Responds to the article by Brad Brown and Susan Perry in the August 1995 issue of `Business & Society' periodical on the measure of corporate social responsibility (CSP).

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)

In my article "Even if the fetus is not a person, abortion is immoral: The impairment argument" (this journal), I defended what I called “The impairment argument” which purports to show that abortion is immoral. Bruce Blackshaw (2019) has argued that my argument fails on three accounts. In this article, I respond to his criticisms.

Much of the discussion surrounding the ethics of abortion has centered around the notion of personhood. This is because many philosophers hold that the morality of abortion is contingent on whether the fetus is a person - though, of course, some famous philosophers have rejected this thesis (e.g. Judith Thomson and Don Marquis). In this article, I construct a novel argument for the immorality of abortion based on the notion of impairment. This argument does not assume that the fetus is (...) a person - indeed, I concede (for the sake of argument) that the fetus is not a person - and hence the morality of abortion is not contingent on whether the fetus is a person. I finish by answering a plethora of objections to my argument, concluding that none of them are successful. (shrink)

Arguments from evil purport to show that some fact about evil makes it (at least) probable that God does not exist. Skeptical theism is held to undermine many versions of the argument from evil: it is thought to undermine a crucial inference that such arguments often rely on. Skeptical objections to skeptical theism claim that it (skeptical theism) entails an excessive amount of skepticism, and therefore should be rejected. In this article, I show that skeptical objections to skeptical theism have (...) a very limited scope: only those who reject certain (apparently) popular epistemological theories will be threatened by them. (shrink)

Joona Räsänen, in his article ‘Ectogenesis, abortion and a right to the death of the fetus’, has argued for the view that parents have a right to the death of the fetus. In this article, I will explicate the three arguments Räsänen defends, and show that two of them have false or unmotivated premises and hence fail, and that the support he offers for his third argument is inconsistent with other views he expresses in his article. Therefore, I conclude that (...) there is no right to the death of the fetus—or, if there is one, Räsänen has not shown it. (shrink)

It is often assumed that if the fetus is a person, then abortion should be illegal. Thomson1 laid the groundwork to challenge this assumption, and Boonin2 has recently argued that it is false: he argues that abortion should be legal even if the fetus is a person. In this article, I explain both Thomson’s and Boonin’s reason for thinking that abortion should be legal even if the fetus is a person. After this, I show that Thomson’s and Boonin’s argument for (...) legalised abortion fail; they have not given us good reason for thinking abortion should be legal.1 Finally, I argue that—if we play Boonin’s game—abortion should be illegal. When discussing the ethics and politics of abortion, whether the fetus is a person is usually central.3 4.2 However, Thomson1 long ago challenged this view. She argued that abortion is permissible even if the fetus is a person. To do so, she asks us to consider a case in which you are non-consensually taken to a hospital and hooked up to a famous violinist. The violinist, if he is to survive, needs to filter his blood through your body. After 9 months, he will be fine and you can unplug yourself and go on your way. If you unplug yourself prior to this, however, he will die. Is it permissible to unplug yourself? Thomson thinks the answer is ‘yes’. And this, she thinks, shows that abortion is permissible even if the fetus is a person. While the majority of her article focuses on the ethics of abortion, it is clear that she also aims to show that abortion should be legal if the fetus is a person; she would no doubt reject the view that the state is right to coerce you into …. (shrink)

In cases in which we must choose between either (i) preventing a woman from remaining unwillingly pregnant or (ii) preventing a fetus from being killed, we should prevent the fetus from being killed. But this suggests that in typical cases abortion is wrong: typical abortions involve preventing a woman from remaining unwillingly pregnant over preventing a fetus from being killed. And so abortion is typically wrong—and this holds whether or not fetuses are persons.

Demonstratives seem to have posed a severe difficulty for Frege’s philosophy of language, to which his doctrine of incommunicable senses was a reaction. In “The Thought,” Frege briefly discusses sentences containing such demonstratives as “today,” “here,” and “yesterday,” and then turns to certain questions that he says are raised by the occurrence of “I” in sentences (T, 24-26). He is led to say that, when one thinks about oneself, one grasps thoughts that others cannot grasp, that cannot be communicated. However, (...) nothing could be more out of the spirit of Frege’s account of sense and thought than an incommunicable, private thought. In the first part of the paper, I explain the problem demonstratives pose for Frege, and explore three ways he might have dealt with it. I argue that none of these ways provides Frege with a solution to his problem consistent with his philosophy of language. The first two are plausible as solutions, but contradict his identification of the sense expressed by a sentence with a thought. The third preserves the identification, but is implausible. In the second part, I suggest that Frege was led to his doctrine of incommunicable senses as a result of some appreciation of the difficulties his account of demonstratives faces, for these come quickly to the surface when we think about “I.” I argue that incommunicable senses won’t help. I end by trying to identify the central problem with Frege’s approach, and sketching an alternative. (shrink)

This article is a response to Stephen Law's article ‘The evil-god challenge’. In his article, Law argues that if belief in evil-god is unreasonable, then belief in good-god is unreasonable; that the antecedent is true; and hence so is the consequent. In this article, I show that Law's affirmation of the antecedent is predicated on the problem of good (i.e. the problem of whether an all-evil, all-powerful, and all-knowing God would allow there to be as much good in the world (...) as there is), and argue that the problem of good fails. Thus, the antecedent is unmotivated, which renders the consequent unmotivated. Law's challenge for good-god theists is to show that good-god theism is not rendered unreasonable by the problem of evil in the same way that evil-god theism is rendered unreasonable by the problem of good. Insofar as the problem of good does not render belief in evil-god unreasonable, Law's challenge has been answered: since it is not unreasonable to believe in evil-god (at least for the reasons that Law gives) it is not unreasonable to believe in good-god. Finally, I show that – my criticism aside – the evil-god challenge turns out to be more complicated and controversial than it initially appears, for it relies on the (previously unacknowledged) contentious assumption that sceptical theism is false. (shrink)

I provide an updated version of The Impairment Argument against abortion and respond to numerous objections that can be (and have been) raised to it.

Skeptical theism is a popular response to arguments from evil. Many hold that it undermines a key inference often used by such arguments. However, the case for skeptical theism is often kept at an intuitive level: no one has offered an explicit argument for the truth of skeptical theism. In this article, I aim to remedy this situation: I construct an explicit, rigorous argument for the truth of skeptical theism.

The pelvic exam is used to assess the health of female reproductive organs and so involves digital penetration by a physician. However, it is common practice for medical students to acquire experience in administering pelvic exams by performing them on unconscious patients without prior authorization. In this article, we argue that such unauthorized pelvic exams (UPEs) are sexual assault. Our argument is simple: in any other circumstance, unauthorized digital penetration amounts to sexual assault. Since there are no morally significant differences (...) between UPEs and other instances of digital penetration, UPEs are sexual assault. So, insofar as one is against sexual assault, one should be against UPEs. (shrink)

Critics of skeptical theism often claim that if it (skeptical theism) is true, then we are in the dark about whether (or for all we know) there is a morally justifying for God to radically deceive us. From here, it is argued that radical skepticism follows: if we are truly in the dark about whether there is a morally justifying reason for God to radically deceive us, then we cannot know anything. In this article, I show that skeptical theism does (...) not entail that we are in the dark about whether (or for all we know) there is a morally justifying reason for God to deceive us. And hence arguments against skeptical theism that make use of this assumption fail. (shrink)

Skeptical theism is a popular response to arguments from evil. Recently, Matthew A. Benton, John Hawthorne, and Yoaav Isaacs have argued that the theses that ground skeptical theism are either false or limited in scope. In this article, I show that their objections rest on dubious assumptions about the nature of skeptical theism. Along the way, I develop and clarify the ambiguous parts of skeptical theism. The upshot of this is that—once the nature of skeptical theism is made clearer—it is (...) far more difficult to resist. (shrink)

The “Embryo Rescue Case” (ERC) refers to a thought experiment that is used to argue against the view that embryos have a right to life (i.e. are persons). I will argue that cognitive science undermines the intuition elicited by the ERC; I will show that whether or not embryos have a right to life, our mental tools will make it very difficult to believe that embryos have said right. This suggests that the intuition elicited by the ERC is not truth (...) indicative. The upshot of this is that we have an undercutting defeater for our intuition that embryos do not have a right to life. (shrink)

This paper is a response to Tyler Wunder’s ‘The modality of theism and probabilistic natural theology: a tension in Alvin Plantinga's philosophy’ (this journal). In his article, Wunder argues that if the proponent of the Evolutionary Argument Against Naturalism (EAAN) holds theism to be non-contingent and frames the argument in terms of objective probability, that the EAAN is either unsound or theism is necessarily false. I argue that a modest revision of the EAAN renders Wunder’s objection irrelevant, and that this (...) revision actually widens the scope of the argument. (shrink)

Abortion restrictions are particularly good for black women—at least in the United States. This claim will likely strike many as outlandish. And numerous commentaries on abortion restrictions have suggested otherwise: many authors have lamented the effects of abortion restrictions on women, and black women in particular—these restrictions are bad for them, these authors say. However, abortion restrictions are clearly good for black women. This is because if someone is prevented from performing a morally wrong action, it’s good for her. For (...) example, it’s good for Sarah if she’s prevented from driving home drunk. However, since abortion is morally wrong, it follows that it’s good for women when they are prevented from getting an abortion. And since black women get abortions at disproportionately high rates, abortion restrictions are good in particular for black women. Indeed, this is an example of a positive effect of intersectionality. (shrink)

Trent Dougherty has argued that commonsense epistemology and skeptical theism are incompatible. In this paper, I explicate Dougherty’s argument, and show that (at least) one popular form of skeptical theism is compatible with commonsense epistemology.

De facto objections to theism purport to show that theism is false, whereas de jure objections to theism claim that, whether or not theism is true, belief in God is irrational. Divine hiddenness – the fact that there are people who non-resistantly lack belief in God – is sometimes used as an argument against theism. In this article I will show that accepting the argument from divine hiddenness carries a high cost: it eliminates all de jure objections to theism. So (...) atheists can either have de jure objections to theism or the objection from divine hiddenness, but they cannot have both. (shrink)

Perry Hendricks’ original impairment argument for the immorality of abortion is based on the impairment principle (TIP): if impairing an organism to some degree is immoral, then ceteris paribus, impairing it to a higher degree is also immoral. Since abortion impairs a fetus to a higher degree than fetal alcohol syndrome (FAS) and giving a fetus FAS is immoral, it follows that abortion is immoral. Critics have argued that the ceteris paribus is not met for FAS and abortion, and (...) so we proposed the Modified Impairment Principle (MIP) to avoid these difficulties. Dustin Crummett has responded, arguing that MIP is open to various counterexamples which show it to be false. He also shows that MIP can generate moral dilemmas. Here, we propose a modification to MIP that resolves the issues Crummett raises. Additionally, Alex Gillham has criticized our appropriation of Don Marquis’ ‘future like ours’ reasoning about the wrongness of impairment. We show that his objections have minimal implications for our argument. (shrink)

Perry Hendricks’ impairment argument for the immorality of abortion is based on two premises: first, impairing a fetus with fetal alcohol syndrome is immoral, and second, if impairing an organism to some degree is immoral, then ceteris paribus, impairing it to a higher degree is also immoral. He calls this the impairment principle. Since abortion impairs a fetus to a higher degree than FAS, it follows from these two premises that abortion is immoral. Critics have focussed on the ceteris (...) paribus clause of TIP, which requires that the relevant details surrounding each impairment be sufficiently similar. In this article, we show that the ceteris paribus clause is superfluous, and by replacing it with a more restrictive condition, the impairment argument is considerably strengthened. There are no data in this work. (shrink)

Lougheed argues that a possible solution to the problem of divine hiddenness is that God hides in order to increase the axiological value of the world. In a world where God exists, the goods associated with theism necessarily obtain. But Lougheed also claims that in such a world it’s possible to experience the goods of atheism, even if they don’t actually obtain. This is what makes a world with a hidden God more valuable than a world where God is unhidden, (...) and also more valuable than an atheistic world with no God. We show that Lougheed never considers the comparison between a world where God hides and an atheistic world. We argue that it’s possible for a person to experience theistic goods in a world where God does not exist, a possibility Lougheed never considers. If this is right it undermines his axiological solution to divine hiddenness. We conclude by showing how our discussion of the axiology of theism connects to the existential question of whether God exists; that is, we show that the axiological question is dependent on the existential question. (shrink)

In this paper, I consider Sterba’s recent criticism of skeptical theism in context of his argument from evil. I show that Sterba’s criticism of skeptical theism shares an undesirable trait with all past criticisms of skeptical theism: it fails. This is largely due to his focus on causal connections and his neglect of logical connections. Because of this, his argument remains vulnerable to skeptical theism.

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.

This article motivates and develops a reductive account of the structure of certain physical quantities in terms of their mereology. That is, I argue that quantitative relations like "longer than" or "3.6-times the volume of" can be analyzed in terms of necessary constraints those quantities put on the mereological structure of their instances. The resulting account, I argue, is able to capture the intuition that these quantitative relations are intrinsic to the physical systems they’re called upon to describe and explain.

Although better known for his phenomenology of perception and the perceived world, Merleau-Ponty’s writings also contain the outlines of a rich and unique account of the imagination and the imaginary. In this paper, I explicate the phenomenology of the image that Merleau-Ponty develops throughout his work. I show how Merleau-Ponty develops this account of the image in critical response to Sartre and in a way that follows from his own descriptions of what painters do when they paint and of what (...) we experience when we look at their paintings. The investigation of the particular mode of being of images leads to a consideration of the body and Merleau-Ponty’s later ontology. (shrink)

One of HLA Hart's main contributions to jurisprudence is his theory of social rules. Hart said, essentially, that a social rule exists if the members of a society act in some way and have a certain attitude. Most legal philosophers think that Hart's account of this attitude is too general, however, and that his theory is overinclusive as a result. In this article, I draw on recent work in the philosophy of action to propose a more precise account of the (...) relevant attitude, and a revised version of Hart's theory. I claim that a social rule exists if the members of a society act in some way and ‘accept’ they ought to act this way, independent of their beliefs about the matter. One of the implications of this idea is that the attitude that underlies a social rule is closely analogous to a presumption or fiction about what ought to be done. -/- . (shrink)

An ongoing challenge within all approaches to ethical decision making is reducing the degree of doubt about what action is right, good, or at least better in a given situation. The process of moral discernment within Christian thought is no exception; however, different Christian communities tend to understand moral doubt and moral certainty differently, to pursue different ways of allaying doubt, and to expect—and accept—different degrees of moral certainty. Drawing especially from Aristotelian virtue theory, selected teachings from the Eastern Orthodox (...) tradition on humility, and recent discussions of the ‘grace of self-doubt,’ I sketch an account of virtuous moral doubt as a mean between the extremes of excessive and deficient moral doubt. My hope is doing so will help to make space and provide the framework for an ecumenical understanding of doubt’s proper role in moral discernment. (shrink)

The subject’s perspective objection (SPO) is an objection against externalist theories of justification, warrant, and knowledge. In this article, I show that externalists can accommodate the SPO while remaining externalist. So, even if the SPO is successful, it does not motivate internalism, and the primary motivation for internalism has been lost. After this, I provide an explanation for why so many people find cases that motivate the SPO convincing.

The ethics of abortion considers whether abortion is immoral. Pro-choice philosophers think that it is not immoral, while pro-life philosophers think that it is. The axiology of abortion considers whether world would be better if the pro-choice or pro-life position is right. While much attention has been given to the ethics of abortion, there has been no attention given to the axiology of abortion. In this article, I seek to change that. I consider various arguments for thinking our world would (...) be better if the pro-choice position or the pro-life position is correct, ultimately concluding that it would be better if the pro-choice position is right. This is unfortunate, however, since there is no good reason to think the pro-choice position is correct. (shrink)

Tim Maudlin has influentially argued that Humeanism about laws of nature stands in conflict with quantum mechanics. Specifically Humeanism implies the principle Separability: the complete physical state of a world is determined by the intrinsic physical state of each space-time point. Maudlin argues Separability is violated by the entangled states posited by QM. We argue that Maudlin only establishes that a stronger principle, which we call Strong Separability, is in tension with QM. Separability is not in tension with QM. Moreover, (...) while the Humean requires Separability to capture the core tenets of her view, there's no Humean-specific motivation for accepting Strong Separability. We go on to give a Humean account of entangled states which satisfies Separability. The core idea is that certain quantum states depend upon the Humean mosaic in much the same way as the laws do. In fact, we offer a variant of the Best System account on which the systemization procedure that generates the laws also serves to ground these states. We show how this account works by applying it to the example of Bohmian Mechanics. The 3N-dimensional configuration space, the world particle in it and the wave function on it are part of the best system of the Humean mosaic, which consists of N particles moving in 3-dimensional space. We argue that this account is superior to the Humean account of Bohmian Mechanics defended by Loewer and Albert, which takes the 3N-dimensional space, and its inhabitants, as fundamental. (shrink)

I’ve argued that those who endorse the argument from divine hiddenness must give up all pure de jure objections to theism, and this means that endorsing the argument is costly for atheists. Benjamin Curtis claims that this isn’t a significant cost for atheists. I show that—contrary to Curtis—there is a significant cost, and spell out why this is so. Furthermore, I show that my argument functions as a new argument for affirming reformed epistemology—the view that if theism is true, belief (...) in God is probably rational. (shrink)

Legal discourse consists largely of legal claims. These are claims that there is a legal obligation, legal right, or other legal incident. What is the meaning of “legal obligation”, “legal right” and so on in legal claims? The standard view among philosophers of law is that “legal” indicates that, according to law, there is a moral obligation, moral right or other moral incident. Here I set out a new objection to the standard view. The objection is that the standard view (...) is unable to account for the use of legal claims in some common forms of logically complex arguments. (shrink)

P-zombies are creatures that are physically (functionally, behaviorally) like you and I and yet lack phenomenal consciousness. If such creatures are possible, it’s (typically) taken to show property dualism is true: phenomenal consciousness isn’t reducible to—nor does it supervene on—physical states. If inverted qualia are possible, it’s possible that you and I have identical physical states and yet you see tomatoes as green and I see tomatoes as red. If this is the case, then (again) property dualism is (typically) taken (...) to be true. In this article, I’ll show that p-zombies and inverted qualia—if they are actually possible—prove more than previously thought: if one thinks p-zombies or inverted qualia are possible, then she should endorse one of the four following theses: (i) substance dualism, (ii) we have even more reason to reject p-zombies and inverted qualia since they entail an even more radical conclusion than previously thought (i.e. substance dualism), (iii) eliminativism about selves, or (iv) friends of p-zombies and inverted qualia have homework: they need to show a relevant, plausible disanalogy between arguments for p-zombies and inverted qualia as traditionally stated and my parallel arguments that entail substance dualism. My purpose here isn’t to defend any of these particular options. Instead, my purpose is to highlight that these are the four options available to take. (shrink)

In this article, I argue that sceptical theists have too narrow a focus: they consider only God’s axiological reasons, ignoring any non-axiological reasons he may have. But this is a mistake: predicting how God will act requires knowing about his reasons in general, and this requires knowing about both God’s axiological and non-axiological reasons. In light of this, I construct and defend a kind of sceptical theism—Deontological Sceptical Theism—that encompasses all of God’s reasons, and briefly illustrate how it renders irrelevant (...) certain charges of excessive sceptical and how it evaporates equiprobability objections. Furthermore, I put forth a simple argument in favor of Deontological Sceptical Theism, which shows that everyone (at least currently) ought to endorse it. (shrink)

(Wide) pro-theism is the view that the world is better overall if theism is true. (Wide) anti-theism is the view that our world would be better overall if atheism is true. Arguments for pro-theism and anti-theism typically make use of traditional theism (the view that an omni-God exists) and generic atheism (the view that an omni-God doesn’t exist). In my view, when the debate between pro-theists and anti-theists makes use of traditional theism and generic atheism, pro-theism clearly comes out on (...) top. In this paper, I consider whether this result (i.e. pro-theism’s advantage over anti-theism) changes if we bring axiarchism into the mix: I compare axiarchistic theism and axiarchistic atheism. General axiarchism is the view that the world exists because it is good that it exists, and extreme axiarchism is the view that the world exists because it is the best possible world. When we take general axiarchistic theism and general axiarchistic atheism as our worldviews for comparison, I argue that there is no significant change with respect to anti-theism and pro-theism: neither position is able to capture goods that are traditionally associated with the other position, and so pro-theism still wins out. However, if we instead compare extreme axiarchistic atheism with extreme axiarchistic theism there is a significant change: while the case for pro-theism remains the same (because, I argue, it is not able to capture any of the goods of anti-theism), the case for anti-theism is greatly strengthened, because it is able to capture nearly all of the goods of pro-theism (e.g. the good of an afterlife, of cosmic justice, of there being no gratuitous evil). In other words, given extreme axiarchism, atheistic worlds can (and will) house goods that are traditionally associated with theistic worlds (e.g. those listed prior). This means that, given extreme axiarchism, pro-theists can’t appeal to those goods as favoring their position: they obtain whether our world is atheistic or theistic. Thus, they don’t favor pro-theism over anti-theism; the case for anti-theism has been strengthened. (Alternatively, we may say that the case for pro-theism has been weakened.) Ultimately, there is one good that extreme axiarchistic atheism does not enable anti-theism to capture—namely, God’s intrinsic unlimited goodness—and I argue that this shows that there is still a gap between pro-theism and anti-theism; while the gap has been substantially narrowed, it has not been eliminated. Thus, I suggest that the best route forward for anti-theists is to cast doubt on the view that God’s intrinsic goodness is unlimited. (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)

Tiddy Smith argues that common consent amongst geographically and historically isolated communities provides strong evidence for animism―the view that there are nature spirits. In this article, I argue that the problem of animistic hiddenness―the lack of widespread belief in nature spirits―is at least as strong evidence against animism that common consent is evidence for it, meaning that the evidence for animism that Smith provides is neutralized.

The evil-god challenge is a challenge for theists to show that belief in God is more reasonable than belief in evil-god. In this article, I show that whether or not evil-god exists, belief in evil-god is unjustified. But this isn’t the case for belief in God: belief in God is probably justified if theism is true. And hence belief in God is (significantly) more reasonable than belief in evil-god, and the evil-god challenge has been answered.

In this chapter, I consider personal and impersonal anti-theism and personal and impersonal pro-theism. I show that skeptical theism undermines arguments for personal anti-theism and impersonal anti-theism. Next, I show that (at least some) arguments for personal and impersonal pro-theism are not undermined by skeptical theism. This throws a wrench in debates about the axiology of theism: if skeptical theism is true, then it is very difficult to establish certain positions in answer to the axiological question about God.

Self, person, and identity are among the concepts most central to the way humans think about themselves and others. It is often natural in biology to use such concepts; it seems sensible to say, for example, that the job of the immune system is to attack the non-self, but sometimes it attacks the self. But does it make sense to borrow these concepts? Don’t they only pertain to persons, beings with sophisticated minds, and perhaps even souls? I argue that if (...) we focus on the every-day concepts of self and identity, and set aside loftier concepts found in religion, philosophy, and psychology that are applicable, at most, to humans, we can see that self and identity can be sensibly applied widely in biology. (shrink)

Bergson identifies multiple forms of memory throughout his work. In Matter and Memory, Bergson considers memory from the perspectives of both psychology and metaphysics, and he describes what we might refer to as contraction memory, perception memory, habit memory, recollection memory, and pure memory. Further, in subsequent works, Bergson discusses at least two additional forms of memory – namely, a memory of the present and a non-intellectual memory of the will. However, it is often not clear how these different forms (...) of memory relate to one another. With the aim of providing an overview of Bergson's philosophy of memory that can also serve as a point of entry to his philosophy as a whole, this article explores the different senses and forms of memory that Bergson describes, paying special attention to how they are distinct from one another and how they are unified. It is my intention to show that, although these various senses and forms of memory are different from one another , they are also continuous and unified insofar as they are equivalent to different tones of one's mental life and to different tensions of one duration. (shrink)

The norms of a legal system are relevant in deciding on people's rights and duties within that system. Some norms that are not part of a legal system are also relevant within it: norms of foreign legal systems, games, clubs, contracts, grammar, and so on. What distinguishes the norms of a legal system from the norms merely relevant within it? Where, in other words, are law's boundaries? There are three existing answers in the literature, from Kramer, Shapiro, and Raz. None (...) succeed. A better answer starts with a distinction between two types of legal relevance: direct and indirect. Norms of a legal system are directly relevant within it. Norms that are not part of a legal system are at most indirectly relevant within it. Thus, the two types of norms are distinguished by the directness of their relevance. (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)

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 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)