Elliott Sober

Alexander Rosenberg began his recent article on the concept of fitness with the remark that “debates about the cognitive status of the Darwinian theory of natural selection should have ended long ago.” I agree that this obsession need to be overcome. But Rosenberg repeats some of the old mistakes and invents epicycles on others. In this comment I will not be able to circumscribe fully the range of the topics that an adequate treatment of this cluster of problems demands. A few critical comments will indicate what I find wanting in Rosenberg’s treatment.

The reception so far of Kitcher's Vaulting Ambition reminds me of the old saw about the difference between an optimist and a pessimist. Looking at the same glass of water, the former sees it as half full while the latter sees it as half empty. Some have seen Kitcher's book as a vindication of the possibility of an evolutionary science of human behavior; others have seen it as a devastating critique of the most influential efforts to date to construct such a science. As in the joke about the water glass, both assessments have their point. Sociobiology is a research program, not a unified theory. What one can do is test particular hypotheses within this program and see whether they live up to reasonable standards of rigor and evidence. This is what Kitcher does, with great energy and care.

Suppose that several observations “coincide,” meaning that they are similar in some interesting respect. Is this coinciding a mere coincidence, or does it derive from a common cause? Those who reason about this kind of question—whether they embrace the first answer or the second—often deploy a mode of inference that I call probabilistic modus tollens. In this chapter I criticize probabilistic modus tollens and consider likelihood and Bayesian frameworks for reasoning about coincidences. I also consider the perspective offered by model selection theory (including the Akaike information criterion), and argue that model selection often provides important insights.

Charles Stein discovered a paradox in 1955 that many statisticians think is of fundamental importance. Here we explore its philosophical implications. We outline the nature of Stein’s result and of subsequent work on shrinkage estimators; then we describe how these results are related to Bayesianism and to model selection criteria like AIC. We also discuss their bearing on scientific realism and instrumentalism. We argue that results concerning shrinkage estimators underwrite a surprising form of holistic pragmatism.

Evolutionary theory is awash with probabilities. For example, natural selection is said to occur when there is variation in fitness, and fitness is standardly decomposed into two components, viability and fertility, each of which is understood probabilistically. With respect to viability, a fertilized egg is said to have a certain chance of surviving to reproductive age; with respect to fertility, an adult is said to have an expected number of offspring.1 There is more to evolutionary theory than the theory of natural selection, and here too one finds probabilistic concepts aplenty. When there is no selection, the theory of neutral evolution says that a gene’s chance of eventually reaching fixation is 1/(2N), where N is the number of organisms in the generation of the diploid population to which the gene belongs. The evolutionary consequences of mutation are likewise conceptualized in terms of the probability per unit time a gene has of changing from one state to another. The examples just mentioned are all “forwarddirected” probabilities; they describe the probability of later events, conditional on earlier events. However, evolutionary theory also uses “backwards probabilities” that describe the probability of a cause conditional on its effects; for example, coalescence theory allows one to calculate the expected number of generations in the past that the genes in the present generation find their most recent common ancestor.

In this brief space I want to describe how Chomsky's analysis of "psychological reality" departs from what I think is a fairly standard construal of the idea. This familiar formulation arises from distinguishing between someone's following a rule and someone's acting in conformity with a rule. The former idea, but not the latter, involves the idea that the person has some mental representation of the rule that plays a certain causal role in determining behavior. Although there may be many grammatical rules to which a person's verbal behavior (ignoring slips of the tongue and other performance interferences) conforms, only some of those rules have psychological reality; these are the ones that are internalized in thought and play some appropriate causal role.

Egoism and altruism need not be characterized as single factor theories of motivation, according to which there is a single kind of preference that moves people to action. Rather, each asserts a claim of causal primacy—a claim as to which sort of preference is the more powerful influence on behavior. This paper shows that this idea of causal primacy can be clarified in a standard scientific way. This formulation explains why many observed behaviors fail to discriminate between the hypothesis that the agent is altruistic and the hypothesis that the agent is egoistic. A distinction between altruistic motivation and altruistic action is then drawn, from which it follows that it is an open question how often altruists behave altruistically

Markov models of evolution describe changes in the probability distribution of the trait values a population might exhibit. In consequence, they also describe how entropy and conditional entropy values evolve, and how the mutual information that characterizes the relation between an earlier and a later moment in a lineage’s history depends on how much time separates them. These models therefore provide an interesting perspective on questions that usually are considered in the foundations of physics—when and why does entropy increase and at what rates do changes in entropy take place? They also throw light on an important epistemological question: are there limits on what your observations of the present can tell you about the evolutionary past?

Instrumentalism is usually understood as a semantic thesis: scientific theories are neither true nor false, but are merely instruments for making predictions. Scientific realists are on firm ground when they reject this semantic claim. This paper focuses on epistemological rather than semantic instrumentalism. This form of instrumentalism claims that theories are to be judged by their ability to make accurate predictions, and that predictive accuracy is the only consideration that matters in the end. I consider how instrumentalism is related to a quite different proposal concerning how theories should be evaluated—scientific realism. Instrumentalism allows for the fact that a false model can get one closer to the truth than a true one.

[Elliott Sober] In 'Two Dogmas of Empiricism', Quine attacks the analytic/synthetic distinction and defends a doctrine that I call epistemological holism. Now, almost fifty years after the article's appearance, what are we to make of these ideas? I suggest that the philosophical naturalism that Quine did so much to promote should lead us to reject Quine's brief against the analytic/synthetic distinction; I also argue that Quine misunderstood Carnap's views on analyticity. As for epistemological holism, I claim that this thesis does not follow from the logical point that Duhem and Quine made about the role of auxiliary assumptions in hypothesis testing, and that the thesis should be rejected. \\\ [Peter Hylton] Section I of this essay discusses Quine's views about reference, contrasting them with those of Russell. For the latter, our language and thought succeed in being about the world because of our acquaintance with objects; the relation of reference-roughly, the relation between a name and its bearer-is thus fundamental. For Quine, by contrast, the fundamental relation by which our language comes to be about the world, and to have empirical content, is that between a sentence and stimulations of our sensory surfaces; reference, while important, is a derivative notion. Section II shows how this view of reference as derivative makes possible the notorious Quinean doctrine of ontological relativity. Section III raises the issue of realism. It argues that somewhat different notions of realism are in play for Quine and for Russell-for Russell, objects, and our knowledge of objects, play the fundamental role, while for quine objectivity and truth are fundamental, with ontology being derivative.

How should the concept of evidence be understood? And how does the concept of evidence apply to the controversy about creationism as well as to work in evolutionary biology about natural selection and common ancestry? In this rich and wide-ranging book, Elliott Sober investigates general questions about probability and evidence and shows how the answers he develops to those questions apply to the specifics of evolutionary biology. Drawing on a set of fascinating examples, he analyzes whether claims about intelligent design are untestable; whether they are discredited by the fact that many adaptations are imperfect; how evidence bears on whether present species trace back to common ancestors; how hypotheses about natural selection can be tested, and many other issues. His book will interest all readers who want to understand philosophical questions about evidence and evolution, as they arise both in Darwin's work and in contemporary biological research.

The debate over the relative importance of natural selection as compared to other forces affecting the evolution of organisms is a long-standing and central controversy in evolutionary biology. The theory of adaptationism argues that natural selection contains sufficient explanatory power in itself to account for all evolution. However, there are differing views about the efficiency of the adaptation model of explanation. If the adaptationism theory is applied, are energy and resources being used to their optimum? This book presents an up-to-date view of this controversy and reflects the dramatic changes in our understanding of evolution that have occurred in the last twenty years. The volume combines contributions from biologists and philosophers, and offers a systematic treatment of foundational, conceptual, and methodological issues surrounding the theory of adaptationism. The essays examine recent developments in topics such as phylogenetic analysis, the theory of optimality and ess models, and methods of testing models.

Perhaps because of it implications for our understanding of human nature, recent philosophy of biology has seen what might be the most dramatic work in the philosophies of the ”special” sciences. This drama has centered on evolutionary theory, and in the second edition of this textbook, Elliott Sober introduces the reader to the most important issues of these developments. With a rare combination of technical sophistication and clarity of expression, Sober engages both the higher level of theory and the direct implications for such controversial issues as creationism, teleology, nature versus nurture, and sociobiology. Above all, the reader will gain from this book a firm grasp of the structure of evolutionary theory, the evidence for it, and the scope of its explanatory significance.

Reductionism is often understood to include two theses: (1) every singular occurrence that the special sciences can explain also can be explained by physics; (2) every law in a higher-level science can be explained by physics. These claims are widely supposed to have been refuted by the multiple realizability argument, formulated by Putnam (1967, 1975) and Fodor (1968, 1975). The present paper criticizes the argument and identifies a reductionistic thesis that follows from one of the argument's premises

Philosophers frequently extract two lessons from Moliere's joke about the doctor who tried to explain why opium puts people to sleep by claiming that it has a dormative virtue. First, the principle I will call the equivalence thesis: attributions of dispositional properties are equivalent to certain associated subjunctive conditionals. The second is what I will call the reducibility thesis: for a dispositional concept to be nonproblematic, its “physical basis” must be found. In what follows, I will briefly describe three theoretical positions that have been defended in different areas of psychology. Each claims that a certain disposition does not exist, even though the associated subjunctive conditional is not called into question. Besides showing that the equivalence thesis is mistaken, these examples also illustrate how that doctrine in fact conflicts with the requirement of reducibility. Not that that demand can withstand criticism either; both the equivalence claim and the reducibility claim are mistaken.

One possible interpretation of the species concept is that specifies are natural kinds. Another species concept is that species are individuals whose parts are organisms. Philip Kitcher takes seriously both these ideas; he sees a role for the genealogical/historical conception and also for the one that is “purely qualitative”. I criticize his ideas here. I see the genealogical conception at work in biological discussion of species and it is presupposed by an active and inventive research program, but the natural kind concept is not. I also criticize Kitcher’s criticisms against Hull’s position that species are individuals, including Kitcher’s idea that species are sets of organisms, his explanations of why “all swans are white” isn’t law-like, his discussion of the example of multiple origination. Finally, I argue that given the current evolutionary developments, pluralism is the "null hypothesis" that we should attempt to refute.

In Chapter 12 of Warrant and Proper Function, Alvin Plantinga constructs two arguments against evolutionary naturalism, which he construes as a conjunction E&N .The hypothesis E says that “human cognitive faculties arose by way of the mechanisms to which contemporary evolutionary thought directs our attention (p.220).”1 With respect to proposition N , Plantinga (p. 270) says “it isn’t easy to say precisely what naturalism is,” but then adds that “crucial to metaphysical naturalism, of course, is the view that there is no such person as the God of traditional theism.” Plantinga tries to cast doubt on the conjunction E&N in two ways.His “preliminary argument” aims to show that the conjunction is probably false, given the fact (R) that our psychological mechanisms for forming beliefs about the world are generally reliable.His “main argument” aims to show that the conjunction E&N is self-defeating — if you believe E&N , then you should stop believing that conjunction.Plantinga further develops the main argument in his unpublished paper “Naturalism Defeated” (Plantinga 1994).We will try to show that both arguments contain serious errors

We have two main objections to Kerr and Godfrey-Smith's (2002) meticulous analysis. First, they misunderstand the position we took in Unto Others – we do not claim that individual-level statements about the evolution of altruism are always unexplanatory and always fail to capture causal relationships. Second, Kerr and Godfrey-Smith characterize the individual and the multi-level perspectives in terms of different sets of parameters. In particular, they do not allow the multi-level perspective to use the individual fitness parameters i and i. We don't see why the multi-level perspective prevents one from thinking in these terms. Kerr and Godfrey-Smith's argument that Uyenoyama and Feldman's (1980, 1992) definition of altruism belongs more to the individualist perspective than it does to the multi-level perspective is an artifact of their choice of parameters; the same point applies to their argument about the individualism inherent in the idea of Class I and Class II fitness structures.

constructive empiricism asserts that it is not for science to reach a verdict on whether a theory is true or false, if the theory is about unobservable entities; science's only interest here, says Van Fraassen, is to discover whether the theory is ‘empirically adequate’. However, if a theory is soley about observables, empirical adequacy and truth are said to ‘coincide’, here discovering the theory's truth value is an appropriate scientific goal. Constructive empiricism thus rests an epistemological thesis on a semantical distinction. This paper critically examines the notion of aboutness and its epistemological significance. * I am grateful to members of my philosophy of science seminar during Spring, 1983 for useful discussion and to the two anonymous referees of this journal for providing helpful suggestions. I also thank the University of Wisconsin, Madison Graduate School for support in the form of a Romnes Faculty Fellowship.

It is a challenge to explain how evolutionary altruism can evolve by the process of natural selection, since altruists in a group will be less fit than the selfish individuals in the same group who receive benefits but do not make donations of their own. Darwin proposed a theory of group selection to solve this puzzle. Very simply, even though altruists are less fit than selfish individuals within any single group, groups of altruists are more fit than groups of selfish individuals. If a population is subdivided into many groups that vary in their altruistic tendencies, altruism will be favored at the level of selection among groups even as it is being disfavored at the level of selection among individuals within groups. Darwin’s scenario became the basis for a theoretical framework called multilevel selection theory.