced by seeing an apparently impossible event. Third is the consideration of magic tricks—methods and effects together—as phenomena of scientific interest in their own right. Finally, there is the organization of knowledge about magic into an informative whole, including the possibility of a science centered around the experience of wonder. (shrink)

We show that early vision can use monocular cues to rapidly complete partially-occluded objects. Visual search for easily detected fragments becomes difficult when the completed shape is similar to others in the display; conversely, search for fragments that are difficult to detect becomes easy when the completed shape is distinctive. Results indicate that completion occurs via the occlusion-triggered removal of occlusion edges and linking of associated regions. We fail to find evidence for a visible filling-in of contours or surfaces, but (...) do find evidence for a "functional" filling-in that prevents the constituent fragments from being rapidly accessed. As such, it is only the completed structures—and not the fragments themselves—that serve as the basis for rapid recognition. (shrink)

When looking at a scene, observers feel that they see its entire structure in great detail and can immediately notice any changes in it. However, when brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: identification of changes becomes extremely difficult, even when changes are large and made repeatedly. Identification is much faster when a verbal cue is provided, showing that poor visibility is not the cause of (...) this difficulty. Identification is also faster for objects mentioned in brief verbal descriptions of the scene. These results support the idea that observers never form a complete, detailed representation of their surroundings. In addition, results also indicate that attention is required to perceive change, and that in the absence of localized motion signals it is guided on the basis of high-level interest. (shrink)

This paper explores the extent to which a scientific framework for visualization might be possible. It presents several potential parts of a framework, illustrated by application to the visualization of correlation in scatterplots. The first is an extended-vision thesis, which posits that a viewer and visualization system can be usefully considered as a single system that perceives structure in a dataset, much like "basic" vision perceives structure in the world. This characterization is then used to suggest approaches to evaluation that (...) take advantage of techniques used in vision science. Next, an optimal-reduction thesis is presented, which posits that an optimal visualization enables the given task to be reduced to the most suitable operations in the extended system. A systematic comparison of alternative designs is then proposed, guided by what is known about perceptual mechanisms. It is shown that these elements can be extended in various ways—some even overlapping with parts of vision science. As such, a science of some kind appears possible for at least some parts of visualization. It would remain distinct from design practice, but could nevertheless assist with the design of visualizations that better engage human perception and cognition. (shrink)

Purpose. To determine whether highlights are rapidly identified at early levels of vision. -/- Methods. Visual search experiments were carried out using simple black and white figures corresponding to shiny objects lit from various directions. These included, for example, depictions of cylinders with highlights positioned at various heights (see figure). Targets and distractors differed only in the arrangement of their constituent regions, allowing them to be distinguished by the position of the highlights on the corresponding objects. -/- Results. Three observers (...) were tested. Search is rapid when the target corresponds to a shiny black object with a bottom highlight among objects with top highlights (view figure from rightside up). However, search slows down when the target corresponds to an object with a top highlight among objects with bottom highlights (view figure from upside down). This asymmetry in search speeds is destroyed when the contrast of the figures is reversed. -/- Conclusions. These results indicate that regions in the image can be rapidly identified as highlights at early levels of vision. They also suggest--as for several other rapid recovery processes--that an assumption of lighting from above is used as a simplifying constraint. (shrink)

One of the more powerful impressions created by vision is that of a coherent, richly-detailed world where everything is present simultaneously. Indeed, this impression is so compelling that we tend to ascribe these properties not only to the external world, but to our internal representations as well. But results from several recent experiments argue against this latter ascription. For example, changes in images of real-world scenes often go unnoticed when made during a saccade, flicker, blink, or movie cut. This "change (...) blindness" provides strong evidence against the idea that our brains contain a picture-like representation of the scene that is everywhere detailed and coherent. (shrink)

Recent advances in our understanding of visual perception have shown it to be a far more complex and counterintuitive process than previously believed. Several important consequences follow from this. First, the design of an effective statistical graphics system is unlikely to succeed based on intuition alone; instead, it must rely on a more sophisticated, systematic approach. The basic elements of such an approach are outlined here, along with several design principles. An overview is then given of recent advances in our (...) understanding of visual perception, including rapid perception, visual attention, and scene perception. It then is argued that the mechanisms involved can be successfully harnessed to allow data to be displayed more effectively than at present. Several directions of development are discussed, including effective use of visual attention, the display of dynamic information, and the effective use of nonattentional and nonconscious perceptual systems. (shrink)

This work investigates the ability of the human visual system to discriminate self-similar Gaussian random textures. The power spectra of such textures are similar to themselves when rescaled by some factor h > 1. As such, these textures provide a natural domain for testing the hypothesis that texture perception is based on a set of spatial-frequency channels characterized by filters of similar shape.

Large changes in a scene often become difficult to notice if made during an eye movement, image flicker, movie cut, or other such disturbance. It is argued here that this _change blindness_ can serve as a useful tool to explore various aspects of vision. This argument centers around the proposal that focused attention is needed for the explicit perception of change. Given this, the study of change perception can provide a useful way to determine the nature of visual attention, and (...) to cast new light on the way that it is?and is not?involved in visual perception. To illustrate the power of this approach, this paper surveys its use in exploring three different aspects of vision. The first concerns the general nature of _seeing_. To explain why change blindness can be easily induced in experiments but apparently not in everyday life, it is proposed that perception involves a _virtual representation_, where object representations do not accumulate, but are formed as needed. An architecture containing both attentional and nonattentional streams is proposed as a way to implement this scheme. The second aspect concerns the ability of observers to detect change even when they have no visual experience of it. This _sensing_ is found to take on at least two forms: detection without visual experience (but still with conscious awareness), and detection without any awareness at all. It is proposed that these are both due to the operation of a nonattentional visual stream. The final aspect considered is the nature of visual attention itself?the mechanisms involved when _scrutinizing_ items. Experiments using controlled stimuli show the existence of various limits on visual search for change. It is shown that these limits provide a powerful means to map out the attentional mechanisms involved. (shrink)

A set of visual search experiments tested the proposal that focused attention is needed to detect change. Displays were arrays of rectangles, with the target being the item that continually changed its orientation or contrast polarity. Five aspects of performance were examined: linearity of response, processing time, capacity, selectivity, and memory trace. Detection of change was found to be a self-terminating process requiring a time that increased linearly with the number of items in the display. Capacity for orientation was found (...) to be about 5 items, a value comparable to estimates of attentional capacity. Observers were able to filter out both static and dynamic variations in irrelevant properties. Analysis also indicated a memory for previously-attended locations. These results support the hypothesis that the process needed to detect change is much the same as the attentional process needed to detect complex static patterns. Interestingly, the features of orientation and polarity were found to be handled in somewhat different ways. Taken together, these results not only provide evidence that focused attention is needed to see change, but also show that change detection itself can provide new insights into the nature of attentional processing. (shrink)

Argues that information, in the animal behaviour or evolutionary context, is correlation/covariation. The alternation of red and green traffic lights is information because it is (quite strictly) correlated with the times when it is safe to drive through the intersection; thus driving in accordance with the lights is adaptive (causative of survival). Daylength is usefully, though less strictly, correlated with the optimal time to breed. Information in the sense of covariance implies what is adaptive; if an animal can infer what (...) the information implies, it increases its chances of survival. (shrink)

Five aspects of visual change detection are reviewed. The first concerns the concept of change itself, in particular the ways it differs from the related notions of motion and difference. The second involves the various methodological approaches that have been developed to study change detection; it is shown that under a variety of conditions observers are often unable to see large changes directly in their field of view. Next, it is argued that this “change blindness” indicates that focused attention is (...) needed to detect change, and that this can help map out the nature of visual attention. The fourth aspect concerns how these results affect our understanding of visual perception—for example, the implication that a sparse, dynamic representation underlies much of our visual experience. Finally, a brief discussion is presented concerning the limits to our current understanding of change detection. (shrink)

What is critical thinking, especially in the context of higher education? How have research and scholarship on the matter developed over recent past decades? What is the current state of the art here? How might the potential of critical thinking be enhanced? What kinds of teaching are necessary in order to realize that potential? And just why is this topic important now? These are the key questions motivating this volume. We hesitate to use terms such as “comprehensive” or “complete” or (...) “definitive,” but we believe that, taken in the round, the chapters in this volume together offer a fair insight into the contemporary understandings of higher education worldwide. We also believe that this volume is much needed, and we shall try to justify that claim in this introduction. (shrink)

I critically evaluate the influential new wave account of theory reduction in science developed by Paul Churchland and Clifford Hooker. First, I cast doubt on claims that the new wave account enjoys a number of theoretical virtues over its competitors, such as the ability to represent how false theories are reduced by true theories. Second, I argue that the genuinely novel claim that a corrected theory must be specified entirely by terms from the basic reducing theory is in fact too (...) restrictive for scientific practice and should be rejected. Basic theories co-evolve with nonbasic theories in a mutually interactive way, and thus the basic theories incorporate the concepts and concerns of nonbasic theories. Third, I show that once its ontological consequences are duly noted, the reductive part the new wave account collapses into the classical theory developed within the logical empiricist tradition. As such, it still falls prey to standard anti-reductionist argument based upon multiple realizability and the cross-classification of special science and physical science terms. (shrink)

The present study examined how exposure to the performance of in-group and out-group members can both exacerbate and minimize the negative effects of stereotype threat. Female participants learned that they would be taking a math test that was either diagnostic or nondiagnostic of their math ability. Prior to taking the test, participants interacted with either an in-group peer (a female college student) or an out-group peer (a male college student) who had just taken the test and learned that the student (...) had either performed well or poorly on the test. Exposure to either an in-group or an out-group peer whose performance was consistent with the negative stereotype (a poor-performing female or a strong-performing male) exacerbated stereotype threat effects. In contrast, exposure to an in-group or an out-group peer whose performance challenged the negative stereotype (a strong-performing female or a poor-performing male) eliminated stereotype threat effects. These findings demonstrate that people can look to both in-group and out-group peers as sources of inspiration in the context of a negative stereotype. (shrink)

Functional reduction follows two familiar steps: a definition of a higher-level or special science property in terms of a functional role, then a statement describing a physical property that plays or occupies that role. But Kim (2005) adds a third step, namely, an explanation regarding how the physical property occupies the functional role. I think Kim is correct. But how is the third step satisfied? An examination of the pertinent scientific explanations reveals that the third step is best satisfied by (...) a multiple-subject, part-whole explanation, which is to say, a decomposition of the occupier’s causal capacities or relations. This is true even in cases wherein role and occupant properties are identical, for an occupier’s causal capacities are always underwritten by a part-whole explanation. As a consequence, functional reduction is transformed into a larger picture that at bottom always contains multiple layers of distinct, nonidentical properties that divide between parts and their whole systems. I call it “Part-Based Functional Reduction.” My aim is to develop this larger picture of reduction. (shrink)

This paper explores the ways in which resource limitations influence the nature of perceptual and cognitive processes. A framework is developed that allows early visual processing to be analyzed in terms of these limitations. In this approach, there is no one ``best'' system for any visual process. Rather, a spectrum of systems exists, differing in the particular trade-offs made between performance and resource requirements.

Inner speech is commonly understood as the conscious experience of a voice within the mind. One recurrent theme in the scientific literature is that the phenomenon involves a representation of overt speech, for example, a representation of phonetic properties that result from a copy of speech instructions that were ultimately suppressed. I propose a larger picture that involves some embodied objects and their misperception. I call it “the Body Error Theory,” or BET for short. BET is a form of illusionism, (...) but the particular version I favor is a cross-modal illusion. Newly described here, my hypothesis is that the experience of inner speech arises from a mix of interoception and audition. Specifically, there is the detection of slight but well-confirmed activities in the speech musculature that occur during inner speech, which helps to transform representations of normal but quiet nonverbal sounds that inevitably occur during inner speech, from breathing to background noise, into a mistaken perception of inner speech. Simply put, activities in the speech musculature mix with sounds to create the appearance of speech sounds, which thus explains the “voice within the mind.” I also show how BET’s cross-modal system fits with standard information processing accounts for speech monitoring and how it accommodates the central insights of leading theories of inner speech. In addition, I show how BET is supported by data from experience-sampling surveys and how it can be empirically tested against its rivals. (shrink)

I critically evaluate Bickle’s version of scientific theory reduction. I press three main points. First, a small point, Bickle modifies the new wave account of reduction developed by Paul Churchland and Clifford Hooker by treating theories as set-theoretic structures. But that structuralist gloss seems to lose what was distinctive about the Churchland-Hooker account, namely, that a corrected theory must be specified entirely by terms and concepts drawn from the basic reducing theory. Set-theoretic structures are not terms or concepts but the (...) structures that they describe. Second, and more serious, a familiar problem for classical positivist account of reduction resurfaces within this newest wave of thinking, namely, commitment to property identities and inter-theoretic bridge laws (a problem I discussed at more length in "Collapse of the New Wave"). Indeed, this problem is exacerbated by Bickle’s conciliatory treatment of property plasticity, since he is willing to grant that a large number of special science terms denote multiply realized properties, at least if realistically construed. Still, in the end, Bickle sidesteps the reduction of properties by appealing to Hooker’s "function-to-structure token reduction." This is an interesting move with an intriguing concept of reduction. But problems remain. For, third, Bickle and Hooker's function-to-structure token reduction is actually a guised form of eliminative materialism. But that should be unacceptable since the position extends well beyond any modest revisionism for suspect items from a folk theory, say, in folk psychology or folk biology. Instead, it applies to functional terms and concepts employed throughout well-developed and explanatorily successful sciences. (shrink)

In light of the phenomenon of multiple realizability, many philosophers wanted to preserve the mind-brain identity theory by resorting to a “narrow reductive strategy” whereby one (a) finds mental properties which are (b) sufficiently narrow to avoid the phenomenon of multiple realization, while being (c) explanatorily adequate to the demands of psychological theorizing. That is, one replaces the conception of a mental property as more general feature of cognitive systems with many less general properties, for example, replacing the conception of (...) pain as a general property across different species with a number of species-specific kinds of pain. Many critics focused on (c), arguing that species-specific properties are not explanatorily adequate because they do not capture what is common in pain across species. In this paper I focused on (b). I argued that if one carries the narrow reductive strategy out in such a way to avoid all multiple realizability that occurs within a species, for example, accommodating individual differences by postulating a more narrow pain-relative-to-an-individual-at-a-time, then the result is for all intents and purposes a claim about tokens and not types or properties at all (the position is now about individuals having properties at times, a structured token event). I also added an important point about explanation, viz., that properties-relative-to-individuals-at-times would not serve the explanatory goals of science by failing to generalize to other individuals. (shrink)

Our visual experience of the world is one of diverse objects and events, each with particular colors, shapes, and motions. This experience is so coherent, so immediate, and so effortless that it seems to result from a single system that lets us experience everything in our field of view. But however appealing, this belief is mistaken: there are severe limits on what can be visually experienced. -/- For example, in a display for air-traffic control it is important to track all (...) moving items. For a single item, this can be done without problem. Three or four can also be tracked, although some degree of effort may be needed. As the number is increased further, accurate tracking becomes more and more difficult—and eventually, impossible. Performance is evidently affected by a factor within the observer which enables certain kinds of perception to occur, but is limited in some way. This factor is generally referred to as attention. -/- At various times, attention has been associated with clarity of perception, intensity of perception, consciousness, selection, or the allocation of a limited “resource” enabling various operations (see Hatfield, 1998). During the past several decades, considerable progress has been achieved by focusing on the idea of selection (Broadbent, 1982). In particular, attention can be productively viewed as contingently selective processing. This can be embodied in various ways by various processes—there need not be a single quantity identified with all forms of attention, or a single site where it operates (Allport, 1993; Tsotsos, 2011). Although “paying attention” is often considered to be a unitary operation, it may simply refer to the control of one or more selective processes, ideally in a co-ordinated way. While this view has some cost in terms of conceptual simplicity, it can help make sense of a large set of phenomena. -/- This article surveys several of the major issues in our understanding of attention and how it relates to perception. It focuses on vision, since many—if not all—considerations are similar for all sensory modalities, and the level of understanding achieved in this domain is currently the most advanced. (shrink)

[Ronald de Sousa] Taking literally the concept of emotional truth requires breaking the monopoly on truth of belief-like states. To this end, I look to perceptions for a model of non-propositional states that might be true or false, and to desires for a model of propositional attitudes the norm of which is other than the semantic satisfaction of their propositional object. Those models inspire a conception of generic truth, which can admit of degrees for analogue representations such as emotions; (...) belief-like states, by contrast, are digital representations. I argue that the gravest problem-objectivity-is not insurmountable. /// [Adam Morton ] It is accuracy rather than truth itself that is valuable. Emotional truth is a dubious though attractive notion, but emotional accuracy is much easier to make sense of. My approach to accuracy goes via an account of what makes a story accurate. Stories can be accurate but not true, and emotions can be accurate whether or not they are true. The capacity for emotional accuracy, for emotions that fit a person's situation, is an aspect of emotional intelligence, which is as important an aspect of rational human agency as the intelligent formation of beliefs and desires. (shrink)

Experiments are presented showing that visual search for Mueller-Lyer (ML) stimuli is based on complete configurations, rather than component segments. Segments easily detected in isolation were difficult to detect when embedded in a configuration, indicating preemption by low-level groups. This preemption—which caused stimulus components to become inaccessible to rapid search—was an all-or-nothing effect, and so could serve as a powerful test of grouping. It is shown that these effects are unlikely to be due to blurring by simple spatial filters at (...) early visual levels. It is proposed instead that they are due to more sophisticated processes that rapidly bind contour fragments into spatially-extended assemblies. These results support the view that rapid visual search cannot access the primitives formed at the earliest stages of visual processing; rather, it can access only higher-level, more ecologically-relevant structures. (shrink)

First, I briefly characterize Dretske’s particular naturalization project, emphasizing his naturalistic reconstruction of the notion of representation. Second, I note some apparent similarities between his notion of representation and Husserl’s notion of intentionality, but I find even more important differences. Whereas Husserl takes intentionality to be an intrinsic, phenomenological feature of thought and experience, Dretske advocates an “externalist” account of mental representation. Third, I consider Dretske’s treatment of qualia, because he takes it to show that his representational account of mind (...) succeeds in naturalizing even the “subjective” features of experience. I claim that Dretske's argument for his account of qualia turns on an ambiguous characterization of qualia. I conclude that he succeeds in naturalizing qualia only if qualia are understood as nonphenomenological features of experience and that he therefore has less to say than he thinks about the subjective life of beings such as us. (shrink)

It has often been assumed that when we use vision to become aware of an object or event in our surroundings, this must be accompanied by a corresponding visual experience (i.e., seeing). The studies reported here show that this assumption is incorrect. When observers view a sequence of displays alternating between an image of a scene and the same image changed in some way, they often feel (or sense) the change even though they have no visual experience of it. The (...) subjective difference between sensing and seeing is mirrored in several behavioral differences, suggesting that these are two distinct modes of conscious visual perception. (shrink)

Traditionally, vision science and information/data visualization have interacted by using knowledge of human vision to help design effective displays. It is argued here, however, that this interaction can also go in the opposite direction: the investigation of successful visualizations can lead to the discovery of interesting new issues and phenomena in visual perception. Various studies are reviewed showing how this has been done for two areas of visualization, namely, graphical representations and interaction, which lend themselves to work on visual processing (...) and the control of visual operations, respectively. The results of these studies have provided new insights into aspects of vision such as grouping, attentional selection and the sequencing of visual operations. More generally yet, such results support the view that the perception of visualizations can be a useful domain for exploring the nature of visual cognition, inspiring new kinds of questions as well as casting new light on the limits to which information can be conveyed visually. (shrink)

When brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: the changes become extremely difficult to notice, even when they are large, presented repeatedly, and the observer expects them to occur (Rensink, O'Regan, & Clark, 1997). To determine the mechanisms behind this induced "change blindness", four experiments examine its dependence on initial preview and on the nature of the interruptions used. Results support the proposal that representations at (...) the early stages of visual processing are highly volatile, and that focused attention is needed to stabilize them sufficiently to support the perception of change. (shrink)

This paper explores the evolution of consciousness and subjectivity through a biological framework for understanding the universe. It posits that functional patterns in biological systems mirror cosmic mathematical principles, defining our objective reality. Similar to wave and Fibonacci patterns in different physical phenomena, biological patterns are intrinsic to all things and can be quantified using Dedre Gentner’s approach to analogy. For example, Earth’s ocean currents and the melting and freezing of Antarctica resemble the circulatory system and heart, while the production (...) of music from instruments is analogous to ribosomal protein synthesis. Shelves, tables, and chairs function like cytosol by holding objects in space, and a coffee cup mirrors red blood cell distribution. These analogies reveal a universal order rooted in biology’s functional patterns, essential for shaping the emergence and evolution of life. The paper traces the development of consciousness from its rudimentary cellular states to complex human cognition, highlighting the role of biologically-patterned environments in driving evolutionary changes. Organisms that recognized and organized according to these patterns evolved as “pattern recognition engines” crucial for survival—thus, Life (survival) being the primary measure of consciousness. Humans advanced this capacity, gaining cognitive freedom by insulating themselves from environmental constraints, but faced increased subjectivity complexity. Consciousness, while inherently subjective and necessary for cognitive development, evolves in humans to understand objective reality and its biological nature, so to understand and navigate complexities of subjectivity. Ultimately, the paper asserts consciousness is the ability to recognize and adhere to life-sustaining patterns and principles. Successful adherence deems them worthy of continued existence, while failure leads to demise. Parallels with historical concepts like Atman and Brahman in Hinduism suggest ancient recognition of the correspondence between human and universal patterns. This ancient understanding, coupled with modern scientific evidence, reveals the interconnectedness and intrinsic biological nature of reality. (shrink)

I critically examine some provocative arguments that John Searle presents in his book The Rediscovery of Mind to support the claim that the syntactic states of a classical computational system are "observer relative" or "mind dependent" or otherwise less than fully and objectively real. I begin by explaining how this claim differs from Searle's earlier and more well-known claim that the physical states of a machine, including the syntactic states, are insufficient to determine its semantics. In contrast, his more recent (...) claim concerns the syntax, in particular, whether a machine actually has symbols to underlie its semantics. I then present and respond to a number of arguments that Searle offers to support this claim, including whether machine symbols are observer relative because the assignment of syntax is arbitrary, or linked to universal realizability, or linked to the sub-personal interpretive acts of a homunculus, or linked to a person's consciousness. I conclude that a realist about the computational model need not be troubled by such arguments. Their key premises need further support. (shrink)

Human vision briefly retains a trace of a stimulus after it disappears. This trace—iconic memory—is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report) of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alternating between (...) visible and iconic representations. However, the duration over which it can be used depends on the type of task: some tasks can use iconic memory for at least 240 ms, others for only about 190 ms, while others for no more than about 120 ms. The existence of these different limits suggests that iconic memory may have multiple layers, each corresponding to a particular level of the visual hierarchy. In this view, the inability to use a layer of iconic memory may reflect an inability to maintain feedback connections to the corresponding representation. (shrink)

High-level allocation of attention is required for detecting changes in images under ‘flicker’ conditions, ie when an original and a modified image are repetitively alternated, with a blank field between each display (R A Rensink, J K O'Regan, J J Clark, 1995 Perception24 Supplement, 26). But how many items can attention ‘grab’ and compare during each display? To determine this capacity, search experiments were carried out under flicker conditions, with displays formed of arrays of rectangles. In half the trials, displays (...) differed by the position of one of the rectangles; in the other half, displays remained the same. Subjects were asked to determine if a change was occurring between the two displays. Performance was measured for several durations of displays and blank fields. In all cases, search showed a clear serial deployment of attention. Comparing the rate of this deployment against the rate of display alternation yielded the number of items compared at a time. Results indicate that, for display durations of less than 100 ms, average capacity is about 1.5 items. Capacity increases somewhat with longer display times, indicating that more items can be stored with increasing display time, or that more items are being grouped into each attentional ‘operand’. (shrink)

Objectives: The study determined the competencies of teachers and performance of learners in 2017-2018 National Achievement Test. It identified the influence of teachers’ competencies on performance of learners. Methods: It employed descriptive-correlational and explanatory designs and it involved three divisions in Northern Mindanao region, Philippines. Findings: The Grade 10 and 6 teachers have possessed very satisfactory competencies across areas, while the Grade 10 and Grade 6 learners had a low mastery and very low mastery, respectively. Furthermore, there was no significant (...) relationship between the competencies of teachers and the performance of learners, while their competencies did not significantly influence the performance of learners. Conclusion: Teachers were deemed competent in all areas and learners had not acquired most of the competency standards of the curricula. Hence, no matter how competent teachers are, this would not contribute significantly to improving the performance of learners in the National Achievement Test. Thus, competencies of teachers cannot determine the performance of learners. (shrink)

Let’s begin by imagining a hypothetical psychotic illness called “Schneider’s Disease”, recognized for over 100 years. Let’s assume there has been great controversy as regards the “most valid” set of diagnostic criteria for SD.

Some scientists and philosophers claimed that there is a converse to multiple realizability. While a given higher-level property can be realized by different lower-level properties (multiple realizability), a given lower-level property can in turn serve to realize different higher-level properties (this converse I dubbed the unfortunately obscure "constructival plasticity" to emphasize the constructive metaphysics involved in this converse to multiple realizability). I began by defining multiple realizabilty in a formal way. (Looking back, one point of interest is that I defined (...) modally weak and strong versions of realization, which is relevant to later views about contingent versus necessitarian grounding.) I then turned to the relation in question. By my analysis, for the converse claim to be true, a lower-level property G1 that realizes a higher-level F must be taken in conjunction with some other base condition G2 so that a difference in G2 allows G1 to determine some other higher-level property E but not F (otherwise there would be violations of supervenience). The realization law thus has the form: (G1 & G2) => F. As such, the base property G1 is insufficient by itself to produce F. It is an insufficient but necessary part of a sufficient condition. I also point out that this makes the realization base property an INUS condition, if combined with multiple realizability. Specifically, if F is multiply realized by properties other than the pair G1 and G2, then G1 is an insufficient but necessary part of an unnecessary but sufficient condition. This is just the first clear and explicit INUS condition view of realization in the literature. Looking back, this converse is also relevant to later views, such as Robert Wilson's view about metaphysically contextual realization. (shrink)

I resolve an argument over “flat” versus “dimensioned” theories of realization. The theories concern, in part, whether realized and realizing properties are instantiated by the same individual (the flat theory) or different individuals in a part-whole relationship (the dimensioned theory). Carl Gillett has argued that the two views conflict, and that flat theories should be rejected on grounds that they fail to capture scientific cases involving a dimensioned relation between individuals and their constituent parts. I argue on the contrary that (...) the two types of theory complement one another, even on the same range of scientific cases. I illustrate the point with two popular functionalist versions of flat and dimensioned positions – causal-role functionalism and a functional analysis by decomposition – that combine into a larger picture I call “comprehensive functional realization.” I also respond to some possible objections to this synthesis of functionalist views. (shrink)

This essay explains Donald Hoffman's Interface Theory of Perception using The Biological Framework for a Mathematical Universe proposed by Ronald Williams. According to Hoffman, what we perceive is more like a “desktop interface with icons representing complex underlying processes, rather than a direct window into the true nature of the world." The theory of a biological framework for a mathematical universes suggests that these complex underlying processes of “the desktop interface with icons” contain correspondences to biological systems. For example, (...) “the desktop icons” of the ocean’s arctic currents and the melting and freezing of Antartica contain “complex underlying processes” which mirror the processes of a circulatory system and beating heart. While indeed we do interpret reality from a superficial perspective as Hoffman suggests, our cognitive abilities are enhanced enough to recognize correspondences to these patterns pertaining to these biological systems which reveal the true nature of the world/universe/reality and thus highlight our evolved perceptual systems which can enable us how to recognize these patterns and organize ourselves to them in order to best survive it. Another example of a “desktop icon” is human society—the order and properties of human society contain “complex underlying processes” that are analogous to the order and properties of cellular society—thus “socioeconomic problems” can be understood through cellular economic problems. Moreover, the solution to the cellular economic problem is the solution to the socioeconomic problem. (shrink)

For scatterplots with gaussian distributions of dots, the perception of Pearson correlation r can be described by two simple laws: a linear one for discrimination, and a logarithmic one for perceived magnitude (Rensink & Baldridge, 2010). The underlying perceptual mechanisms, however, remain poorly understood. To cast light on these, four different distributions of datapoints were examined. The first had 100 points with equal variance in both dimensions. Consistent with earlier results, just noticeable difference (JND) was a linear function of the (...) distance away from r = 1, and the magnitude of perceived correlation a logarithmic function of this quantity. In addition, these laws were linked, with the intercept of the JND line being the inverse of the bias in perceived magnitude. Three other conditions were also examined: a dot cloud with 25 points, a horizontal compression of the cloud, and a cloud with a uniform distribution of dots. Performance was found to be similar in all conditions. The generality and form of these laws suggest that what underlies correlation perception is not a geometric structure such as the shape of the dot cloud, but the shape of the probability distribution of the dots, likely inferred via a form of ensemble coding. It is suggested that this reflects the ability of observers to perceive the information entropy in an image, with this quantity used as a proxy for Pearson correlation. (shrink)