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)

Charles Sanders Peirce has commonly been interpreted as a proponent of an epistemic theory of truth. Such a theory has the apparent advantage of directly undercutting radical skepticism, but the disadvantage of implausibly entailing that there are no truths concerning irretrievably lost facts. Recently Andrew Howat has defended Peirce’s epistemic constraint on truth by recasting Peirce’s claim that all truths would be believed following sufficient inquiry, not as constitutive of truth, but as a Wittgensteinian hinge proposition. I begin with a (...) twofold historical reply to Howat: first, Peirce can at least plausibly be read as claiming that the claim in question is analytic of the concept <truth>; and second, while Peirce did think we must accept without evidence the further claim that there are any truths (so characterized), he regarded this further claim not as a Wittgensteinian hinge but as a reasonable hope. I then substantively defend the latter Peircean proposal, arguing that hopes, as against beliefs, are chiefly warranted pragmatically, and so can be warranted even to a sufficient level to render them properly action-guiding in cases where belief in the same proposition would remain unjustified. I conclude by suggesting, first, that this proposal is superior to Wittgenstein’s own epistemology in evading psychologism, and second, that it attractively vindicates the reasonableness of inquiry on Peircean grounds that don’t require an appeal to an implausible epistemic theory of truth. (shrink)

Many have taken Sellars’s critique of empiricism in “Empiricism and the Philosophy of Mind” (EPM) to be aimed at his teacher C. I. Lewis. But if so, why do the famous arguments of its opening sections carry so little force against Lewis’s views? Understandably, some respond by denying that Lewis’s epistemology is among the positions targeted by Sellars. But this is incorrect. Indeed, Sellars had earlier offered more trenchant (if already familiar) critiques of Lewis’s epistemology. What is original about EPM (...) is that it criticizes empiricist positions like Lewis’s not because of their foundationalism, but because of their psychologism about meaning. Since psychologism turns out to be unacceptable by Lewis’s own lights, EPM has a compelling (if implicit) critique of Lewis to offer after all, one that strikes at the heart of his philosophical system. (shrink)

Pragmatist responses to skepticism about empirical justification have mostly been underwhelming, either presupposing implausible theses like relativism or anti-realism, or else showing our basic empirical beliefs to be merely psychologically inevitable rather than rationally warranted. In this paper I defend a better one: a modified version of an argument by Wilfrid Sellars that we are pragmatically warranted in accepting that our perceptual beliefs are likely to be true, since their likely truth is necessary for the satisfaction of our goal of (...) effective agency. On the version of the argument I defend, the great good for human life of control over our empirical circumstances renders our goal of effective agency reasonable. But only if our perceptual beliefs are likely to be true—and only if we accept that this is so, assuming it as a premise for inference and a guide for action—will the success of our actions be due to our effective agency, not mere luck. Since we’re warranted in taking the necessary means to our reasonable ends, we’re warranted in accepting that our perceptual beliefs are generally justified, and so that skepticism about empirical justification is false. (shrink)

While C. I. Lewis was traditionally interpreted as an epistemological foundationalist throughout his major works, virtually every recent treatment of Lewis's epistemology dissents. But the traditional interpretation is correct: Lewis believed that apprehensions of "the given" are certain independently of support from, and constitute the ultimate warrant for, objective empirical beliefs. This interpretation proves surprisingly capable of accommodating apparently contrary textual evidence. The non-foundationalist reading, by contrast, simply cannot explain Lewis's explicit opposition to coherentism and his insistence that only apprehensions (...) of the given enable us to answer the regress problem -- and so vindicate the possibility of empirical justification. (shrink)

In “The Fixation of Belief,” Peirce apparently accepts the causal claim that real physical objects cause us to reach an indefeasible “final opinion” concerning them. In “How to Make Our Ideas Clear,” he apparently accepts the constitutive claim that for physical objects to be real just is for them to be represented in that opinion. These claims initially seem inconsistent, since causal claims are explanatory and since equivalent claims cannot explain one another. Contrary to prominent suggestions that Peirce rejected the (...) constitutive claim, however, he actually accepted both, reconciling them via a Humean denial that causal claims are genuinely explanatory. (shrink)

In this article, I expound and defend an interpretation of Sellars as a metaethical quasi-realist. Sellars analyzes moral discourse in non-cognitivist terms: in particular, he analyzes “ought”-statements as expressions of collective intentions deriving from a collective commitment to provide for the general welfare. But he also endorses a functional-role theory of meaning, on which a statement’s meaning is grounded in its being governed by semantical rules concerning language entry, intra-linguistic, and language departure transitions, and a theory of truth as correct (...) assertibility relative to such semantical rules. On these non-representationalist theories, even though moral statements are expressions of intentions and not fundamentally descriptive, they nevertheless count as assertorically meaningful, and some count as positively true. I further argue that this interpretation is capable not only of explaining Sellars’ explicitly metaethical writings, but also of unifying his scientific realism with his commitment to the ineliminable and indispensable role of the language of intentions: if this linguistic framework does not play an explanatory role, but only an expressive role, this explains both why Sellars’ commitment to it does not contravene his naturalism, as well as why, given the necessity of such language for our practical engagement with the world, the scientific image of humans in the world will only be completed once such language supplements it to enable us to relate practically to it. (shrink)

Since 2023, the UK government's response to the “migrant crisis” has revolved around two controversial flagship policies: the deportation of asylum seekers to Rwanda, and the detention of migrants aboard a giant barge. In this short article, I examine the colonial and gendered dimensions of the two policies, finding them to be examples of the coloniality of gender. What this indicates, I suggest, is that the purpose of these policies is not merely to deter potential migrants—particularly LGBTQIA+ migrants—but also to (...) create a political narrative that allows the Conservative Party to garner right-wing votes by participating in high-profile culture wars; namely, the debate over transgender rights and the debate over how the UK should reckon with its imperial past. (shrink)

I take up two questions raised by Luz Christopher Seiberth's meticulous reconstruction of Wilfrid Sellars's theory of intentionality. The first is whether we should regard Sellars as a transcendental phenomenalist in the most interesting sense of the term: as denying that even an ideally adequate conceptual structure would enable us to represent worldly objects as they are in themselves. I agree with Seiberth that the answer is probably yes, but I suggest that this is due not to Sellars's rejection of (...) the Myth of the Given or appeal to image-models (as Seiberth maintains), but to his view of modality as categorial but as absent from the world an sich. The second is whether, as Richard Rorty complained, Sellars's appeal to picturing lands his theory of intentionality in intractable skepticism. Pace Seiberth, I argue that the transcendental role of picturing does not mitigate this problem, and I suggest that Sellars's most fruitful resource for doing so is not his semantic externalism, but his purely pragmatic response to skepticism. (shrink)

Emotions often misfire. We sometimes fear innocuous things, such as spiders or mice, and we do so even if we firmly believe that they are innocuous. This is true of all of us, and not only of phobics, who can be considered to suffer from extreme manifestations of a common tendency. We also feel too little or even sometimes no fear at all with respect to very fearsome things, and we do so even if we believe that they are fearsome. (...) Indeed, instead of shunning fearsome things, we might be attracted to them. Emotions that seem more thought-involving, such as shame, guilt or jealousy, can also misfire. You can be ashamed of your big ears even though we can agree that there is nothing shameful in having big ears, and even though you judge that having big ears does not warrant shame. And of course, it is also possible to experience too little or even no shame at all with respect to something that is really shameful. Many of these cases involve a conflict between one’s emotion and one’s evaluative judgement. Emotions that are thus conflicting with judgement can be called ‘recalcitrant emotions’. The question I am interested in is whether or not recalcitrant emotions amount to emotional illusions, that is, whether or not these cases are sufficiently similar to perceptual illusions to justify the claim that they fall under the same general heading. The answer to this depends on what emotions are. For instance, the view that emotions are evaluative judgments makes it difficult to make room for the claim that emotional errors are perceptual illusions. Fearing an innocuous spider would simply amount to making the error of judging that the spider is fearsome while it is in fact innocuous. This might involve an illusion of some sort, but it certainly does not amount to anything like a perceptual illusion. In this chapter, I argue that recalcitrant emotions are a kind of perceptual illusion.. (shrink)

Russell is often accused of having a naive ‘Fido’–Fido theory of meaning of the sort Wittgenstein attacked at the beginning of the Philosophical Investigations. In this paper I argue that he never held such a theory though I concede that, prior to 1918, he said various things that might lead a very careless reader to suppose that he had. However, in The Analysis of Mind, a book which we know Wittgenstein studied closely, Russell put forward an account of understanding an (...) utterance which clearly anticipates the use theory of meaning usually attributed to Wittgenstein. The paper concludes with some problems for understanding the use theory of meaning as presented by both Russell and, derivatively, Wittgenstein. (shrink)

This paper explores two related questions in late Athenian and Alexandrian Neoplatonism. First, how can a philosopher contemplate the eternal Forms while engaging in practical agency in the world? Second, do Neoplatonists provide a consistent account of the philosopher’s progress through the ‘stages of virtue’ (βαθμοί τῶν ἀρετῶν), the conceptual structure that underpins late antique philosophical curricula and hagiography? These questions interact, I suggest, because later Platonists appeal to the stages of virtue and divine maniai (βαθμοί τῶν μανίων) to explain (...) the philosopher’s ability to alternate gracefully between contemplation and embodied agency, and even to engage in both activities at the same moment. I argue that apparently contradictory evidence for the highest stages of virtue can be reconciled satisfactorily, shedding light on two models of ethical and perceptual transformation that are consistent throughout later Neoplatonism. In the first, 'painterly' model, we alternate between a vision of the paradigmatic model and its expression in the media of place and time; in the second, 'dancerly' model, we contemplate in action all at once, like a dancer moving to the music. (shrink)

The proliferation of work by autistic writers continues apace, defying a long and multidisciplinary tradition of constructing autistic people as lacking the capacity for narration. To study neurodivergent literature, then, is to witness the refusal of these exclusionary narrative conventions, and to register the ideological presuppositions that underpin pathologization. In this article, I engage with recent insights from Neurodiversity Studies to explore the connections between narrative neuronormativity and other discourses of oppression, especially those that have generated racialized, gendered, and colonial (...) narratives of desubjectification. Focusing on the neuroqueer movement—an emergent practice of disidentification that refuses the interpellations of neuronormativity, ableism, heteronormativity, and cisnormativity—I discuss the concept of allism, arguing that this satirical critique of pathologization harbors a deconstructive force that denaturalizes the dialectic of recognition. Pursuing the discursive context and theoretical implications of this critique, I provide a short genealogy of narrative neuronormativity, connecting the operation of the dialectic in the early novel to the clinical texts of child psychology. To demonstrate the neuroqueer subversion of this tradition, I then read An Unkindness of Ghosts, by Rivers Solomon, a text that stages a disidentification with storytelling. Protagonist Aster’s neuroqueer refusal indexes the concomitance of the construction of Blackness as an ontological foil for whiteness and the construction of autism as a standard of disordered sociality that neuronorms can be measured against. My reading of Unkindness suggests that the extant techniques of literary narratorship are political instruments that will, unless repurposed, continue to disseminate these dispossessive dialectics. (shrink)

Russell’s rejection in 1898 of the doctrine of internal relations — the view that all relations are grounded in the intrinsic properties of the terms related — was a decisive part of his break with Hegelianism and opened the way for his turn to analytic philosophy. Before rejecting it, Russell had given the doctrine little thought, though it played an essential role in the most intractable of the problems facing his attempt to construct a Hegelian dialectic of the sciences. I (...) argue that it was Russell’s early reading of Leibniz, in preparation for his lectures on Leibniz given at Cambridge in 1899, that most probably alerted him to the role the doctrine was playing in his own philosophy. Leibniz defended a similar doctrine and extricated it from difficulties like those faced by Russell by means of devices that were not open to Russell. Russell would have come across these views of Leibniz in writings by Leibniz that he read in the summer of 1898, just before he rejected the doctrine of internal relations. (shrink)

Sellars was an inferentialist about meaning. He thus effectively accorded modality a categorial function, maintaining that any meaningful assertion involves implicit commitment to rules of material inference, which modal propositions explicitly endorse. But Sellars was also a modal anti-realist, construing modality as “entirely immanent to thought” (LRB §40), not present in the world an sich. These two commitments, Klemick argues, render it impossible in principle for us to describe the world an sich adequately, undermining Sellars’ scientific realism, on which, at (...) the “ideal outcome of scientific inquiry,” “the gulf between appearances and things-in-themselves [... can] be bridged” (SM II §51). Sellars’ attempt to ground his modal anti-realism in an ideal “pure description of the world” (CDCM §79) cannot succeed, given modality’s categorial function. Further, his subsequent deployment of picturing as a naturalistic criterion of ontological commitment founders on an analogue of the Kantian problem of noumenal affection: the descriptions of picturing relations that render this proposal intelligible are emptied of content by the denial that the in-itself is modally characterized. Sellars’ worthy aim of preserving the world’s independence of our conceptual activity, Klemick concludes, doesn’t require denying that it exhibits modal relations isomorphic to the semantic relations within our conceptual scheme. (shrink)

In this paper, I develop a metasemantics for relaxed moral realism. More precisely, I argue that relaxed realists should be inferentialists about meaning and explain that the role of evaluative moral vocabulary is to organise and structure language exit transitions, much as the role of theoretical vocabulary is to organise and structure language entry transitions.

Recent debate about the error theory has taken a ‘formal turn’. On the one hand, there are those who argue that the error theory should be rejected because of its difficulties in providing a convincing formal account of the logic and semantics of moral claims. On the other hand, there are those who claim that such formal objections fail, maintaining that arguments against the error theory must be of a substantive rather than a formal kind. In this paper, we argue (...) that formal objections to the error theory cannot be eschewed but must be met head-on. (shrink)

The moral error theory generally does not receive good press in metaethics. This paper adds to the bad news. In contrast to other critics, though, I do not attack error theorists’ characteristic thesis that no moral assertion is ever true. Instead, I develop a new counter-argument which questions error theorists’ ability to defend their claim that moral utterances are meaningful assertions. More precisely: Moral error theorists lack a convincing account of the meaning of deontic moral assertions, or so I will (...) argue. (shrink)

The literature acknowledges a distinction between immoral, amoral and moral management. This paper makes a case for the employee (at any level) as a moral agent, even though the paper begins by highlighting a body of evidence which suggests that individual moral agency is sacrificed at work and is compromised in deference to other pressures. This leads to a discussion about the notion of discretion and an examination of a separate, contrary body of literature which indicates that some individuals in (...) corporations may use their discretion to behave in a socially entrepreneurial manner. My underlying assumption is that CSR isn’t solely driven by economics and that it may also be championed as a result of a personal morality, inspired by employees’ own socially oriented personal values. A conceptual framework is put forward and it is suggested that individuals may be categorized as Active or Frustrated Corporate Social Entrepreneurs; Conformists or Apathetics, distinguished by their individualistic or collectivist personal values. In a discussion of the nature of values, this paper highlights how values may act as drivers of our behavior and pays particular attention to the values of the entrepreneur, thereby linking the existing debate on moral agency with the field of corporate social responsibility. (shrink)

Proclus argues that place (topos) is a body of light, identified as the luminous vehicle of the soul, which mediates between soul and body and facilitates motion. Simplicius (in Phys. 611,10–13) suggests that this theory is original to Proclus, and unique in describing light as a body. This paper focuses on the function of this theory as a bridge between Proclus’ physics and metaphysics, allowing the Aristotelian physical notion of “natural place” to serve as a mechanism for the descent and (...) ascent of the soul. (shrink)

As with all other moral realists, so-called relaxed moral realists believe that there are moral truths. Unlike metaphysical moral realists, they do not take themselves to be defending a substantively metaphysical position when espousing this view, but to be putting forward a moral thesis from within moral discourse. In this paper, I employ minimalism about truth to examine whether or not there is a semantic analysis of the claim ‘There are moral truths’ which can support this moral interpretation of one (...) of moral realism’s key theses. My results are both discouraging and encouraging: Whilst I will argue that the claim ‘There are moral truths’ cannot be shown to be both moral and capable of demarcating relaxed realism from irrealism on the basis of a convincing semantic analysis that would be compatible with relaxed commitments, the moral interpretation of moral realism can be secured by modifying our understanding of what distinguishes relaxed realism from error-theoretic irrealism. Yet, we will see that this moral interpretation of moral realism does not ‘tumble out’ of the semantics provided for its central claims. Rather, hard work needs to be done before we can fully relax. (shrink)

One difficulty in understanding recent debates is that not only have many terms been used to refer to weakness of will – “akrasia” and “incontinence” have often been used as synonyms of “weakness of will” – but quite different phenomena have been discussed in the literature. This is why the present entry starts with taxonomic considerations. The second section turns to the question of whether it is possible to freely and intentionally act against one’s better judgment.

This paper argues for a conception of the natural rights of non-human animals grounded in Kant’s explanation of the foundation of human rights. The rights in question are rights that are in the first instance held against humanity collectively speaking—against our species conceived as an organized body capable of collective action. The argument proceeds by first developing a similar case for the right of every human individual who is in need of aid to get it, and then showing why the (...) situation of animals is similar. I first review some of the reasons why people are resistant to the idea that animals might have rights. I then explain Kant’s conception of natural rights. I challenge the idea that duties of aid and duties of kindness to animals fit the traditional category of “imperfect duties” and argue that they are instead cases of “imperfect right.” I explain how you can hold a right against a group, and why it is legitimate to conceive of humanity as such a group. I then argue that Kant’s account of the foundation of property rights is grounded in a conception of the common possession of the Earth that grounds a right to aid and the rights of animals to be treated in ways that are consistent with their good. Finally, I return to the objections to the idea that animals have rights and offer some responses to them. (shrink)

According to recent suggestions within the global pragmatism discussion, metaethical debate must be fundamentally re-framed. Instead of carving out metaethical differences in representational terms, it has been argued that metaethics should be given an inferentialist footing. In this paper, I put inferentialist metaethics to the test by subjecting it to the following two criteria for success: Inferentialist metaethicists must be able to save the metaethical differences between moral realism and expressivism, and do so in a way that employs understandings of (...) these metaethical accounts which would be acceptable to moral realists or expressivists who endorse an inferentialist theory of meaning. Two results follow from my discussion. The first concerns inferentialist metaethics more narrowly, casting doubts on inferentialists’ ability to fulfil the two criteria for success by showing that proposed metaethical demarcation attempts either meet the first criterion but violate the second, or pass the second criterion but fail the first. The second upshot pertains to the global pragmatism debate more widely, pressing the point that inferentialists have not as yet provided a convincing account of ontological commitment. (shrink)

In this paper, we consider the question of whether there exists an essential relation between emotions and wellbeing. We distinguish three ways in which emotions and wellbeing might be essentially related: constitutive, causal, and epistemic. We argue that, while there is some room for holding that emotions are constitutive ingredients of an individual’s wellbeing, all the attempts to characterise the causal and epistemic relations in an essentialist way are vulnerable to some important objections. We conclude that the causal and epistemic (...) relation between emotions and wellbeing is much less strong than is commonly thought. (shrink)

The focus of this article is the "good-will theory", which explains the effect humans can have on the safety of AI, along with how it is in the best interest of a superintelligent AI to work alongside humans and not overpower them. Future papers dealing with the good-will theory will be published, but discuss different talking points in regards to possible or real objections to the theory.

Evaluative concepts and emotions appear closely connected. According to a prominent account, this relation can be expressed by propositions of the form ‘something is admirable if and only if feeling admiration is appropriate in response to it’. The first section discusses various interpretations of such ‘Value-Emotion Equivalences’, for example the Fitting Attitude Analysis, and it offers a plausible way to read them. The main virtue of the proposed way to read them is that it is well-supported by a promising account (...) of emotions, namely the Perceptual Theory of Emotions, which emphasises the analogies between emotions and sensory perceptual experiences. The second section considers a worry about whether concepts such as admirable are really evaluative. It is maintained that even though the arguments used to show that thick terms and concepts are not inherently evaluative can be transposed to affective concepts, these arguments can be resisted. So there is no need to abandon the intuitive claim that affective concepts are inherently evaluative. (shrink)

After discussing de Sousa's view of emotion in akrasia, I suggest that emotions be viewed as nonconceptual perceptions of value (see Tappolet 2000). It follows that they can render intelligible actions which are contrary to one's better judgment. An emotion can make one's action intelligible even when that action is opposed by one's all-things-considered judgment. Moreover, an akratic action prompted by an emotion may be more rational than following one's better judgement, for it may be the judgement and not the (...) perception which is in error. By contrast, "cool" akrasia is genuinely puzzling; it is not clear whether it exists. (shrink)

Ascribing moral responsibility in collective action cases is notoriously difficult. After all, if my individual actions make no difference with regard to the prevention of climate change, the alleviation of poverty, or the outcome of national elections, why ought I to stop driving, donate money, or cast my vote? Neither consequentialist nor non-consequentialist moral theories have straightforward responses ready at hand. In this contribution, I present a new suggestion which, based on thoughts about causal overdetermination along the lines of Mackie’s (...) INUS account, aims to show that causally overdetermined collective action cases are morally arbitrary in a way that makes it possible to ascribe moral responsibility even if individual actions make no difference. (shrink)

This paper provides suggestions for educators who have a desire to learn about, or are already committed to, challenging ableism and disablism. As philosophy teachers, we have the opportunity to facilitate student reflection regarding disability, which puts students in a position to make decisions about whether to retain their habitual ways of comporting themselves toward disabled people or to begin the process of forming new perceptual practices. I contend that existential phenomenology, as formulated by Maurice Merleau-Ponty and Linda Martín Alcoff, (...) provides insights regarding the habitual formation of perceptual practices that are useful for thinking about ways that perception may be informed by ableism and disablism. Jessica Cadwallader demonstrates how their insights can be usefully applied to thinking about perceptions of disability. Through analysis of past encounters with people with disabilities, Cadwallader suggests that students change their habitual ways of responding to people with disabilities. While such reflections may be valuable for making habitual perceptual practices explicit, I would suggest that this is only a condition for the possibility of changing ablist perceptual practices rather than the change itself. Students are likely to enter the classroom lacking the insight that they are even engaging in perceptual practices informed by cultural narratives rather than simply perceiving people with impairments as they are. I argue that an approach to teaching on disability that thematizes perceptual practices regarding disability, and takes experiences of disabled people into account, would be more effective than the one Cadwallader describes. Understanding the ways that people with disabilities experience being constructed as a problem through ableist perceptual practices could help students recognize their own potential to impact others in positive and negative ways. (shrink)

It is generally accepted that there are two kinds of normative concepts : evaluative concepts, such as good, and deontic concepts, such as ought. The question that is raised by this distinction is how it is possible to claim that evaluative concepts are normative. Given that deontic concepts appear to be at the heart of normativity, the bigger the gap between evaluative and deontic concepts, the less it appears plausible to say that evaluative concepts are normative. After having presented the (...) main differences between evaluative and deontic concepts, and shown that there is more than a superficial difference between the two kinds, the paper turns to the question of the normativity of evaluative concepts. It will become clear that, even if these concepts have different functions, there are a great many ties between evaluative concepts, on the one hand, and the concepts of ought and of reason, on the other. (shrink)

Most of those who hold that emotions involve appraisals also accept that the content of emotions is nonconceptual. The main motivation for nonconceptulism regarding emotions is that it accounts for the difference between emotions and evaluative judgements. This paper argues that if one assumes a broadly Fregean account of concepts, there are good reasons to accept that emotions have nonconceptual contents. All the main arguments for nonconceptualism regarding sensory perception easily transpose to the case of emotions. The paper ends by (...) responding to two important objections: firstly, that nonconceptualism rules out the possibility that emotions justify evaluative judgements and secondly, that nonconceptualism cannot account for the fact that some emotions have conceptually articulated cognitive bases. (shrink)

Much thought has been devoted to how metaethical disagreement between moral realism and expressivism can be saved once minimalism starts creeping. Very little thought has been given to how creeping minimalism affects error-theories’ disagreement with their metaethical competitors. The reason for this omission, I suspect, is found in the belief that whilst locating distinctive moral realist and expressivist positions within a minimalist landscape poses a severe challenge, no such difficulties are encountered when differentiating error-theories from moral realism and expressivism. In (...) the first part of this paper, I show that this belief is mistaken: Insofar as moral realists and error-theorists are still taken to disagree, creeping minimalism renders their disagreement moral, but makes these positions metaethically indistinguishable. In the second part of the paper, I present a modified inferentialist solution to the problem of creeping minimalism which seeks to put error-theories back on the metaethical map. Yet, this too comes at a cost, in that it significantly modifies our interpretation of error-theories. Whichever way we turn, then, creeping minimalism not only forces us to re-phrase metaethical positions in a way that is compatible with minimalism, but also requires us to change our very understanding of these positions. (shrink)

The punishment of social misconduct is a powerful mechanism for stabilizing high levels of cooperation among unrelated individuals. It is regularly assumed that humans have a universal disposition to punish social norm violators, which is sometimes labelled “universal structure of human morality” or “pure aversion to social betrayal”. Here we present evidence that, contrary to this hypothesis, the propensity to punish a moral norm violator varies among participants with different career trajectories. In anonymous real-life conditions, future teachers punished a talented (...) but immoral young violinist: they voted against her in an important music competition when they had been informed of her previous blatant misconduct toward fellow violin students. In contrast, future police officers and high school students did not punish. This variation among socio-professional categories indicates that the punishment of norm violators is not entirely explained by an aversion to social betrayal. We suggest that context specificity plays an important role in normative behaviour; people seem inclined to enforce social norms only in situations that are familiar, relevant for their social category, and possibly strategically advantageous. (shrink)

Metaethics is traditionally understood as a non-moral discipline that examines moral judgements from a standpoint outside of ethics. This orthodox understanding has recently come under pressure from anti-Archimedeans, such as Ronald Dworkin and Matthew Kramer, who proclaim that rather than assessing morality from an external perspective, metaethical theses are themselves substantive moral claims. In this paper, I scrutinise this anti-Archimedean challenge as applied to the metaethical position of expressivism. More precisely, I examine the claim that expressivists do not avoid moral (...) commitments when accounting for moral thought, but instead presuppose them; they do not look at ethics from the outside, but operate from within ethics. This paper defends the non-moral status of expressivism against anti-Archimedeanism by rejecting a new anti-Archimedean challenge which, on the basis of Hume’s Law, aims to exploit expressivist explanations of supervenience in order to show that expressivism is a substantive moral position. (shrink)

Access to surrogacy is often cast in the language of rights. Here, I examine what form such a right could take. I distinguish between surrogacy as a right to assisted procreation, and surrogacy as a contractual right. I find the first interpretation implausible: it would give rise to claims against the state that no state can fulfil, namely the provision of sufficient surrogates to satisfy the need. Instead, I argue that the right to surrogacy can only be plausibly understood as (...) a contractual right. I then investigate two different sets of harms that are often employed to argue against such a contractual interpretation of the right to surrogacy: harm to women's interests in a gendered society, and harm to the sense of self of the surrogate. I assess both of these through the analytical lens of vulnerability. I find neither of them to be convincing arguments against surrogacy contracts. In conclusion, I agree that surrogacy contracts should be carefully regulated, but I disagree with those who call for prohibition of the right to surrogacy as a contractual right. (shrink)

This article revisits, analyzes and critiques Bruce Chatwin’s 1987 bestseller, The Songlines,1 more than three decades after its publication. In Songlines, the book primarily responsible for his posthumous celebrity, Chatwin set out to explore the essence of Central and Western Desert Aboriginal Australians’ philosophical beliefs. For many readers globally, Songlines is regarded as a—if not the—definitive entry into the epistemological basis, religion, cosmology and lifeways of classical Western and Central Desert Aboriginal people. It is argued that Chatwin’s fuzzy, ill-defined use (...) of the word-concept “songlines”2 has had the effect of generating more heat than light. Chatwin’s failure to recognize the economic imperative underpinning Australian desert people’s walking praxis is problematic: his own treks through foreign lands were underpropped by socioeconomic privilege. Chatwin’s ethnocentric idée fixe regarding the primacy of “walking” and “nomadism,” central to his Songlines thématique, well and truly preceded his visits to Central Australia. Walking, proclaimed Chatwin, is an elemental part of “Man’s” innate nature. It is argued that this unwavering, preconceived, essentialist belief was a self-serving construal justifying Chatwin’s own “nomadic” adventures of identity. Is it thus reasonable to regard Chatwin as a “rogue author,” an unreliable narrator? And if so, does this matter? Of greatest concern is the book’s continuing majority acceptance as a measured, accurate account of Aboriginal belief systems. With respect to Aboriginal desert people and the barely disguised individuals depicted in Songlines, is Chatwin’s book a “rogue text,” constituting an act of epistemic violence, consistent with Spivak’s usage of that term? (shrink)

Despite the widespread use of the notion of moral intuition, its psychological features remain a matter of debate and it is unclear why the capacity to experience moral intuitions evolved in humans. We first survey standard accounts of moral intuition, pointing out their interesting and problematic aspects. Drawing lessons from this analysis, we propose a novel account of moral intuitions which captures their phenomenological, mechanistic, and evolutionary features. Moral intuitions are composed of two elements: an evaluative mental state and a (...) feeling of rightness (FOR). We illustrate the phenomenology of the FOR with examples of non-moral and moral cases, and provide a biological and mechanistic account: the emergence of human reasoning capacities created a need for the co-evolution of a psychological system producing the feeling of rightness (the FORs). This system is triggered when we experience conflicting evaluations. The FORs renders evaluations resulting from rational deliberation less compelling than the evaluations produced by simple evolved systems. It thus facilitates optimal decision-making, preventing excessive interference by rational deliberation. Our account sheds light on why moral intuitions are so frequently experienced and why they are so compelling and resistant to argument. In addition, the account fuels interesting speculations about common metaethical intuitions. (shrink)

In the context of feminist and postmodern thought, traditional conceptions of masculinity and what it means to be a “Real Man” have been critiqued. In Genevieve Lloyd's The Man of Reason, this critique takes the form of exposing the effect that the distinctive masculinity of the “man of reason” has had on the history of philosophy. One major feature of the masculine-feminine dichotomy will emerge as a key notion for understanding the rest of the paper: the dichotomy of reason-feeling, a (...) parallel and a foundational aspect to the dichotomy of masculinity and femininity. In exploring the history of symbolic conceptions of masculinity in ancient Greece, the Renaissance, and the present, one finds that the oppression of women is integrally linked to the traditional tie between masculinity and reason. There have been many efforts in recent feminist philosophy to rewrite or redefine “Woman” in such a way as to alleviate the oppression of women. I argue that the effectiveness of rewriting Woman for this purpose is problematic, primarily because any rewriting of this type must occur in the current historical context of hierarchical dualisms, like Man-Woman, masculine-feminine, male-female. These binary oppositions arguably find their roots in Pythagorean philosophy and can be traced through the Renaissance to our current historical context. It is these dualisms that have traditionally valued the masculine side of the Man-Woman dichotomy more than the feminine. Further, it will be argued that the hierarchical dualism of Man and Woman is so pervasive that if we rewrite or redefine the inferior, deprivileged side of that dualism, we cannot correct its devalued status. Instead, we redefine that which is undervalued but retain its devalued status. This particular aspect of attempts to critique hierarchical dualisms like reason and feeling has been reflected in the writings of many feminists, male and female. This paper will show that in cases where women attempt to redefine the dichotomy by revaluing the traditionally feminine (like feelings and emotions) over the traditionally masculine (like reason) their work is often mistakenly criticized for being purely political; conversely, when men attempt to redefine the same dichotomy in an attempt to allow men to “get back in touch with their feelings,” to be nurturers, their work is described in terms of providing a better epistemology. The current literature on masculinity explores alternatives to rewriting or redefining Woman that try to avoid the problem of status remaining with redefinition. This alternative is rewriting or redefining Man. Through redefining Man, one may be able to reconceptualize the privileged side of the hierarchical dualism in such a way that it is no longer privileged. Deprivileging, as well as redefining Man, is argued by theorists of masculinity to be possible because while the devalued status of the inferior side of a hierarchical dualism tends to keep the same status when redefined, it may be possible to redefine the privileged side of the dualism in such a way that it loses its privileged status. Unfortunately, many of these attempts to rewrite or redefine masculinity have detrimental faults of their own. Finally, this paper will discuss more promising possibilities for new definitions of Man, as well as a vision for better interaction between the work of women and men in general. (shrink)

This contribution considers whether or not it is possible to devise a coherent form of external skepticism about the normative if we ‘relax’ about normative ontology by regarding claims about the existence of normative truths and properties themselves as normative. I answer this question in the positive: A coherent form of non-normative error-theories can be developed even against a relaxed background. However, this form no longer makes any reference to the alleged falsity of normative judgments, nor the non-existence of normative (...) properties. Instead, it concerns a specifically inferentialist construal of error-theories which suggests that error-theorists should abstain from any claims about normative ontology to focus exclusively on claims about the inferential role of normative vocabulary. As I will show, this suggestion affords a number of important advantages. However, it also comes at a cost, in that it might not only change the letter, but also the spirit of traditional error-theories. (shrink)

Numerous agricultural wastes are impractically discarded every day, and one of these is rice bran. This study investigated the production of a biodegradable straw made of cassava starch and powdered rice bran. It aimed to determine the effectiveness of the different treatments of Cassava Starch-Rice Bran in terms of water resistance, tensile strength, and biodegradability. An experimental design was used in conducting the study. There were three treatments made in making CSRB straws: the first, with more rice bran; the second, (...) with the same cassava starch and rice bran ratio; and the third, with more cassava starch. These treatments produced three replicates each. The straws were placed in a dehydrating machine for 24 hours at a temperature of 60° Celsius. The straws were then coated with beeswax after being removed from their respective molders. The CSRB straws were found to be water resistant due to the beeswax coating applied, although it had a weak tensile strength even with the presence of beeswax. The rate of biodegradability of the CSRB straw was fast due to it being made up of organic materials. The results revealed that straws made from Cassava Starch and Powdered Rice Bran are effective in terms of water resistance and biodegradability. (shrink)

Are values objective or subjective? To clarify this question we start with an overview of the main concepts and debates in the philosophy of values. We then discuss the arguments for and against value realism, the thesis that there are objective evaluative facts. By contrast with value anti-realism, which is generally associated with sentimentalism, according to which evaluative judgements are grounded in sentiments, value realism is commonly coupled with rationalism. Against this common view, we argue that value realism can be (...) combined with sentimentalism, and we suggest that a plausible account, which we call ‘sentimental realism’, and according to which evaluative judgements are closely related to emotions, can be developped. (shrink)

Globally, languages are disappearing at an unprecedented rate. To establish successful strategic options on how to protect the language's survival, members of linguistic communities must be knowledgeable of the reasons for language extinction or endangerment. This paper discusses how the number of people who speak Pangasinan, which is the eighth most common language in the Philippines, is decreasing over time and how this is affecting the language. It gives an outline of the Pangasinan language's current vitality and covers the Philippines' (...) language policy history. It also considers a situation in which globalization may provide unexpected chances for language revitalization. This study seeks to serve as a springboard for future research and aids teachers and other relevant educational personnel in identifying, comprehending, assessing, and implementing appropriate language-endangerment remedies. The authors also provide suggestions for future research based on their findings. (shrink)

A wide variety of sources, including the Huntington literature and popular mass media, show that Huntington’s “clash of civilizations” idea actually has very little value in understanding the current global political context. The central assumption of Huntington’s view, that cultural kinship ties influence loyalties and agreements on a global scale, has little to do with the daily lives of American citizens and little to do with the decisions made by the current presidential administration. The mass media evidence from the United (...) States shows that the most important “kinship” ties are not religious or cultural, but economic. The argument involves a deeper analysis of the current trend towards religious programs on American television, a timeline of events relating to the Halliburton – Cheney relationship, and views expressed by members of the United States military in Stars and Stripes. (shrink)

Empirical assessments of Cognitive Behavioral Theory and theoretical considerations raise questions about the fundamental theoretical tenet that psychological disturbances are mediated by consciously accessible cognitive structures. This paper considers this situation in light of emotion theory in philosophy. We argue that the “perceptual theory” of emotions, which underlines the parallels between emotions and sensory perceptions, suggests a conception of cognitive mediation that can accommodate the observed empirical anomalies and one that is consistent with the dual-processing models dominant in cognitive psychology.

This chapter provides an introductory overview of quasi-realism and its key challenges.

Within the social sciences, much controversy exists about which status should be ascribed to the rationality assumption that forms the core of rational choice theories. Whilst realists argue that the rationality assumption is an empirical claim which describes real processes that cause individual action, instrumentalists maintain that it amounts to nothing more than an analytically set axiom or ‘as if’ hypothesis which helps in the generation of accurate predictions. In this paper, I argue that this realist-instrumentalist debate about rational choice (...) theory can be overcome once it is realised that the rationality assumption is neither an empirical description nor an ‘as if’ hypothesis, but a normative claim. (shrink)

The history of sonar technology provides a fascinating case study for philosophers of science. During the first and second World Wars, sonar technology was primarily associated with activity on the part of the sonar technicians and researchers. Usually this activity is concerned with creation of sound waves under water, as in the classic “ping and echo”. The last fifteen years have seen a shift toward passive, ambient noise “acoustic daylight imaging” sonar. Along with this shift a new relationship has begun (...) between sonar technicians and environmental ethics. I have found a significant shift in the values, and the environmental ethics, of the underwater community by looking closely at the term “noise” as it has been conceptualized and reconceptualized in the history of sonar technology. To illustrate my view, I will include three specific sets of information: 1) a discussion of the 2003 debate regarding underwater active low- frequency sonar and its impact on marine life; 2) a review of the history of sonar technology in diagrams, abstracts, and artifacts; 3) the latest news from February 2004 on how the military and the acoustic daylight imaging passive sonar community has responded to the current debates. (shrink)

Over the last three years I have been fortunate to teach an unusual class, one that provides an academic background in ethical and social and political theory using the medium of comedy. I have taught the class at two schools, a private liberal arts college in western Pennsylvania and a public regional state university in southern Georgia. While the schools vary widely in a number of ways, there are characteristics that the students share: the school in Pennsylvania had a large (...) population of students raised in a middle class industrial context, and the school in Georgia had a majority of students from middle-to-lower class agricultural backgrounds. Because of recent collapses in the economy of the tool and dye industry in the Great Lakes region, and the ongoing concerns for development in rural and urban areas of the southeastern United States, both groups of students were in similarly dire economic and working conditions. All faced the distinct possibility that they would not do as well in life as their parents. Most of the students grew up with television and film and had a love of comedy when they arrived at college. -/- Entertainment and mass media contributed to the students' mindset and the lens through which they viewed and interpreted their lived experience. Comedic mass media in the form of television sitcoms and films were common choices for inexpensive entertainment, in their childhood, in their past, in their homes, and now in their college dorms and apartments. In asking students to connect their own history with cultural trends depicted in comedy in film and television, even through the history of television, gave the students a familiar venue to critically consider their own intellectual growth and development and that of American society as a whole. -/- Many of them were familiar with the internet, and enjoyed the internet as a source of information about celebrities as well as the history and episodes of their favorite television shows and films. Students are rediscovering and discovering television programs that their professors may have watched as children, with the availability of a wide range of comedy television programs available on cable, especially TVLand, Comedy Central and Nick-at-Night. -/- In this article I will elaborate on the value of comedy as a teaching tool for philosophers and professors. I will provide a number of examples, showing how comedy can provide fertile examples of ethical theory at work, and I will show how comedy can be used to clarify cultural norms and values. Finally, I will discuss the political activism and student empowerment involved in teaching Philosophy, Comedy and Film in southern Georgia. (shrink)