A short summary of Carnap’s Logical Syntax of Language.

TRANSPORTE DE GAMETAS, FERTILIZAÇÃO E SEGMENTAÇÃO -/- • _____OBJETIVO -/- O entendimento do desenvolvimento embrionário nos estágios iniciais, desde a deposição dos espermatozoides na fêmea, passando pela fertilização deste no ovócito e na formação do zigoto, é de suma importância para diferenciar especialistas em reprodução e manejo reprodutivo no mercado de trabalho e, também, durante a vida acadêmica. Compreender os processos que levam à formação do zigoto na fêmea é essencial para avaliar a capacidade reprodutiva dos animais e, mediante técnicas, (...) avaliar o trato reprodutivo da fêmea e o desenvolvimento do embrião até a formação do feto e, por fim, em um novo animal sadio na propriedade. Com esse trabalho, o estudante de veterinária ou zootecnia, que deseja se aprofundar na fisiologia da reprodução animal, identificará os mecanismos que são envolvidos no transporte dos gametas, bem como os processos que estes últimos devem completar para alcançar a fertilização e para desencadear as divisões iniciais do embrião. -/- • _____INTRODUÇÃO -/- A fertilização ou fecundação é o processo pelo qual os gametas masculino (espermatozoide) e feminino (ovócito) se fundem para gerar um novo indivíduo. Seu êxito depende da culminação adequada dos diferentes processos que devem sofrer os gametas durante sua maduração e percurso; do transporte oportuno destes no trato reprodutivo da fêmea, assim como de uma série de adaptações dos órgãos genitais internos da mãe. A segmentação refere-se às primeiras divisões celulares do embrião. -/- • _____TRANSPORTE DO OVÓCITO -/- O ovócito que é liberado na ovulação, e que se encontra coberto pelas células do cumulus (figura 1), é capturado pela fímbria do infundíbulo ao aderir aos cílios. Esse processo é altamente eficaz, inclusive em espécies onde os ovários possuem várias formações globosas, por exemplo nas porcas, onde os ovidutos capturam entre 95 e 100% dos ovócitos que são ovulados. As contrações das camadas musculares do oviduto e o movimento intenso dos cílios da mucosa faz com que as secreções fluam em direção ao útero, transportando assim o complexo cumulus-ovócito. Esse transporte é relativamente rápido até alcançar a junção da ampola com o istmo (que é considerado o local de fertilização do espermatozoide e ovócito) a partir do qual se torna lento. Devido a fêmea estar em estro, o processo está sob controle endócrino, isto é, controle hormonal através do estradiol. Nas fêmeas domésticas, ao contrário das mulheres, o transporte ao longo do oviduto é extremamente eficiente, pois os embriões passam para o útero sem dificuldade, de modo que gestações ectópicas (tubárias ou em cavidade) são quase inexistentes. A égua, frequentemente, retém por muito tempo os ovócitos não fertilizados no oviduto, provavelmente devido a não secreção de substâncias (como a prostaglandina E) que poderiam favorecer sua passagem, como se propõe que aconteça com os embriões. A figura 2 apresenta um ovócito com suas respectivas estruturas. Figura 1: ovócitos de uma vaca madurados in vitro. Nota-se as células do cumulus que os recobre. -/- Figura 2: estruturas do ovócito de uma ovelha que se encontra na etapa de ovócito secundário, depois da ovulação. Elaborado pelo autor. • _____TRANSPORTE ESPERMÁTICO -/- Para que os espermatozoides sejam capazes de fertilizar o ovócito, deverão sofrer uma série de mudanças bioquímicas e morfológicas ao longo de sua passagem pelo aparelho reprodutor tanto masculino como feminino. Uma vez produzidos na parede do túbulo seminífero, os espermatozoides são liberados em direção ao lúmen tubular e transportados passivamente para uma estrutura ramificada conhecida como rede testicular (rete testis). Dessa rede são conduzidos em direção ao epidídimo passando através de 10 a 20 ductos eferentes localizados no polo superior do testículo. O epidídimo é dividido em três seções denominadas cabeça, corpo e cauda; é constituído por um só ducto longo e tortuoso que continua com o canal deferente. Ao final desemboca nas ampolas seminais, no ducto ejaculatório e na uretra. As funções do epidídimo são as de maduração, transporte e armazenamento dos espermatozoides. O transporte através do epidídimo é lento, aproximadamente de 10 dias em touros, e segue sendo passivo. Os espermatozoides tomados da cabeça do epidídimo são ainda imaturos e incapazes de fertilizar, enquanto os armazenados na cauda são completamente maduros. Durante o trânsito pelo epidídimo os espermatozoides adquirem motilidade e o potencial para fertilizar, o acrossomo é remodelado e a gota citoplasmática migra para o flagelo e é liberada. Quando um macho ejacula com muita frequência, é possível observar espermatozoides com gota citoplasmática no sêmen, já que não há tempo suficiente para que completem sua maduração. Os espermatozoides são expulsados fora do organismo durante a cópula, na masturbação ou em emissões espontâneas. Na ejaculação, os espermatozoides que se encontram suspensos nos fluidos do testículo e do epidídimo, misturam-se ao chegar na uretra com as secreções das glândulas acessórias para formar o sêmen. Essas secreções denominadas plasma seminal, proporcionam substâncias para manter o metabolismo energético das células espermáticas, e integram suas membranas elementos que impedem uma capacitação prematura. Durante a cópula, o sêmen é depositado na vagina ou no útero, variando entre as espécies (tabela 1). Na monta natural, geralmente, o serviço ocorre no momento propício, já que está definido pela fase do ciclo estral em que a fêmea é receptiva ao macho. No entanto, na inseminação artificial, é o macho que deverá determinar o momento ideal, e para isso é importante considerar a vida média dos gametas, ao qual é muito curta no caso dos ovócitos (tabela 1). -/- Tabela 1: local de depósito do sêmen, volume da ejaculação e vida média dos gametas. Espécie Local de deposição Volume (ml) Velocidade de ejaculação Vida média do ovócito Vida média do espermatozoide Bovinos Intravaginal 2 1 – 3 seg 8 h 30 – 48 h Caninos Intravaginal 2 – 30 (10 média) 6 – 45 min 48 – 72 h 9 – 11 d Equinos Intrauterina 50 – 200 20 – 60 seg 6 – 8 h 72 – 120 h Humanos Intravaginal 3 - - 5 – 6 d Ovinos Intravaginal 1 1 – 2 seg 16 – 24 h 30 – 48 h Suínos Intrauterina 200 – 400 5 – 20 min 8 – 10 h 24 – 48 h Onde d = dias; h = horas. A vida fértil do ovócito é muito curta, portanto, o momento do serviço é de grande importância para obter altos índices de fertilização. -/- Independentemente do local em que os espermatozoides sejam depositados no aparelho reprodutor feminino, serão expostos às secreções genitais e sofrem uma série de mudanças em seu trajeto até o local de fertilização antes de penetrar no ovócito. Nas espécies em que o sêmen é depositado na parte cranial da vagina, uma parte do mesmo penetra através da cérvix, enquanto outra parte é eliminada do aparelho genital da fêmea, em pouco tempo, através do fluxo retrógrado. O meio vaginal não é adequado e imobiliza os espermatozoides em pouco tempo, pelo qual deverão entrar no útero onde o ambiente é mais propício. O transporte espermático na fêmea é o resultado da alta contratilidade, do movimento ciliar e o fluido do aparelho genital durante o estro, ao qual está sob controle endócrino e do sistema nervoso. Esse transporte é favorecido pelas características especiais do muco estral, cujas moléculas formam uma espécie de canais que facilitam a passagem dos espermatozoides. Pelo contrário, durante a fase lútea seu transporte é dificultado. Além do meio vaginal, a cérvix também atua como barreira natural para limitar a passagem dos espermatozoides, diminuindo assim a possibilidade de polispermia. Funciona, também, como um filtro que seleciona os espermatozoides aptos dos que não o são, uma vez que somente os primeiros possuem uma motilidade vigorosa que lhes permite passar pelo muco altamente hidratado. Na vaca a cérvix é considerada como um reservatório espermático. Quando atravessam a cérvix, os espermatozoides seguem sua deslocação tanto por movimento próprio como pelas contrações uterinas e tubárias. Nas espécies em que o local de depósito do sêmen do macho na fêmea é intrauterino, como equinos, a principal barreira que os espermatozoides enfrentam é a união ou junção útero-tubárica. A união entre o útero e o oviduto (istmo do oviduto) serve como reservatório funcional dos espermatozoides nas espécies domésticas. Poucos minutos depois da cópula, é possível encontrar alguns espermatozoides no oviduto, que é conhecido como fase de transporte rápido. No entanto, esses espermato-zoides não são os que participam do processo de fertilização e podem apresentar certas anormalidades. Existe um segundo tipo de transporte denominado fase sustentada, a qual consiste na migração prolongada dos espermatozoides em direção as partes mais craniais do aparelho genital feminino, que conduzem à colonização do reservatório funcional e na liberação gradual dos espermatozoides dos reservatórios espermáticos, incluindo este último. O reservatório do istmo fornece aos espermatozoides um ambiente propício, protegendo-os contra a fagocitose, prolongando assim a sua viabilidade. Aqui os esper-matozoides permanecem aderidos a superfície das células ciliadas do epitélio até a finalização de sua capacitação, depois da qual são liberados quando alteram seu padrão de motilidade flagelada, fenômeno conhecido como hipermotilidade, e migram em ondas em direção ao local da fertilização. Dos milhões de espermatozoides ejaculados, somente alguns milhares alcançarão o istmo do oviduto e um número sumamente pequeno será encontrado nas imediações do ovócito no momento da fertilização. -/- • _____CAPACITAÇÃO ESPERMÁTICA E REAÇÃO ACROSSÔMICA -/- A capacitação é um processo gradual e essencial para a fertilização. Os espermato-zoides devem passar por um dado tempo de “incubação” no aparelho genital da fêmea e sofrer uma série de mudanças antes de serem capazes de fecundar o ovócito. A capacita-ção dos espermatozoides começa quando eles entram em contato com as secreções do aparelho genital da fêmea e termina no istmo do oviduto. Durante esse percurso a superfície da cabeça do espermatozoide se modifica já que algumas moléculas como o colesterol são removidas da membrana plasmática, aumentando sua fluidez e alterando suas propriedades bioquímicas. Entre outras coisas, essa reorganização dos lipídios facilita a entrada de cálcio extracelular pelos canais iônicos e ocasiona a desestabilização da membrana, tornando-a mais fusogênica. Também são eliminados outros fatores (conhecidos genericamente como fatores descapacitantes) que expõem receptores membranais indispensáveis para a realização da união entre o espermatozoide e o ovócito durante a fertilização. Os espermatozoides capacitados apresentam um padrão de hipermotilidade e uma maior atividade metabólica, características que devem obter para que sejam capazes de penetrar as camadas do ovócito. A capacitação é necessária para que ocorra a reação acrossômica. A reação acrossomal ou acrossômica (RA) é um fenômeno de exocitose que é desencadeada pela ligação entre as proteínas e receptores localizados na membrana do espermatozoide e a zona pelúcida do ovócito (figura 3). Envolve a fusão da membrana plasmática do espermatozoide com a membrana externa de seu acrossomo; formando, assim, pequenas vesículas, cujo conteúdo de enzimas hidrolíticas, como a hialuronidase e a acrosina, é liberado em direção ao seu exterior, facilitando a penetração da zona pelúcida. A adesão do espermatozoide à zona pelúcida é específica da espécie e depende de glicoproteínas presentes na membrana dos ovócitos maduros; a cabeça do espermatozoide se une com essas glicoproteínas mediante receptores específicos e atravessam em direção oblíqua a zona pelúcida até chegar ao espaço perivitelino. Nos mamíferos, particularmente em roedores e nos humanos, algumas dessas glicoproteínas são conhecidas como ZP1, ZP2 e ZP3. Pensa-se que a união da membrana espermática a esta última é o que desencadeia a reação acrossomal. Posteriormente, as vilosidades do ovócito entram em contato com o espermatozoide e a membrana presente na secreção equatorial da cabeça do espermatozoide, que tem proteínas fusogênicas específicas, une-se a membrana plasmática do ovócito, fusionando-se e permitindo a entrada do núcleo espermático ao citoplasma (figura 4). A capacitação dos espermatozoides é fundamental para o êxito da fertilização, uma vez que apenas os aptos estarão perfeitos e íntegros para que a união e percepção das glicoproteínas presentes nos mesmos possam ocorrer de forma ideal para a penetração deste no ovócito, fertilizá-lo e formar um zigoto. Figura 3: estrutura do espermatozoide. Nota: a membrana é acrossomal e não acrossonal. Elaborado pelo autor. -/- Figura 4: eventos que ocorrem durante a fertilização. A – depois de passar através das células do cumulus, o espermatozoide entra em contato com a zona pelúcida, onde receptores da membrana plasmática reconhecem as proteínas da zona pelúcida; B – é desencadeada, então, a reação acrossomal; C – para que o espermatozoide penetre na zona pelúcida; D – ao atravessar a zona pelúcida e entrar no espaço perivitelino, a cabeça do espermatozoide entra em contato com a membrana vitelina; ambas membranas se fusionam graças ao reconhecimento de proteínas fusogênicas que estão no segmento equatorial. E – ocorre, então, que o núcleo do espermatozoide penetra no citoplasma do ovócito; uma das consequências da fusão da membrana com a cabeça do espermatozoide é a reação cortical, em que os grânulos corticais do ovócito liberam seu conteúdo em direção ao espaço perivitelino, o que resulta na alteração da estrutura da zona pelúcida e da membrana vitelina para bloquear a polispermia. Elaborado pelo autor. • _____CONSEQUÊNCIAS DA PENETRAÇÃO -/- Bloqueio da polispermia -/- A fusão das membranas dos gametas durante a penetração permite a entrada da fosfolipase C zeta (PLCζ) – fator solúvel que provém do espermatozoide – que desencadeia liberação e oscilações de Ca2+ no retículo endoplasmático. Isso, por sua vez, provoca a migração e fusão dos grânulos corticais, com a consequente liberação de enzimas, que mudam tanto a estrutura da zona pelúcida (por exemplo a inativação de ZP3), como a da membrana vitelina. Desse modo, impede-se que outros espermatozoides as penetrem, evitando assim a polispermia (figura 5). -/- Figura 5: os grânulos corticais que encontram-se na periferia do citoplasma, debaixo da superfície da membrana do ovócito, migram e fusionam-se sobre a mesma, liberando seu conteúdo no espaço perivitelino imediatamente depois da penetração do espermatozoide. A – como conse-quência, tanto a membrana vitelina como a zona pelúcida são modificadas, impedindo a entrada de mais espermatozoides, o que evita a polispermia. B – o ovócito retoma, então, sua segunda divisão meiótica, que ocasiona a expulsão do segundo corpúsculo polar, e na formação dos pronúcleos feminino e masculino. C – continuando, os pronúcleos migram, suas membranas se dissolvem e os cromossomos de ambos se condensam e se unem. Completa-se, assim, a singamia e forma-se, então, o zigoto. Elaborado pelo autor baseado nos livros de embriologia e fisiologia da reprodução conforme vida bibliografia. -/- Ativação do ovócito e formação de pronúcleos -/- Na maioria das fêmeas domésticas, com exceção da cadela, o ovócito encontra-se suspenso na metáfase II da segunda meiose no momento da ovulação. A entrada da PLCζ do espermatozoide no citoplasma do ovócito, e a consequente liberação de Ca2+, faz com que o ovócito se ative, terminando a segunda divisão meiótica e expulse o segundo corpo polar. Posteriormente, o material nuclear do ovócito se reorganiza para formar o pronú-cleo feminino. Entretanto, a membrana nuclear do espermatozoide se dissolve, a cromatina descondensa-se, as protaminas são substituídas por histonas, e se forma uma nova membrana nuclear, dando lugar ao pronúcleo masculino. -/- Singamia -/- Uma vez que os pronúcleos feminino e masculino são formados, migram para o centro do ovócito, aproximam-se, suas membranas se dispersam e os cromossomos paternos e maternos se associam, com o qual recupera a condição diploide e dá origem ao zigoto (figura 5). -/- • _____DESENVOLVIMENTO EMBRIONÁRIO -/- Poucas horas após a fertilização ocorre a primeira divisão do zigoto em duas, depois em 4, 8, 16 e 32 células, denominadas blastômeros. Essas divisões mitóticas são conhecidas como divisões de segmentação ou clivagem (figura 6), uma vez que são realizadas sem aumento do citoplasma, de modo que com cada divisão os blastômeros se tornam menores. A partir das 16 células o embrião se chama mórula, e é visto como uma massa celular compacta. A compactação deve-se a informação de proteínas de ligação entre os blastômeros. O embrião acumula líquido em seu interior, formando uma cavidade denominada blastocele. Esse processo é conhecido como blastulação; o embrião, assim, passa a ser chamado de blastocisto. Nessa etapa é possível diferenciar duas populações de células embrionárias: a massa celular interna, embrioblasto ou botão embrionário (que dará origem ao embrião), e a massa celular externa, células superficiais ou trofoblasto, do qual se originam a maioria das membranas fetais. Ao continuar a multiplicação das células e a acumulação de líquido, o blastocisto aumenta de tamanho, convertendo-se em blastocisto expandido. A zona pelúcida torna-se mais fina e, finalmente, o embrião eclode; isto é, o embrião é liberado da zona pelúcida. -/- • _____FERTILIZAÇÕES ATÍPICAS -/- Polispermia -/- É a penetração de dois ou mais espermatozoides no óvulo. Esta condição é letal nos mamíferos, já que o número cromossômico desse zigoto é maior que 2n, o envelheci-mento do ovócito da porca, como consequência do serviço tardio, favorece a apresentação da polispermia, por isso, é comum ver números de nascimentos de média de 10 a 12 leitões por parição nessa espécie. Nas aves, no entanto, a penetração de mais de um espermatozoide é normal, embora apenas um pronúcleo masculino se formará, fundindo-se com o feminino. -/- Figura 6: etapas do processo de segmentação/clivagem. Fonte: aula de reprodução da professora Domenica Palomaris, UFT. -/- Ginogênese -/- É o desenvolvimento de um embrião a partir de um óvulo normal fecundado por um espermatozoide, mas sem a fusão dos cromossomos masculinos com os da fêmea. A função do espermatozoide, nesse caso, é a de ativação do ovócito para que este inicie seu desenvolvimento, mas não há fusão com o núcleo do espermatozoide. Ocorre em plantas, em nematódeos e em algumas espécies de peixes, por exemplo a Poecilia formosa, espécie em que os ovócitos das fêmeas são ativados por machos de outra espécie relacio-nada. -/- Partenogênese -/- Consiste no desenvolvimento do embrião sem a participação do espermatozoide. Ocorre em alguns insetos, o zangão, por exemplo, é partenogenético. Também pode apresentar-se em perus, cujos embriões são machos e, geralmente, morrem antes da eclosão. -/- • _____GÊMEOS -/- Existem dois tipos de gêmeos: idênticos ou monozigóticos e os não idênticos ou dizigóticos. -/- Idênticos ou monozigóticos -/- Originam-se do mesmo zigoto, sendo assim, possuem o mesmo genótipo e um fenótipo similar e, portanto, são do mesmo sexo. Em laboratório é possível gerá-los ao seccionar uma mórula em duas ou mais partes, por meio de um micromanipulador. Uma vez que possuem o mesmo genótipo, os produtos resultantes são clones. -/- Não idênticos ou dizigóticos -/- Provêm da fertilização de dois óvulos distintos por espermatozoides diferentes. Possuem, portanto, genótipos e fenótipos diferentes, e podem ser de sexo diferente. -/- REFERÊNCIAS BIBLIOGRÁFICAS -/- ALBERTS, Bruce et al. Biologia molecular da célula. Artmed Editora, 2010. AUSTIN, Colin Russell; SHORT, Roger Valentine. Reproduction in Mammals, Book I: Germ Cells and Fertilization. 1982. BEARDEN, Henry Joe et al. Reproducción animal aplicada. México: Manual Moderno, 1982. BOSCH, P.; WRIGHT JR, R. W. The oviductal sperm reservoir in domestic mammals. Archivos de medicina veterinaria, v. 37, n. 2, p. 95-105, 2005. CAPALLEJAS, Roberto Brito; RODRÍGUEZ, Lourdes Tagle. Fisiología de la reproducción animal: con elementos de biotecnología. Editorial Félix Varela, 2010. CROXATTO, Horacio B. Physiology of gamete and embryo transport through the fallopian tube. Reproductive biomedicine online, v. 4, n. 2, p. 160-169, 2002. CUPPS, Perry T. (Ed.). Reproduction in domestic animals. Elsevier, 1991. DIEDRICH, Smidt et al. Endocrinología y Fisiología de la Reproducción de los Animales Zootécnicos. 1972. DUKES, Henry Hugh; SWENSON, Melvin J.; REECE, William O. Dukes fisiologia dos animais domésticos. Editora Guanabara Koogan, 1996. FERREIRA, A. de M. Reprodução da fêmea bovina: fisiologia aplicada e problemas mais comuns (causas e tratamentos). Juiz de Fora: Minas Gerais–Brasil, p. 422, 2010. HAFEZ, Elsayed Saad Eldin; HAFEZ, Bahaa. Reprodução animal. São Paulo: Manole, 2004. HUNTER, Ronald Henry Fraser. The Fallopian tubes in domestic mammals: how vital is their physiological activity?. Reproduction Nutrition Development, v. 45, n. 3, p. 281-290, 2005. HUNTER, R. H. F.; RODRIGUEZ‐MARTINEZ, H. Capacitation of mammalian spermatozoa in vivo, with a specific focus on events in the Fallopian tubes. Molecular Reproduction and Development: Incorporating Gamete Research, v. 67, n. 2, p. 243-250, 2004. GALINA, Carlos; VALENCIA, Javier. Reproducción de los animales domésticos. 2006. HOPPER, Richard M. (Ed.). Bovine reproduction. John Wiley & Sons, 2014. HYTTEL, Poul; SINOWATZ, Fred; VEJLSTED, Morten. Embriologia veterinária. Elsevier Brasil, 2012. KÖLLE, Sabine; REESE, Sven; KUMMER, Wolfgang. New aspects of gamete transport, fertilization, and embryonic development in the oviduct gained by means of live cell imaging. Theriogenology, v. 73, n. 6, p. 786-795, 2010. MCKINNON, Angus O. et al. (Ed.). Equine reproduction. John Wiley & Sons, 2011. OLIVERA, Martha et al. El espermatozoide, desde la eyaculación hasta la fertilización. Revista Colombiana de Ciencias Pecuarias, v. 19, n. 4, p. 426-436, 2006. PLANT, Tony M.; ZELEZNIK, Anthony J. (Ed.). Knobil and Neill's physiology of reproduction. New York: Academic Press, 2014. RODRIGUEZ-MARTINEZ, Heriberto. Role of the oviduct in sperm capacitation. Theriogenology, v. 68, p. S138-S146, 2007. SAAVEDRA LEOS, María Dolores. Estudio de la composición de los gránulos corticales y del oolema de ovocitos porcinos y bovinos madurados y fecundados in vitro. Proyecto de investigación:, 2010. SENGER, Phillip L. et al. Pathways to pregnancy and parturition. Current Conceptions, Inc, 2004. SUAREZ, Susan S. The oviductal sperm reservoir in mammals: mechanisms of formation. Biology of Reproduction, v. 58, n. 5, p. 1105-1107, 1998. VALENCIA MÉNDEZ, Javier de J. Fisiología de la reproducción porcina. 1986. -/- FIXAÇÃO DO ASSUNTO -/- 1. Defina e diferencie fertilização e segmentação. -/- 2. Disserte sobre o transporte do ovócito. Por que no istmo o transporte do ovócito se torna lento? -/- 3. Fale sobre a eficiência do transporte do gameta no trato genital da fêmea e sobre a retenção de ovócitos pela égua. -/- 4. Defina as células do cumulus e explique seu papel sobre o ovócito. -/- 5. Quais as estruturas que compõem o ovócito? Qual a função de cada uma? -/- 6. Todos os ovócitos das fêmeas domésticas são iguais? Justifique. -/- 7. Disserte sobre o papel dos hormônios e das secreções sobre o transporte do ovócito no trato genital da fêmea. -/- 8. Disserte sobre o transporte do espermatozoide. Por que há transporte rápido e lento dos espermatozoides? -/- 9. Fale sobre o local de deposição do sêmen nas espécies domésticas e como esse influen-cia na eficiência da reprodução. -/- 10. Por que a vida média do espermatozoide canino é maior que as outras espécies? -/- 11. Quais as mudanças que os espermatozoides precisam sofrer para conseguir êxito na fertilização e por quê? -/- 12. Defina fase de transporte rápido, fase sustentada e hipermotilidade. Qual a importân-cia de cada um? -/- 13. Como ocorre a reação acrossômica? -/- 14. O que é polispermia e como ocorre seu bloqueio? 15. Como ocorre a ativação do ovócito e como se formam os pronúcleos? -/- 16. O que é e qual a importância da singamia? -/- 17. Disserte sobre as divisões de segmentação e qual a importância destas para o êxito da reprodução. -/- 18. Defina e diferencia mórula e blastocisto. -/- 19. Defina e diferencie ginogênese e partenogênese. -/- 20. Qual o papel endócrino e quais hormônios e enzimas atuam sobre o transporte de gametas, sobre a fertilização e sobre a segmentação? (shrink)

(Updated 5/23/24) This unpublished paper, which readers should feel free to cite, is posted primarily for the historical record. In recent work that has, deservedly, received some attention, Paul R. Daniels presents and defends a non-standard theory of persistence that he dubs transdurantism, according to which persisting objects are temporally extended simples. This is exactly what I do in work dating back to Spring 2004. (This work includes this version of this paper, as well as later version that was presented (...) to the University of Rochester's Philosophy Department in 2005.) While this might be a total coincidence, I doubt that it is, especially given that 'transdurantism' appears as a name for a theory of persistence associated with me in at least two places in the literature, one of which includes a citation of this paper. The paper begins with a discussion of what I call 'locative relations' (the relations borne by material objects to the regions of space and time they occupy), which draws relevant distinctions that others have failed to draw. The results of this discussion are then used in constructing spatial analogues for the three established theories of persistence--endurantism, perdurantism, and exdurantism--as well as for transdurantism. Next, these four views concerning persistence are explicitly formulated and a defense of their formulation is offered. Finally, transdurantism's advantages and disadvantages relative to the other theories are discussed. The main goal of the paper is to challenge the trichotomy between the established theories by arguing that transdurantism is also a viable view concerning persistence through time. [Note: Befitting its status as a historical document, with the exception of some light editing to fix typos that might impede understanding, no changes have been made to the paper.]. (shrink)

In my dissertation, I address a variety of issues in the metaphysics of space and related areas. I begin by discussing the popular thesis that regions of space are identical to sets of points in space. I present three arguments against this thesis and conclude that we should be skeptical of it. In its place, I propose an axiomatic theory of regions of space that is consistent with both reductive accounts of their nature and with accounts that treat them as (...) sui generis entities. -/- I next explore the consequences of the aforementioned considerations. In particular, I describe five different sorts of structure each of which is such that the claim that space could have that structure is consistent with the axiomatic theory previously proposed. I claim that this fact, together with the skepticism concerning reductive accounts argued for earlier, shows that we should take seriously the claim that space could have any of these structures. -/- Having argued that we should be skeptical of the thesis that regions of space are identical to sets of points in space and suggesting that space could have different sorts of structure, I discuss how best to analyze continuity. I present an analysis of continuity inspired by remarks of Richard Cartwright in his 1975 paper ‘Scattered Objects’. I argue that this Cartwrightian analysis should be rejected because it identifies regions of space with sets of points in space, and I present a modified version of the analysis that does not do so. I note, however, that there is an intuitive notion of continuity that is not captured by this modified Cartwrightian analysis. I present and defend an analysis of continuity that better captures this intuitive notion. -/- I then turn to the issue of how to analyze what it is for a region of space to be open and what it is for a region of space to be closed. Here I argue that Cartwright’s analyses of these notions are incorrect. I then present a series of alternative analyses, revising each in response to objections. This process culminates with my proposed analyses of what it is for a region of space to be open and what it is for a region of space to be closed. -/- Finally, I discuss the Maximally Continuous Account of Simples (MaxCon), originally formulated and defended by Ned Markosian in his 1998 paper ‘Simples’. I argue that Markosian’s version of MaxCon, which identifies regions of space with sets of points in space and relies on the Cartwrightian analysis of continuity, should be rejected. I then formulate a new version of MaxCon that builds on the views defended earlier in my dissertation and defend this new version of MaxCon from objections. (shrink)

Dedication: I would like to dedicate this essay to Mort Morehouse, whose intelligence, warmth, and good humour sustains NAACI to this day. I would like, too, to dedicate this essay to Nadia Kennedy who, in her paper “Respecting the Complexity of CI,” suggests that respect for the rich non-reductive emergent memories and understandings that evolve out of participating in the sort of complex communicative interactions that we experienced at the 2012 NAACI conference requires “a turning around and looking back so (...) that we might understand it better.” Thus, though “we cannot grasp the essence of the system in some determinate way, since each description provides a limited view, and portrays some aspect of the system from a specific position inside or outside it, and at a specific point in time,” nonetheless respect requires that we try “to take different ‘snapshots’ of such systems and attempt to make sense of them.” It is as a result of this urging that the following snapshot was attempted. My thanks to Nadia for being such an inspiration, and to all the participants for making this conference such a memorable occasion. (shrink)

It is plausible that the universe exists: a thing such that absolutely everything is a part of it. It is also plausible that singular, structured propositions exist: propositions that literally have individuals as parts. Furthermore, it is plausible that for each thing, there is a singular, structured proposition that has it as a part. Finally, it is plausible that parthood is a partial ordering: reflexive, transitive, and anti-symmetric. These plausible claims cannot all be correct. We canvass some costs of denying (...) each claim and conclude that parthood is not a partial ordering. Provided that the relevant entities exist, parthood is not anti-symmetric and proper parthood is neither asymmetric nor transitive. (shrink)

This is the text of Dr. Sterrett's replies to an interviewer's questions for simplycharly.com, a website with interviews by academics on various authors, philosophers, and scientists.

We discuss the view that a hole is identical to the region of spacetime at which it is located. This view is more parsimonious than the view that holes are sui generis entities located at those regions surrounded by their hosts and it is more plausible than the view that there are no holes. We defend the spacetime view from several objections.

This chapter is a work in applied metaphysics. Recent discussions of monism and metaphysical dependence are deployed to develop a view—the doctrine of divine priority (DDP)—that is a viable alternative to the doctrine of divine simplicity (DDS). DDS and the traditional motivation for it are discussed, then DDP is introduced by way of an analogy involving Jonathan Schaffer’s distinction between two forms of monism. It is argued that DDP is an alternative to DDS by showing that it is consistent with (...) the traditional motivation for the latter view, and argued that DDP is a viable alternative by showing that objections to its peculiar implications rest on assumptions that can reasonably be rejected. In the concluding section, the findings of the main discussion are summarized and DDP’s potential theological import is illustrated with a brief discussion of a possible solution to the Problem of the Trinity it affords. (shrink)

I argue against the Primary Sound Account of Echoes (PSAE) – the view that an echo of a sound just is that sound. I then argue that if my case against PSAE is successful, distal theories of sound are false. The upshot of my arguments, if they succeed, is that distal theories are false. Towards the end, I show how some distal theories can be modified to avoid this conclusion and note some open questions to which the modified theories give (...) rise. (shrink)

Lesbian organizations have frequently cited the concept of a Lesbian Nation as an ideal community where women could be freed from the oppression of relationships with men. The term was used in speeches made by lesbian activists beginning in the 1970s. However, lesbian militant activities have increasingly merged with the overall gay civil rights movement, so that most activists have preferred to use the term Queer Nation to refer to the movement in general.

If you cannot, then you ought not. Taking its own precepts seriously, philosophy, in the face of scientific deterministic success, has abandoned its original calling of inspiring munificence and, in doing so, has undercut much of its own relevance. But this need not be the case. If we adopt a more finely grained set of theoretical glasses, we will see that human freedom is simply the icing on a deterministic layer cake that launches entities, both phylogenetically and ontogenetically, from the (...) object base, through consciousness, and then through self-consciousness, and finally to the possibility of reasonably based self-legislation. Greasing the wheels of the last step is Philosophy’s calling and responsibility. We can—and we ought because we can—fall inline with the Socratic echo, and agitate for munificence. (shrink)

There are kinds of dialogue that support social justice and others that do the reverse. The kinds of dialogue that supports social justice requires that anger be bracketed and that hiding in safe spaces be eschewed. All illegitimate ad hominem/ad feminem attacks are ruled out from the get-go. No dialogical contribution can be down-graded on account of the communicator’s gender, race, or religion. As well, this social justice communicative approach unapologetically privileges reason in full view of theories and strategies that (...) might seek to undermine reasoning as just another illegitimate form of power. -/- On the more positive side, we will argue that social justice dialogue will enhanced by a kind of “communicative upgrading” that amplifies “person perception,” foregrounds the impersonal forces within our common social spaces rather than the “baddies” within, and orients the dialogical trajectory toward the future rather than the past. Finally, we will argue that educators have a pressing responsibility to guide their students through social justice dialogue so that their contributions contribute to the amelioration of injustice, rather than rendering the terrain more treacherous. (shrink)

Many academic works as well as many works of art are such that if they had never been produced, no one would be worse off. Yet it is hard to resist the judgment that some such works are good nonetheless. We are rightly grateful that these works were created; we rightly admire them, appreciate them, and take pains to preserve them. And the authors and artists who produced them have reason to be proud. This should lead us to question the (...) view that in order for a thing to be good, in a sense which implies that the thing merits our attention and positive concern, it needs to be good for someone or something whose welfare is enhanced by it. (shrink)

A critical survey of various positions on the nature, use, possession, and analysis of normative concepts. We frame our treatment around G.E. Moore’s Open Question Argument, and the ways metaethicists have responded by departing from a Classical Theory of concepts. In addition to the Classical Theory, we discuss synthetic naturalism, noncognitivism (expressivist and inferentialist), prototype theory, network theory, and empirical linguistic approaches. Although written for a general philosophical audience, we attempt to provide a new perspective and highlight some underappreciated problems (...) about normative concepts. (shrink)

In the face of disobedience, and in the name of the short-term goal of a smooth-functioning and/or happy household, parents often feel caught between two diametrically opposed parenting strategies; make it happen or let it go. However, either strategy of dictator or friend can seriously jeopardize a child’s long-term best interests. If children, adolescents, young adults, full adults or oldsters are even to hear, let alone reasonably answer, the prudential and ethical “whys” that their intended actions scream, they will need (...) to attend to health of their unique human capacity to reason. They will need to understand deeply that reason is not a capacity to be used solely in academic endeavors and/or for making a living, but rather that reason’s prime function is to assist in making the best of all possible lives. If parents want their children to understand this, then they need to walk the talk and invite reason into their homes. The result will be that authoritarian parents will need to let go, while “parents as friends” will need to belly up to the bar, in order to entrench the first rule of a reasonable household and that is that the best reason always wins. (shrink)

Suicide is a complex act whose meanings, while sometimes tragic, vary widely. This chapter surveys the ethical landscape surrounding algorithmic methods of suicide prevention especially as it pertains to social media activity and to the moderation of online suicide communities. We begin with a typology of suicide, distinguishing between varied goals in which suicide may factor as a means. Suicides should be understood as an act with varied eliciting desires, meanings, consequences, and ethics. Further,while many suicides may be grounded on (...) irrational desire, we argue that a desire to suicide may nonetheless be rational in some cases. We then offer a survey of the attempts by social media corporations to create suicide prediction algorithms and launch interventions aimed at preventing suicide as well as an overview of the current ethical debate. We argue that the values embedded within algorithmic suicide prevention nudges are “thick” in a substantive sense and deserving of scrutiny. Given that debates about the rationality, meaning, and permissibility of suicide are common and subject to intracultural and cross-cultural differences, we maintain that the task of suicide prediction is ill-suited to algorithmic approaches. Despite an algorithm’s ability to quantify a complex phenomenon like suicide risk and its appearance of objectivity, any suicide prediction algorithm is thoroughly subjective and involves moral judgments all the way down. Any such algorithm would necessarily impose a normative stance on suicide onto its user base that is subject to reasonable intra and cross-cultural disagreement. (shrink)

Skeptical theists are seeking for some reasonable solutions to the evidential problem of evil. One of the most fundamental responses of skeptical theism is that the concept of “gratuitous evil”, which cannot be a proof of the absence of God. Therefore, it is not the existence of God that skeptical theism suspects. Instead, skeptical theism contemplates whether the evil in the world really has a “gratuitous” basis. This paper focuses on Peter van Inwagen's “no-minimum claim”. No-minimum claim” stands in opposition (...) to the views that assume that God minimizes the evils that exist in the world in order to achieve justice. “No-minimum claim” acknowledges that these evils still have enormous amounts to people. Thus “no-minimum claim” suggests that the evils experienced in the world are incompatible with the “best of all possible worlds” views or the other explanations of classical theodicy. According to the “no minimum claim”, the reason why the amount of evil in the world still seems so high may be God’s deliberate calculations in effecting the distribution of these evils. In order to reach these calculations, it is not necessary for the amount of evil that God allowed to reflect on the world to be perfectly manifested at the minimum level. The purpose of this paper is to consider the skeptical theism approach within the framework of Peter van Inwagen's “no-minimum claim” and to limit his arguments to an alternative approach to skeptic theism. Our claim is that such view coincides with skeptical theism, but the “no- minimum claim” still has some ambiguities at the point of the limits of evil. From this, we can conclude that the “no minimum claim” has received many objections in the skeptical theism literature and these objections are justified at certain points. (shrink)

As the English word “scientism” is currently used, it is a trivial verbal truth that scientism—an inappropriately deferential attitude to science—should be avoided. But it is a substantial question when, and why, deference to the sciences is inappropriate or exaggerated. This paper tries to answer that question by articulating “six signs of scientism”: the honorific use of “science” and its cognates; using scientific trappings purely decoratively; preoccupation with demarcation; preoccupation with “scientific method”; looking to the sciences for answers beyond their (...) scope; denying the legitimacy or worth of non-scientific (e.g., legal or literary) inquiry, or of writing poetry or making art. (shrink)

In this analysis of one of the most difficult and neglected topics in Hegelian studies, Songsuk Susan Hahn tackles the status of contradiction in Hegel's ...

While artificial womb technology is currently being studied for the purpose of improving neonatal care, I contend that this technology ought to be pursued as a means to address the unprecedented rate of unintended pregnancies. But ectogenesis, alongside other emerging reproductive technologies, is problematic insofar as it threatens to disrupt the natural link between procreation and parenthood that is normally thought to generate rights and responsibilities for biological parents. I argue that there remains only one potentially viable account of parenthood: (...) the voluntarist account, which construes parental rights as robust moral obligations that must be voluntarily undertaken. The problem is that this account mistakenly presumes a patriarchal divide between procreation and parenthood. I propose a reframing of procreation and parenthood from a feminist perspective that recognises gestational motherhood as involving robust moral obligations that ought to be voluntarily undertaken. If this were the case, all gestational mothers would be, by definition, willing mothers. To make this happen I argue that ectogenesis technology must be a widely available reproductive option. (shrink)

We live in an age in which outer space has changed from a theme for flights of science fiction to the actual locus of exploration and travel.1 Space no longer has merely speculative significance for thinking about possible worlds; it has become a real factor in understanding the nature and conditions of the human world that we are constantly refashioning. Our entry into outer space brings with it changes in conditions and experience that require us to rethink the concepts through (...) which we comprehend environment and act environmentally. (shrink)

There are kinds of dialogue that support social justice and others that do the reverse. The kinds of dialogue that support social justice require that anger be bracketed and that hiding in safe spaces be eschewed. All illegitimate ad hominem/ad feminem attacks are ruled out from the get-go. No dialogical contribution can be down-graded on account of the communicator’s gender, race, or religion. As well, this communicative approach unapologetically privileges reason in full view of theories and strategies that might seek (...) to undermine reasoning as just another illegitimate form of power. On the more positive side, it is argued in this paper that social justice dialogue will be enhanced by a kind of “communicative upgrading,” which amplifies “person perception,” foregrounds the impersonal forces within our common social spaces rather than the “baddies” within, and orients the dialogical trajectory toward the future rather than the past. Finally, it is argued in this paper that educators have a pressing responsibility to guide their students through social justice dialogue so that their speech contributes to the amelioration of injustice, rather than rendering the terrain more treacherous. (shrink)

I develop a cognitive account of how humans make skeptical judgments (of the form “X does not know p”). In my view, these judgments are produced by a special purpose metacognitive "skeptical" mechanism which monitors our reasoning for hasty or overly risky assumptions. I argue that this mechanism is modular and shaped by natural selection. The explanation for why the mechanism is adaptive essentially relies on an internalized principle connecting knowledge and action, a principle central to pragmatic encroachment theories. I (...) end the paper by sketching how we can use the account I develop here to respond to the skeptic. (shrink)

Summary Analogue models are actual physical setups used to model something else. They are especially useful when what we wish to investigate is difficult to observe or experiment upon due to size or distance in space or time: for example, if the thing we wish to investigate is too large, too far away, takes place on a time scale that is too long, does not yet exist or has ceased to exist. The range and variety of analogue models is too (...) extensive to attempt a survey. In this article, I describe and discuss several different analogue model experiments, the results of those model experiments, and the basis for constructing them and interpreting their results. Examples of analogue models for surface waves in lakes, for earthquakes and volcanoes in geophysics, and for black holes in general relativity, are described, with a focus on examining the bases for claims that these analogues are appropriate analogues of what they are used to investigate. A table showing three different kinds of bases for reasoning using analogue models is provided. Finally, it is shown how the examples in this article counter three common misconceptions about the use of analogue models in physics. (shrink)

Deleuze’ün Spinozacı yaşam tahayyülünde ‘ne yapmalıyız?’ sorusuna normatif, ahlaki ya da siyasi bir yanıt bulamıyoruz ama varoluşu düşünmenin içkin bir olanağını keşfediyoruz. Düşünmeye 'dışarıdan' yani dünyadan başlamak insani (kurgusal) bir dünyaya değil, içinde yaşadığımız gerçek dünyaya inanmak demektir. İçkinliğin politik anlamı düşünceyi dünyaya getirmektir.

The concept of similar systems arose in physics, and appears to have originated with Newton in the seventeenth century. This chapter provides a critical history of the concept of physically similar systems, the twentieth century concept into which it developed. The concept was used in the nineteenth century in various fields of engineering, theoretical physics and theoretical and experimental hydrodynamics. In 1914, it was articulated in terms of ideas developed in the eighteenth century and used in nineteenth century mathematics and (...) mechanics: equations, functions and dimensional analysis. The terminology physically similar systems was proposed for this new characterization of similar systems by the physicist Edgar Buckingham. Related work by Vaschy, Bertrand, and Riabouchinsky had appeared by then. The concept is very powerful in studying physical phenomena both theoretically and experimentally. As it is not currently part of the core curricula of STEM disciplines or philosophy of science, it is not as well known as it ought to be. (shrink)

There is a long standing controversy in education as to whether education ought to be teacher- or student- centered. Interestingly, this controversy parallels the parent- vs. child-centered theoretical swings with regard to good parenting. One obvious difference between the two poles is the mode of communication. “Authoritarian” teaching and parenting strategies focus on the need of those who have much to learn to “do as they are told,” i.e. the authority talks, the child listens. “Non-authoritarian” strategies are anchored in the (...) assumption that youngsters ought to be encouraged to develop their natural interests and talents and hence that it is important to allow the children to do the talking and that adults listen. Both strategies seemed flawed due to the absence of the inherent wisdom of its opposing view. This chasm can be overcome. The Community of Inquiry, a pedagogical method used in Philosophy for Children, demands a method of communication which is able to bridge this gap. A Community of Inquiry is neither teacher-centered and controlled nor student-centered and controlled, but centered on and controlled by the demands of truth. Truth is absolutely essential to this method; it is only because of progress toward truth that participants are ultimately convinced of the fruitfulness of the process. Truth, however, is a hard taskmaster; it places severe restrictions on participants and puts exacting demands on the facilitator. These inherent restrictions and demands are too often underplayed, overlooked and sometimes seemingly overtly denied by those who, quite correctly emphasize that ultimately this method depends on maintenance and enhancement of student autonomy. This underrating of the role of the facilitator has led to a severe undervaluing of this otherwise brilliant pedagogical method, but worse, it has left novice teacher/facilitators ill prepared to utilize this method successfully. (shrink)

In this paper I challenge recent externalist interpretations of Ockham’s theory of intuitive cognition. I begin by distinguishing two distinct theses that defenders of the externalist interpretation typically attribute to Ockham: a ‘direct reference thesis’, according to which intuitive cognitions are states that lack all internal, descriptive content; and a ‘causal thesis’, according to which intuitive states are wholly determined by causal connections they bear to singular objects. I then argue that neither can be plausibly credited to Ockham. In particular, (...) I claim that the causal thesis doesn’t square with Ockham’s account of supernaturally produced intuition and that the direct reference thesis sits uneasily with Ockham’s characterization of the intentional structure of intuitive states. (shrink)

The tragedy of the commons is a primary contributing factor in ensuring that humanity makes no serious inroads in averting climate change. As a recent Canadian politician pointed out, we could shut down the Canadian economy tomorrow, and it would make no measurable difference in global greenhouse gas emissions. When coordinated effort is required, it would seem that doing the “right thing” alone is irrational: it will harm oneself with no positive consequences as a result. Such is the tragedy. And (...) that is the challenge that we take up here. Though Garrett Hardin suggests that the solution is a governmental process that rules over all contenders, since a world government seems unlikely before the planet hits the tippy point, we suggest an educational initiative instead: one that holds a mirror up to the behaviour of individuals, rather than to the behaviour of individuals in groups. Such an educational initiative would be focused on priming individuals to keep constant track of what they do as individuals as opposed to focusing on the behaviour of humanity in general. Such an educational initiative would focus on tackling the “problem solvers” rather than just “the problem”. (shrink)

If successful scientific inquiry is to be possible, there must be a world that is independent of how we believe it to be, and in which there are kinds and laws; and we must have the sensory apparatus to perceive particular things and events, and the capacity to represent them, to form generalized explanatory conjectures, and check how these conjectures stand up to further experience. Whether these preconditions are met is not a question the sciences can answer; it is specifically (...) philosophical. This is why the myriad forms of scientistic philosophy in vogue today (neurophilosophy, experimental philosophy, naturalized metaphysics, evangelical-atheist reductionism, etc), are all hollow at the core. Does this mean we must return to the old, a priori analytic model? No! What is needed instead is scientific philosophy in the sense Peirce articulated more than a century ago: philosophy motivated by a genuine desire to discover the truth, and relying not solely on reason but also on experience—only not the special, recherché experience required by the sciences, but close attention to aspects of everyday experience so familiar we hardly notice them. (shrink)

There is a clear distinction between genuine and fraudulent reasoning. Being seduced by the latter can result in horrific consequences. This paper explores how we can arm ourselves, and others with the ability to recognize the difference between genuine and pseudo-reasoning, with the motivation to maintain an unbending commitment to follow the “impersonal” “norm-driven” rules of reason even in situations in which “non-reasonable” strategies appear to support short-term bests interests, and with the confidence that genuine reasoning is the best defense (...) against the pseudo-reasoning. It also provides a simple table of “markers” whereby genuine reasoning can be distinguished from the “fake stuff.”. (shrink)

On a literal reading of `Computing Machinery and Intelligence'', Alan Turing presented not one, but two, practical tests to replace the question `Can machines think?'' He presented them as equivalent. I show here that the first test described in that much-discussed paper is in fact not equivalent to the second one, which has since become known as `the Turing Test''. The two tests can yield different results; it is the first, neglected test that provides the more appropriate indication of intelligence. (...) This is because the features of intelligence upon which it relies are resourcefulness and a critical attitude to one''s habitual responses; thus the test''s applicablity is not restricted to any particular species, nor does it presume any particular capacities. This is more appropriate because the question under consideration is what would count as machine intelligence. The first test realizes a possibility that philosophers have overlooked: a test that uses a human''s linguistic performance in setting an empirical test of intelligence, but does not make behavioral similarity to that performance the criterion of intelligence. Consequently, the first test is immune to many of the philosophical criticisms on the basis of which the (so-called) `Turing Test'' has been dismissed. (shrink)

The Future of Social Epistemology: A Collective Vision sets an agenda for exploring the future of what we – human beings reimagining our selves and our society – want, need and ought to know. The book examines, concretely, practically and speculatively, key ideas such as the public conduct of philosophy, models for extending and distributing knowledge, the interplay among individuals and groups, risk taking and the welfare state, and envisioning people and societies remade through the breakneck pace of scientific and (...) technological change. An international team of contributors offers a ‘collective vision’, one that speaks to what they see unfolding and how to plan and conduct the dialogue and work leading to a knowable and desirable world. The book describes and advances an intellectual agenda for the future of social epistemology. (shrink)

After the 2016 election of Donald Trump, many commentators latched on to the accusations Rorty levels at the American Left in Achieving Our Country. Rorty foresaw, they claimed, that the Left's preoccupation with cultural politics and neglect of class politics would lead to the election of a "strongman" who would take advantage of and exploit a rise in populist sentiment. -/- In this paper, I generally agree with these readings of Rorty; he does think that the American Left has made (...) the mistake of putting class on the political backburner. However, I suggest that this position follows from his view that economic security is vital for solidarity. Because economic security is under increasing threat in contemporary America, so too is solidarity. If greater solidarity is a goal of liberal democracy, then class politics, aimed at ending selfishness, ought to be as much a priority for the American Left as is cultural politics, aimed at ending sadism. (shrink)

Misrepresentations can be innocuous or even useful, but Kant’s corollary to the formula of universal law appears to involve a pernicious one: “act as if the maxim of your action were to become by your will a universal law of nature”. Humans obviously cannot make their maxims into laws of nature, and it seems preposterous to claim that we are morally required to pretend that we can. Given that Kant was careful to eradicate pernicious misrepresentations from theoretical metaphysics, the imperative (...) to act as if I have this supernatural power has typically been treated as an embarrassment meriting apology. The wording of the corollary may be vindicated, however, by recognizing that “as if” (als ob) is a technical term both in the Critique of Pure Reason and here. It signals a modal shift from the assertoric to the problematic mode of cognition, one that is necessitated by the attempt to incorporate the natural effects of a free will into a universal moral imperative that is philosophically practical. In this paper I sketch how the modal shift makes sense of the corollary as a subjectively necessary, philosophically practical idealization of the extension of human freedom into nature, one that accurately represents a necessary parameter of moral conduct: moral ambition. (shrink)

Given that one of the major goals of the practice of Philosophy for Children (P4C) is the development of critical thinking skills (Sharp 1987/2018, pp. 4 6), an urgent question that emerged for one of the authors, who is of Chinese Heritage and a novice practitioner at a P4C summer camp was whether this emphasis on critical thinking might make this practice incompatible with the fabric of Chinese culture. Filial piety (孝), which requires respect for one’s parents, elders, and ancestors (...) is considered an important virtue in Asian culture, as is the preservation of harmony. But if one of the goals of P4C is to teach youngsters to courageously pursue reasoned dialogue, does this not set-up young Asians for serious conflict when they come face-to-face with positions that are articulated by elders, but which are ones to which they are diametrically opposed; a racist grandmother, for instance, or an uncle who insists that those at the Tiananmen Square uprising were nothing but hooligan’s. It is this question that we will explore in this presentation. In the process, we will come to the conclusion that, when positions seem irreconcilable, rather than continuing to pursue rigorous critical interchange that may do little other than escalate insult, the facilitator, rather, ought to move toward creating a deeper understanding of each position juxtaposed against its opposing view (a process that we refer to as ‘collaborative caring’), so as to produce side-by-side understanding, knowing that communal bonds have been maintained and, hence, that the opportunity for genuine reasoned collaborative inquiry on other issues and at future times remains open. (shrink)

This book is an invitation to academic administrators, at every level, to engage in reflection on the ethical dimensions of their working lives.

During the past decades, our image ofHomo neanderthalensishas changed dramatically. Initially, Neanderthals were seen as primitive brutes. Increasingly, however, Neanderthals are regarded as basically human. New discoveries and technologies have led to an avalanche of data, and as a result of that it becomes increasingly difficult to pinpoint what the difference between modern humans and Neanderthals really is. And yet, the persistent quest for a minimal difference which separates them from us is still noticeable in Neanderthal research. Neanderthal discourse is (...) a vantage point from which the logic of ‘us’ versus ‘other’ is critically reconsidered. Studying contemporary academic literature and science autobiographies from an oblique perspective, focusing not on Neanderthals as objects, but on the dynamics of interaction between Neanderthal researchers and their finds, basic convictions at work in this type of research are retrieved. What is at issue is not the actual distinction between modern humans and Neanderthals, but rather the dualistic construction of human and nonhuman. Neanderthal understanding is affected by the desire to safeguard human uniqueness. The overall trend is to identify the human mark or spark, which defines us as favoured ‘winners’. The paradoxes emerging in contemporary Neanderthal discourse are symptomatic of the fact that a dualistic style of thinking is no longer tenable. (shrink)

The Language of Thought program has a suicidal edge. Jerry Fodor, of all people, has argued that although LOT will likely succeed in explaining modular processes, it will fail to explain the central system, a subsystem in the brain in which information from the different sense modalities is integrated, conscious deliberation occurs, and behavior is planned. A fundamental characteristic of the central system is that it is “informationally unencapsulated” -- its operations can draw from information from any cognitive domain. The (...) domain general nature of the central system is key to human reasoning; our ability to connect apparently unrelated concepts enables the creativity and flexibility of human thought, as does our ability to integrate material across sensory divides. The central system is the holy grail of cognitive science: understanding higher cognitive function is crucial to grasping how humans reach their highest intellectual achievements. But according to Fodor, the founding father of the LOT program and the related Computational Theory of Mind (CTM), the holy grail is out of reach: the central system is likely to be non-computational (Fodor 1983, 2000, 2008). Cognitive scientists working on higher cognitive function should abandon their efforts. Research should be limited to the modules, which for Fodor rest at the sensory periphery (2000).1 Cognitive scientists who work in the symbol processing tradition outside of philosophy would reject this pessimism, but ironically, within philosophy itself, this pessimistic streak has been very influential, most likely because it comes from the most well-known proponent of LOT and CTM. Indeed, pessimism about centrality has become assimilated into the mainstream conception of LOT. (Herein, I refer to a LOT that appeals to pessimism about centrality as the “standard LOT”). I imagine this makes the standard LOT unattractive to those philosophers with a more optimistic approach to what cognitive science can achieve.. (shrink)

Hud Hudson has argued that if MaxCon, Ned Markosian's favored answer to the Simple Question, is true, then there couldn't be gunky objects. If Hudson's argument succeeds, then those who believe that gunky objects are possible have a good reason to reject MaxCon. However, I show that Hudson's argument relies on substantive metaphysical claims that a proponent of MaxCon need not accept. Thus, one who endorses MaxCon need not reject the possibility of gunky objects and those who believe that gunky (...) objects are possible need not reject MaxCon. (shrink)

Exclusionary defeat is Joseph Raz’s proposal for understanding the more complex, layered structure of practical reasoning. Exclusionary reasons are widely appealed to in legal theory and consistently arise in many other areas of philosophy. They have also been subject to a variety of challenges. I propose a new account of exclusionary reasons based on their justificatory role, rejecting Raz’s motivational account and especially contrasting exclusion with undercutting defeat. I explain the appeal and coherence of exclusionary reasons by appeal to commonsense (...) value pluralism and the intermediate space of public policies, social roles, and organizations. We often want our choices to have a certain character or instantiate a certain value and in order to do so, that choice can only be based on a restricted set of reasons. Exclusion explains how pro tanto practical reasons can be disqualified from counting towards a choice of a particular kind without being outweighed or undercut. (shrink)