We present a quantitative model of sex allocation to investigate whether the simple “rules of thumb” suggested by Trivers and Willard (1973) would really maximize numbers of grandchildren in human populations. Using demographic data from the !Kung of southern Africa and the basic assumptions of the Trivers-Willard hypothesis, we calculate expected numbers of grandchildren based on age- and sex-specific reproductive value. Patterns of parental investment that would maximize numbers of expected grandchildren often differ from the (...) class='Hi'>Trivers-Willard rules. In particular, the optimum parental behavior is sensitive to population dynamics, type of parental investment, and, most important, relative ages of sons and daughters. It is doubtful whether a parent blindly following the simple Trivers-Willard rules would maximize numbers of expected grandchildren, on average. In addition, we show that sex-specific infanticide will almost never achieve the goal of maximizing expected numbers of grandchildren. (shrink)

Can mammalian mothers adaptively control the sex of their offspring? The influential Trivers-Willard hypothesis proposes that when maternal condition increases the fitness of sons more than that of daughters, the proportion of sons produced should increase with maternal condition. Studies of mammals, however, often fail to support this hypothesis. This article highlights recent advances, including studies on the assumptions of the TWH and physiological mechanisms for sex-ratio manipulation. Particular emphasis is placed on how factors such as paternal quality, (...) maternal reproductive costs and environmental conditions experienced by mothers early in life can mask/alter the expected relationship between maternal condition and offspring sex ratio or lead to apparent support for the TWH. While there is growing evidence that sex ratio around conception may be maternally and paternally manipulated, a challenge for future studies on sex allocation is to integrate how multiple and potentially opposite selective pressures affect offspring sex ratio. The relationship between offspring sex and maternal condition lies at the heart of one of the most controversial hypotheses in evolutionary biology. This review highlights recent findings on the Trivers-Willard hypothesis with particular emphasis on factors which may mask the relationship of interest or falsely demonstrate it. (shrink)

Female-biased parental investment is unusual but not unknown in human societies. Relevant explanatory models include Fisher’s principle, the Trivers-Willard model, local mate and resource competition and enhancement, and economic rational actor models. Possible evidence of female-biased parental investment includes sex ratios, mortality rates, parents’ stated preferences for offspring of one sex, and direct and indirect measurements of actual parental behavior. Possible examples of female-biased parental investment include the Mukogodo of Kenya, the Ifalukese of Micronesia, the Cheyenne of North (...) America, the Herero of southern Africa, the Kanjar of south Asia, the Mundugumor of New Guinea, contemporary North America, and historical Germany, Portugal, and the United States. (shrink)

If parenting behavior influences attachment, then parental investment (PI) theory can predict sex differences and distributions of attachment styles across cultures. Trivers-Willard, local resource competition, and local resource enhancement models make distinct predictions for sex-biased parental responsiveness relevant to attachment. Parental investment and attachment probably vary across cultures in relation to for status, wealth, and well-being.

Data from the Kipsigis of Kenya are used to test two models for how parents invest in offspring, the Trivers-Willard and local resource competition/enhancement hypotheses. Investment is measured as age-specific survival, educational success, marital arrangements, and some components of property inheritance, permitting an evaluation of how biases persist or alter over the period of dependence. Changes through time in such biases are also examined. Despite stronger effects of wealth on the reproductive success of men than women, the survival (...) of sons and daughters is not related to parental wealth. However, a Trivers-Willard effect characterizes educational investment: poor families show a greater concern for daughters’ (vis-à-vis sons’) schooling than do rich families, a trend that has increased over time. In regard to models of local resource competition and enhancement, men’s reproductive success decreases with number of brothers and increases with number of sisters; this pattern of competition with same-sex sibs and cooperation with opposite-sex sibs is not found among women. As predicted from these observations, parents show reduced investment in sons with a large number of brothers, and increased investment in sons with a large number of sisters. By contrast, investment in daughters is entirely unaffected by number of sisters and is influenced only in subtle ways by number of brothers. Levels of investment in relation to sibship size (irrespective of siblings’ sex) are highest for younger children of large sib sets.Discussion of the results in relation to those from other studies leads to three conclusions. First, predictive models for how investment biases vary across societies must consider a broad range of socioecological factors constraining parental options and payoffs. Second, the timing of investment biases within societies will be affected by the value of children and the costs of parental investment. Third, measures of investment appropriate for between-sex and between-class comparisons need careful attention. Each of these issues is brought to bear on the question of why, in contrast to so many other parts of the world, sex preferences are so muted in Africa. (shrink)

Combined with recent evolutionary psychological theories, Crespi & Badcock's (C&B's) intragenomic conflict theory of the social brain suggests that schizophrenics are more religious, and autistics are less religious, than the normal population. Combined with the generalized Trivers-Willard hypothesis (gTWH), it suggests that schizophrenics have more daughters, and autistics have more sons, than expected.

This study examines child survival and growth in a patrilineal Ethiopian community as a function of father absence and sex. In line with evolutionary predictions for sex-biased parental investment, the absence of a father and associated constraints on household resources is more detrimental for sons’ than daughters’ survival in infancy. Father absence doubles a son’s risk of dying in infancy but has a positive influence on the well-being of female members of the household, improving daughter survival, growth, and maternal nutritional (...) status. Lack of paternal investment may be compensated for by other matrilateral kin through increased reciprocity between mother, daughter, and sister. (shrink)

Growing evidence suggests mothers invest more in girls than boys and fathers more in boys than girls. We develop a hypothesis that predicts preference for girls by the parent facing more resource constraints and preference for boys by the parent facing less constraint. We test the hypothesis with panel data from the Tsimane’, a foraging-farming society in the Bolivian Amazon. Tsimane’ mothers face more resource constraints than fathers. As predicted, mother’s wealth protected girl’s BMI, but father’s wealth had weak effects (...) on boy’s BMI. Numerous tests yielded robust results, including those that controlled for fixed effects of child and household. (shrink)

Independent samples of women were surveyed to test Trivers and Willard’s hypothesis that the mother’s condition and her ability to invest in her offspring affect the (secondary) sex ratio of her offspring. Patterns of sex ratios (number of males per 100 females) were analyzed in conjunction with four attributes of a mother’s microenvironment: level of health in her community, family structure, relative access to resources, and her birthing history. The results inferentially support the hypothesis that the microenvironment of (...) the woman would act to bias the sex ratio of her offspring. These specific data lend support to Trivers and Willard’s general hypothesis. (shrink)

La Logique elementaire est a la fois une introduction a la logique et une introduction a la pensee de Quine, son but ayant ete de condenser le sujet de la logique traditionnelle en le traitant par les moyens de la logique contemporaine, afin de rendre plus intelligibles les constructions logiques de base et les raisonnements impliques dans le langage usuel. Le lecteur trouvera ici tous les elements necessaires a la comprehension du symbolisme logique, mais aussi et surtout le role de (...) la logique formelle comme instrument d'analyse du langage usuel. (shrink)

This volume consists of the first of the John Dewey Lectures delivered under the auspices of Columbia University's Philosophy Department as well as other essays by the author. Intended to clarify the meaning of the philosophical doctrines propounded by Professor Quine in 'Word and Objects', the essays included herein both support and expand those doctrines.

Willard Van Orman Quine begins this influential work by declaring, "Language is asocial art.

The #metoo movement has forced many fans to consider what they should do when they learn that a beloved artist has acted immorally. One natural thought is that fans ought to give up the artworks of immoral artists. In Why It's OK to Enjoy the Work of Immoral Artists, Mary Beth Willard argues for a more nuanced view. Enjoying art is part of a well-lived life, so we need good reasons to give it up. And it turns out good (...) reasons are hard to find. Willard show that it's reasonable to believe that most boycotts of artists won't succeed, so most of the time there's no ethical reason to join in. Someone who manages to separate the art from the artist isn't making an ethical mistake by buying and enjoying their art. She then considers the ethical dimensions of canceling artists and so-called "cancel culture," arguing that canceling is ethically risky because it encourages moral grandstanding. Willard concludes by arguing that the popular debate has overlooked the power of art to change our lives for the good. It's of course OK to decide to give up the artwork of immoral artists, but--as Willard shows in this provocative little volume--it's OK to continue to enjoy their art, as well. Key Features Offers accessible discussions of complicated philosophical topics like aesthetic value, collective action problems, and epistemic justice Provides a unique perspective and underexplored argument on the popular issue of cancellation Explores the role of aesthetic value in our lives, including its relation to our ethical decisions and our well being. (shrink)

Several of these essays have been printed whole in journals; others are in varying degrees new. Two main themes run through them. One is the problem of meaning, particularly as involved in the notion of an analytic statement. The other is the notion of ontological, commitment, particularly as involved in the problem of universals.

Modern empiricism has been conditioned in large part by two dogmas. One is a belief in some fundamental cleavage between truths which are analytic, or grounded in meanings independently of matters of fact, and truth which are synthetic, or grounded in fact. The other dogma is reductionism: the belief that each meaningful statement is equivalent to some logical construct upon terms which refer to immediate experience. Both dogmas, I shall argue, are ill founded. One effect of abandoning them is, as (...) we shall see, a blurring of the supposed boundary between speculative metaphysics and natural science. Another effect is a shift toward pragmatism. (shrink)

A respected Harvard logician and philosopher gathers together twenty-nine writings dealing with the foundations of mathematics, Rudolf Carnap, lin-guistics, ...

A compact, coherent introduction to the study of rational belief, this text provides points of entry to such areas of philosophy as theory of knowledge, methodology of science, and philosophy of language. The book is accessible to all undergraduates and presupposes no philosophical training.

Kant's question 'How are synthetic judgments a priori possible?' pre- cipitated the Critique of Pure Reason. Question and answer notwith- standing, Mill and others persisted in doubting that such judgments were possible at all. At length some of Kant's own clearest purported.

Erich Hatala Matthes’s (2021)Drawing the Line is about what we ought to do when we discover that an artist whom we love has committed a great moral wrong. As it turns out, Matthes and I agree almost entirely on the moral obligations of the individual consumer. We both agree that it is necessary to ascertain whether the life of the artist affects the aesthetic quality of their work, and that we should attend to how continuing to engage with their work (...) publicly expresses our ethical values. Both of us wind up with a morally permissive stance, according to which individuals can, in some contexts, continue to engage with the artwork of immoral artists.There is one distinct difference in how we approached the problem. Matthes took up the question of the role and responsibility of institutions in his third chapter, a question I set aside almost entirely. In this article, I want to delve more deeply into the question of art institutions and their responsibilities to reform themselves. I will argue that the nature of aesthetic practice means that it is harder for an institution to tread the desirable middle ground between uncritically endorsing an immoral artist and cancelling them. (shrink)

" This is a key book for understanding the effort that a major philosopher has made a large part of his life's work: to naturalize epistemology in the twentieth ...

Provides comprehensive coverage of logical structure as well as the techniques of formal reasoning.

Quine's areas of interest are panoramic, as this lively book amply demonstrates.

A growing number of epistemologists have endorsed the Ignorance Norm for Inquiry. Roughly, this norm says that one should not inquire into a question unless one is ignorant of its answer. I argue that, in addition to ignorance, proper inquiry requires a certain kind of knowledge. Roughly, one should not inquire into a question unless one knows it has a true answer. I call this the Knowledge Norm for Inquiry. Proper inquiry walks a fine line, holding knowledge that there is (...) an answer in the left hand and ignorance of the answer in the right. (shrink)

For the faithful there is much to ponder. In this short book, based on lectures delivered in Spain in 1990, Quine begins by locating his work historically.

Suppose now that two philosophers, McX and I, differ over ontology. Suppose McX maintains there is something which I maintain there is not. McX can, quite consistently with his own point of view, describe our difference of opinion by saying that I refuse to recognize certain entities. I should protest of course that he is wrong in his formulation of our disagreement, for I maintain that there are no entities, of the kind which he alleges, for me to recognize; but (...) my finding him wrong in his formulation of our disagreement is unimportant, for I am committed to considering him wrong in his ontology anyway. When I try to formulate our difference of opinion, on the other hand, I seem to be in a predicament. I cannot admit that there are some things which McX countenances and I do not, for in admitting that there are such things I should be contradicting my own rejection of them. (shrink)

Unlike first-person Moorean sentences, it’s not always awkward to assert, “p, but you don’t know that p.” This can seem puzzling: after all, one can never get one’s audience to know the asserted content by speaking thus. Nevertheless, such assertions can be conversationally useful, for instance, by helping speaker and addressee agree on where to disagree. I will argue that such assertions also make trouble for the growing family of views about the norm of assertion that what licenses proper assertion (...) is not the initiating epistemic position of the speaker but the resulting epistemic position of the audience. (shrink)

With his customary incisiveness, W. V. Quine presents logic as the product of two factors, truth and grammar-but argues against the doctrine that the logical truths are true because of grammar or language. Rather, in presenting a general theory of grammar and discussing the boundaries and possible extensions of logic, Quine argues that logic is not a mere matter of words.

W. V. Quine’s systematic development of mathematical logic has been widely praised for the new material presented and for the clarity of its exposition. This revised edition, in which the minor inconsistencies observed since its first publication have been eliminated, will be welcomed by all students and teachers in mathematics and philosophy who are seriously concerned with modern logic. Max Black, in Mind, has said of this book, “It will serve the purpose of inculcating, by precept and example, standards of (...) clarity and precision which are, even in formal logic, more often pursued than achieved.”. (shrink)