Imprecise probabilities are often modelled with representors, or sets of probability functions. In the recent literature, two ways of interpreting representors have emerged as especially prominent: vagueness interpretations, according to which each probability function in the set represents how the agent's beliefs would be if any vagueness were precisified away; and comparativist interpretations, according to which the set represents those comparative confidence relations that are common to all probability functions therein. I argue that these interpretations have some important limitations. I (...) also propose an alternative—the functional interpretation—according to which representors are best interpreted by reference to the roles they play in the theories that make use of them. (shrink)

According to comparativism, degrees of belief are reducible to a system of purely ordinal comparisons of relative confidence. (For example, being more confident that P than that Q, or being equally confident that P and that Q.) In this paper, I raise several general challenges for comparativism, relating to (i) its capacity to illuminate apparently meaningful claims regarding intervals and ratios of strengths of belief, (ii) its capacity to draw enough intuitively meaningful and theoretically relevant distinctions between doxastic states, and (...) (iii) its capacity to handle common instances of irrationality. (shrink)

According to the preference-centric approach to understanding partial belief, the connection between partial beliefs and preferences is key to understanding what partial beliefs are and how they’re measured. As Ramsey put it, the ‘degree of a belief is a causal property of it, which we can express vaguely as the extent to which we are prepared to act on it’ The Foundations of Mathematics and Other Logical Essays, Routledge, Oxon, pp 156–198, 1931). But this idea is not as popular as (...) it once was. Nowadays, the preference-centric approach is frequently dismissed out-of-hand as behaviouristic, unpalatably anti-realist, and/or prone to devastating counterexamples. Cases like Eriksson and Hájek’s :183–213, 2007) preferenceless Zen monk and Christensen’s :356–376, 2001) other roles argument have suggested to many that any account of partial belief that ties them too closely to preferences is irretrievably flawed. In this paper I provide a defence of preference-centric accounts of partial belief. (shrink)

The standard representation theorem for expected utility theory tells us that if a subject’s preferences conform to certain axioms, then she can be represented as maximising her expected utility given a particular set of credences and utilities—and, moreover, that having those credences and utilities is the only way that she could be maximising her expected utility. However, the kinds of agents these theorems seem apt to tell us anything about are highly idealised, being always probabilistically coherent with infinitely precise degrees (...) of belief and full knowledge of all a priori truths. Ordinary subjects do not look very rational when compared to the kinds of agents usually talked about in decision theory. In this paper, I will develop an expected utility representation theorem aimed at the representation of those who are neither probabilistically coherent, logically omniscient, nor expected utility maximisers across the board—that is, agents who are frequently irrational. The agents in question may be deductively fallible, have incoherent credences, limited representational capacities, and fail to maximise expected utility for all but a limited class of gambles. (shrink)

A review of some major topics of debate in normative decision theory from circa 2007 to 2019. Topics discussed include the ongoing debate between causal and evidential decision theory, decision instability, risk-weighted expected utility theory, decision-making with incomplete preferences, and decision-making with imprecise credences.

Comparativism is the view that comparative confidences (e.g., being more confident that P than that Q) are more fundamental than degrees of belief (e.g., believing that P with some strength x). In this paper, I outline the basis for a new, non-probabilistic version of comparativism inspired by a suggestion made by Frank Ramsey in `Probability and Partial Belief'. I show how, and to what extent, `Ramseyan comparativism' might be used to weaken the (unrealistically strong) probabilistic coherence conditions that comparativism traditionally (...) relies on. (shrink)

One response to the problem of logical omniscience in standard possible worlds models of belief is to extend the space of worlds so as to include impossible worlds. It is natural to think that essentially the same strategy can be applied to probabilistic models of partial belief, for which parallel problems also arise. In this paper, I note a difficulty with the inclusion of impossible worlds into probabilistic models. Under weak assumptions about the space of worlds, most of the propositions (...) which can be constructed from possible and impossible worlds are in an important sense inexpressible; leaving the probabilistic model committed to saying that agents in general have at least as many attitudes towards inexpressible propositions as they do towards expressible propositions. If it is reasonable to think that our attitudes are generally expressible, then a model with such commitments looks problematic. (shrink)

ABSTRACT According to comparativism, comparative confidence is more fundamental than absolute confidence. In two recent AJP papers, Stefánsson has argued that comparativism is capable of explaining interpersonal confidence comparisons. In this paper, I will argue that Stefansson’s proposed explanation is inadequate; that we have good reasons to think that comparativism cannot handle interpersonal comparisons; and that the best explanation of interpersonal comparisons requires thinking about confidence in a fundamentally different way than that which comparativists propose: specifically, we should think of (...) confidence as a dimensionless quantity. (shrink)

Possible worlds models of belief have difficulties accounting for unawareness, the inability to entertain (and hence believe) certain propositions. Accommodating unawareness is important for adequately modelling epistemic states, and representing the informational content to which agents have in principle access given their explicit beliefs. In this paper, I develop a model of explicit belief, awareness, and informational content, along with an sound and complete axiomatisation. I furthermore defend the model against the seminal impossibility result of Dekel, Lipman and Rustichini, according (...) to which three intuitive conditions preclude non-trivial unawareness on any possible worlds model of belief. (shrink)

This paper provides an exposition and defence of Lewis' theory of radical interpretation. The first part explains what Lewis' theory was; the second part explains what it wasn't, and in so doing addresses a number of common objections that arise as a result of widespread myths and misunderstandings about how Lewis' theory is supposed to work.

This paper begins with a puzzle regarding Lewis' theory of radical interpretation. On the one hand, Lewis convincingly argued that the facts about an agent's sensory evidence and choices will always underdetermine the facts about her beliefs and desires. On the other hand, we have several representation theorems—such as those of (Ramsey 1931) and (Savage 1954)—that are widely taken to show that if an agent's choices satisfy certain constraints, then those choices can suffice to determine her beliefs and desires. In (...) this paper, I will argue that Lewis' conclusion is correct: choices radically underdetermine beliefs and desires, and representation theorems provide us with no good reasons to think otherwise. Any tension with those theorems is merely apparent, and relates ultimately to the difference between how 'choices' are understood within Lewis' theory and the problematic way that they're represented in the context of the representation theorems. For the purposes of radical interpretation, representation theorems like Ramsey's and Savage's just aren't very relevant after all. (shrink)

I explain the shutdown problem: the problem of designing artificial agents that (1) shut down when a shutdown button is pressed, (2) don’t try to prevent or cause the pressing of the shutdown button, and (3) otherwise pursue goals competently. I prove three theorems that make the difficulty precise. These theorems show that agents satisfying some innocuous-seeming conditions will often try to prevent or cause the pressing of the shutdown button, even in cases where it’s costly to do so. And (...) patience trades off against shutdownability: the more patient an agent, the greater the costs that agent is willing to incur to manipulate the shutdown button. I end by noting that these theorems can guide our search for solutions. (shrink)

Person-affecting views in population ethics state that (in cases where all else is equal) we’re permitted but not required to create people who would enjoy good lives. In this paper, I present an argument against every possible variety of person-affecting view. The argument takes the form of a dilemma. Narrow person-affecting views must embrace at least one of three implausible verdicts in a case that I call ‘Expanded Non-Identity.’ Wide person-affecting views run into trouble in a case that I call (...) ‘Two-Shot Non-Identity.’ One plausible practical upshot of my argument is as follows: we individuals and our governments should be doing more to reduce the risk of human extinction this century. (shrink)

Joy of a certain kind has an important affective role in demonstrating the overcoming of nihilism for Nietzsche. In this chapter I explore how one might arrive at a point where they too can give voice to Zarathustra’s proclamation that “all joy wills eternity.” There are consistent references to eternity and infinitude in passages of Nietzsche’s discussing nihilism. This is most obviously borne out in Nietzsche scholarship with reference to discussions of eternal recurrence. But eternal recurrence does not have a (...) monopoly for denoting Nietzsche’s employment of the motifs of eternity and infinitude. Eternal recurrence and its affirmation, I argue, is only a kind of end point for a process of overcoming nihilism. -/- My concern here is the manner in which Nietzsche employs these motifs to track three different stages related to nihilism. The first stage demonstrates an affective response of initial disorientation, which aims to engender a realization by the “marketplace atheists” that humanity must undergo the phenomenon of nihilism. Th e second stage documents an active confrontation with this phenomenon, which in turn offers deeper, more terrifying yet also more positive consequences of this realization, ones proffering new forms of freedom. The third stage is the constructive use to which Nietzsche sets these motifs in the service of life-affirmation, of which eternal recurrence plays an integral part. I examine several important passages using these motifs in Nietzsche’s mature writings, particularly from The Gay Science and Thus Spoke Zarathustra, to claim that they inform a developmental process concerning the realization of nihilism and its overcoming. -/- I conclude by claiming that the motifs of eternity and infinitude’s employment at each of these three stages mirrors the substance of the “Three Metamorphoses of the Spirit” section in Thus Spoke Zarathustra. (shrink)

Many philosophers are attracted to a complaints-based theory of the procreation asymmetry, according to which creating a person with a bad life is wrong (all else equal) because that person can complain about your act, whereas declining to create a person who would have a good life is not wrong (all else equal) because that person never exists and so cannot complain about your act. In this paper, I present two problems for such theories: the problem of impairable-life acceptance and (...) an especially acute version of the problem of improvable-life avoidance. I explain how these problems afflict two recent complaints-based theories of the procreation asymmetry, from Joe Horton and Abelard Podgorski. (shrink)

According to Critical-Level Views in population axiology, an extra life improves a population only if that life’s welfare exceeds some fixed ‘critical level.’ An extra life at the critical level leaves the new population equally good as the original. According to Critical-Range Views, an extra life improves a population only if that life’s welfare exceeds some fixed ‘critical range.’ An extra life within the critical range leaves the new population incommensurable with the original. -/- In this paper, I sharpen some (...) old objections to these views and offer some new ones. Critical-Level Views cannot avoid certain Repugnant and Sadistic Conclusions. Critical-Range Views imply that lives featuring no good or bad components whatsoever can nevertheless swallow up and neutralise goodness or badness. Both classes of view entail that certain small changes in welfare correspond to worryingly large differences in contributive value. -/- I then offer a view that retains much of the appeal of Critical-Level and Critical-Range Views while avoiding the above pitfalls. On the Imprecise Exchange Rates View, the quantity of some good required to outweigh a given unit of some bad is imprecise. This imprecision is the source of incommensurability between lives and populations. (shrink)

Lexical views in population axiology can avoid the Repugnant Conclusion without violating Transitivity or Separability. However, they imply a dilemma: either some good life is better than any number of slightly worse lives, or else the ‘at least as good as’ relation on populations is radically incomplete. In this paper, I argue that Archimedean views face an analogous dilemma. I thus conclude that the lexical dilemma gives us little reason to prefer Archimedean views. Even if we give up on lexicality, (...) problems of the same kind remain. (shrink)

Arrhenius’s impossibility theorems purport to demonstrate that no population axiology can satisfy each of a small number of intuitively compelling adequacy conditions. However, it has recently been pointed out that each theorem depends on a dubious assumption: Finite Fine-Grainedness. This assumption states that there exists a finite sequence of slight welfare differences between any two welfare levels. Denying Finite Fine-Grainedness makes room for a lexical population axiology which satisfies all of the compelling adequacy conditions in each theorem. Therefore, Arrhenius’s theorems (...) fail to prove that there is no satisfactory population axiology. In this paper, I argue that Arrhenius’s theorems can be repurposed. Since all of our population-affecting actions have a non-zero probability of bringing about more than one distinct population, it is population prospect axiologies that are of practical relevance, and amended versions of Arrhenius’s theorems demonstrate that there is no satisfactory population prospect axiology. These impossibility theorems do not depend on Finite Fine-Grainedness, so lexical views do not escape them. (shrink)

[The version of this paper published by Oxford online in 2019 was not copy-edited and has some sense-obscuring typos. I have posted a corrected (but not the final published) version on this site. The version published in print in 2020 has these corrections.] Which is more fundamental, assertion or testimony? Should we understand assertion as basic, treating testimony as what you get when you add an interpersonal addressee? Or should we understand testimony as basic, treating mere assertion -- assertion without (...) testimony -- as what you get when you subtract that interpersonal relation? In this chapter, I’ll argue for the subtractive approach and for the more general thesis that its treatment of the interpersonal element in assertion makes understanding that interpersonal element the key to understanding how assertion expresses belief. My theory of belief-expression in assertion treats it as internalizing the transmission of belief in testimony. How we understand that internalizing move depends on how we conceptualize the interpersonal element in testimony. Since what I’ll call the Command Model does not give us the conceptual resources to make this move, we should adopt an alternative that I’ll call the Custodial Model, on which a testifier aims not to convince her addressee but to reason with him – to give him reasons to believe what she tells him grounded in her trustworthiness in thus attempting to influence him. The subtractive approach to assertion thus rests on a key distinction between the aims of reasoning and persuasion. (shrink)

Critical-set views avoid the Repugnant Conclusion by subtracting some constant from the welfare score of each life in a population. These views are thus sensitive to facts about biographical identity: identity between lives. In this paper, I argue that questions of biographical identity give us reason to reject critical-set views and embrace the total view. I end with a practical implication. If we shift our credences towards the total view, we should also shift our efforts towards ensuring that humanity survives (...) for the long term. (shrink)

I explain and motivate the shutdown problem: the problem of creating artificial agents that (1) shut down when a shutdown button is pressed, (2) don’t try to prevent or cause the pressing of the shutdown button, and (3) otherwise pursue goals competently. I then propose a solution: train agents to have incomplete preferences. Specifically, I propose that we train agents to lack a preference between every pair of different-length trajectories. I suggest a way to train such agents using reinforcement learning: (...) we give the agent lower reward for repeatedly choosing same-length trajectories. (shrink)

Act consequentialism states that an act is right if and only if the expected value of its outcome is at least as great as the expected value of any other act’s outcome. Two objections to this view are as follows. The first is that act consequentialism cannot account for our normative ambivalence in cases where agents perform the right act out of bad motives. The second is that act consequentialism is silent on questions of character: questions like ‘What are the (...) right motives to have?’ and ‘What kind of person ought I be?’. These objections have been taken to motivate a move to global consequentialism, on which acts are not the only subjects of normative assessment. Motives and decision-procedures are also judged right or wrong by direct reference to their consequences. In this paper, I argue that these objections fail to motivate the move from act to global consequentialism. (shrink)

We characterize a type of functional explanation that addresses why a homologous trait originating deep in the evolutionary history of a group remains widespread and largely unchanged across the group’s lineages. We argue that biologists regularly provide this type of explanation when they attribute conserved functions to phenotypic and genetic traits. The concept of conserved function applies broadly to many biological domains, and we illustrate its importance using examples of molecular sequence alignments at the intersection of evolution and cell biology. (...) We use these examples to show how the study of conserved functions can integrate knowledge of a trait’s causal effects on fitness and its history of natural selection without invoking adaptation. We also show how conserved function provides a novel basis for addressing objections against evolutionary functions raised by Robert Cummins. (shrink)

This article traces the development of Sartre's metaphysics with three interrelated aims in mind. The first is to situate Sartre's metaphysical views in relation to those of his predecessors, his contemporaries, and current continental philosophy. The second is to show that Sartre's project informs some of the key changes he makes to his existentialism during his career. The third is to bring Sartre the metaphysician into dialogue with key thinkers in the current realism/antirealism debate in Continental philosophy by showing that (...) the defense of materialism he offers in his later work preserves many hard-won insights of phenomenology and has significant advantages over many contemporary articulations of realism. (shrink)

Longtermists have argued that humanity should significantly increase its efforts to prevent catastrophes like nuclear wars, pandemics, and AI disasters. But one prominent longtermist argument overshoots this conclusion: the argument also implies that humanity should reduce the risk of existential catastrophe even at extreme cost to the present generation. This overshoot means that democratic governments cannot use the longtermist argument to guide their catastrophe policy. In this paper, we show that the case for preventing catastrophe does not depend on longtermism. (...) Standard cost-benefit analysis implies that governments should spend much more on reducing catastrophic risk. We argue that a government catastrophe policy guided by cost-benefit analysis should be the goal of longtermists in the political sphere. This policy would be democratically acceptable, and it would reduce existential risk by almost as much as a strong longtermist policy. (shrink)

I argue that absolutism, the view that absolutely unrestricted quantification is possible, is to blame for both the paradoxes that arise in naive set theory and variants of these paradoxes that arise in plural logic and in semantics. The solution is restrictivism, the view that absolutely unrestricted quantification is not possible. -/- It is generally thought that absolutism is true and that restrictivism is not only false, but inexpressible. As a result, the paradoxes are blamed, not on illicit quantification, but (...) on the logical conception of set which motivates naive set theory. The accepted solution is to replace this with the iterative conception of set. -/- I show that this picture is doubly mistaken. After a close examination of the paradoxes in chapters 2--3, I argue in chapters 4 and 5 that it is possible to rescue naive set theory by restricting quantification over sets and that the resulting restrictivist set theory is expressible. In chapters 6 and 7, I argue that it is the iterative conception of set and the thesis of absolutism that should be rejected. (shrink)

This thesis consists of a series of papers in population ethics: a subfield of normative ethics concerned with the distinctive issues that arise in cases where our actions can affect the identities or number of people of who ever exist. Each paper can be read independently of the others. In Chapter 1, I present a dilemma for Archimedean views in population axiology: roughly, those views on which adding enough good lives to a population can make that population better than any (...) other. In Chapter 2, I extend Gustaf Arrhenius’s famous impossibility theorems in population axiology into the domain of choices under risk. My risky impossibility theorems dispense with the assumption that welfare levels are finitely fine-grained, and so tell against lexical views in population axiology. In Chapter 3, I present objections to critical-level and critical-range views in population axiology. I then sketch out what I call the ‘Imprecise Exchange Rates View’ and argue that it is an attractive alternative. In Chapter 4, I address critical-level and critical-range views again. This time, I note that they are vulnerable to objections from biographical identity: identity between lives. I suggest that these objections give us reason to reject critical-level and critical-range views and embrace the Total View. In Chapter 5, I argue that objections of the same form – objections from personal identity – tell against person-affecting views in population ethics. In Chapter 6, I draw out some counterintuitive implications of two recent complaints-based theories of the procreation asymmetry. (shrink)

The essay explores the systematic relationship in the work of Giordano Bruno (1548-1600) between his monadology, his metaphysics as presented in works such as De la causa, principio et uno, the mythopoeic cosmology of Lo spaccio de la bestia trionfante, and practical works like De vinculis in genere. Bruno subverts the conceptual regime of the Aristotelian substantial forms and its accompanying cosmology with a metaphysics of individuality that privileges individual unity (singularity) over formal unity and particulars over substantial forms without (...) sacrificing a metaphysical perspective on the cosmos. The particular is individuated as a unique site of desire, continually transforming but able to entrain itself and others through phantasmatic ‘bonding’, the new source of regularity in Bruno’s polycentric universe. Bruno thus tries to do justice to the demands of intelligibility as well as transformative eros. The essay concludes with a note on Bruno’s geometry as it relates to his general conception of form. (shrink)

In this article, we apply the literature on the ethics of choice-architecture (nudges) to the realm of virtual reality (VR) to point out ethical problems with using VR for empathy-based nudging. Specifically, we argue that VR simulations aiming to enhance empathic understanding of others via perspective-taking will almost always be unethical to develop or deploy. We argue that VR-based empathy enhancement not only faces traditional ethical concerns about nudge (autonomy, welfare, transparency), but also a variant of the semantic variance problem (...) that arises for intersectional perspective-taking. VR empathy simulations deceive and manipulate their users about their experiences. Despite their often laudable goals, such simulations confront significant ethical challenges. In light of these goals and challenges, we conclude by proposing that VR designers shift from designing simulations aimed at producing empathic perspective-taking to designing simulations aimed at generating sympathy. These simulations, we claim, can avoid the most serious ethical issues associated with VR nudges, semantic variance, and intersectionality. (shrink)

This paper presents what I call “the flowchart solution” to Joe Horton’s all-or-nothing problem. Rather than three options – don’t save any child, save one, or save two – there is a flowchart with a choice of don’t save or save, and then within save, save one or save two.

It’s a popular idea that memory resembles testimony insofar as each can ‘preserve’ epistemic warrant. But how does such ‘preservation’ do its epistemic work? I have elsewhere developed an assurance theory of testimonial warrant. Here, I develop an assurance theory of preservative memory. How could the ‘preservation’ of warrant through memory work through an assurance? What would even count as an intrapersonal assurance? I explain each form of preservation by contrasting the relation that preserves warrant with a pathological alternative. My (...) assurance theory of testimony theorizes the illocutionary norms governing the speech act of telling by explaining what goes wrong when there’s what Austin calls an ‘abuse.’ But what norms govern an intrapersonal memory relation? There are two sides in a memory relation: the earlier self judges that p, then memory keeps the later self in epistemic touch with that judgment by ‘preserving’ its warrant. But this is not an illocutionary relation. (When you ‘tell yourself that p,’ you are trying to ‘convince yourself’ that p and as such typically do not yet even judge that p.) I argue that the earlier self nonetheless offers an assurance by extending an invitation to trust. Your earlier self judges that p in part by projecting a future in which you will continue to trust yourself on the question whether p when you lose access to the evidence that informed the judgment. That projection of trust in yourself posits a worthiness of trust that ought to lead others to accept your testimony that p. Assurance in memory and assurance in testimony thus ought to work together. This aspect of the parallel emerges vividly when we see how it breaks down in the pathology of gaslighting – more than merely illocutionary abuse! – which targets specifically how testimony and memory work together in inviting trust relations. (shrink)

When Milan Kundera introduces the concept of graphomania, he seems to register only two extremes: the person who writes for a few known people and the person who writes for a very large audience. Joe Horton’s all-or-nothing problem provides a way of making sense of this conceptualization of the situation, though in a way that breaks with Kundera’s emphasis on a writer’s craving for audience attention.

Fragments is a verse and narrative work of phenomenological and existential ontology focusing on mind-world unity and mind-world dislocation in the experience of self through time. Pivotal experiential and historical moments -- moments when normative guardrails and unreflective models of the world may be compromised -- are approached as fundamental markers of how we transact with evolving versions of ourselves and world.

I present an example in which the all-or-nothing problem involves adults, rather than children in danger.

Joe Horton’s all-or-nothing problem concerns a situation in which it is morally permissible to do nothing and to save two people but not to save only one. This description seems to entail that we should do nothing rather than save only one. I object to Horton’s solution and challenge a principle he draws attention to, which is required to generate the problem but which Horton regards as beyond dispute.

This article reviews two standard criticisms of creationism/intelligent design (ID): it is unfalsifiable, and it is refuted by the many imperfect adaptations found in nature. Problems with both criticisms are discussed. A conception of testability is described that avoids the defects in Karl Popper’s falsifiability criterion. Although ID comes in multiple forms, which call for different criticisms, it emerges that ID fails to constitute a serious alternative to evolutionary theory.

In this chapter, I will make the case that we can accurately describe Ghazali’s position as a natural law theory. Kevin Reinhart (1995), on whose translation of al-Mustaṣfā I will be depending in what follows, has also treated this topic. Though he did not specifically compare Ghazali’s position there with natural law theory, like Hourani (1985) he interprets Ghazali’s position as subjectivist on key points rendering it incompatible with natural law theory. Thus, I will begin with a prima facie case (...) for this incompatibility roughly along the lines one finds in Reinhart, and argue that a closer examination of the relevant text of al-Mustaṣfā along with the parallel section of al-Iqtiṣād, also cited by Hourani, shows that Ghazali’s position is not conclusively subjectivist, but instead is compatible with a natural law theory. I will examine key sections of Ghazali’s Kimiya al-Sa’dāt that quite clearly express a natural law theory of morality. (shrink)

In this paper, I challenge a traditional assumption concerning the nature and aims of education. According to epistemic infallibilism, propositional knowledge requires epistemic certainty. Though some philosophers accept infallibilism, others consider it implausible because it does not recognize ordinary cases of supposed knowledge. On this objection, we possess many items of propositional knowledge, notwithstanding the fallibleness of these items. Infallibilism is inconsistent with such items and thus considered unwarranted. I articulate this kind of objection to infallibilism as it concerns education. (...) I then offer a cumulative case defense of infallibilism and evaluate that defense. This examination suggests that much of what we commonly consider as education does not provide knowledge, and therefore that the traditional assumption is incorrect. My paper has interdisciplinary interests with respect to epistemology, philosophy of education, philosophy of science, and pedagogical practice. (shrink)

Michael Scriven’s (1959) example of identical twins (who are said to be equal in fitness but unequal in their reproductive success) has been used by many philosophers of biology to discuss how fitness should be defined, how selection should be distinguished from drift, and how the environment in which a selection process occurs should be conceptualized. Here it is argued that evolutionary theory has no commitment, one way or the other, as to whether the twins are equally fit. This is (...) because the theory of natural selection is fundamentally about the fitnesses of traits, not the fitnesses of token individuals. A plausible philosophical thesis about supervenience entails that the twins are equally fit if they live in identical environments, but evolutionary biology is not committed to the thesis that the twins live in identical environments. Evolutionary theory is right to focus on traits, rather than on token individuals, because the fitnesses of token organisms (as opposed to their actual survivorship and degree of reproductive success) are almost always unknowable. This point has ramifications for the question of how Darwin’s theory of evolution and R. A. Fisher’s are conceptually different. (shrink)

The chapter discusses the principle of conservatism and traces how the general principle is related to the specific one. This tracing suggests that the principle of conservatism needs to be refined. Connecting the principle in cognitive science to more general questions about scientific inference also allows us to revisit the question of realism versus instrumentalism. The framework deployed in model selection theory is very general; it is not specific to the subject matter of science. The chapter outlines some non-Bayesian ideas (...) that have been developed in model selection theory. The principle of conservatism, like C. Lloyd Morgan's canon, describes a preference concerning kinds of parameters. It says that a model that postulates only lower-level intentionality is preferable to one that postulates higher-level intentionality if both fit the data equally well. The model selection approach to parsimony helps explain why unification is a theoretical virtue. (shrink)

We argue elsewhere that explanatoriness is evidentially irrelevant . Let H be some hypothesis, O some observation, and E the proposition that H would explain O if H and O were true. Then O screens-off E from H: Pr = Pr. This thesis, hereafter “SOT” , is defended by appeal to a representative case. The case concerns smoking and lung cancer. McCain and Poston grant that SOT holds in cases, like our case concerning smoking and lung cancer, that involve frequency (...) data. However, McCain and Poston contend that there is a wider sense of evidential relevance—wider than the sense at play in SOT—on which explanatoriness is evidentially relevant even in cases involving frequency data. This is their main point, but they also contend that SOT does not hold in certain cases not involving frequency data. We reply to each of these points and conclude with some general remarks on screening-off as a test of evidential relevance. (shrink)

We argued that explanatoriness is evidentially irrelevant in the following sense: Let H be a hypothesis, O an observation, and E the proposition that H would explain O if H and O were true. Then our claim is that Pr = Pr. We defended this screening-off thesis by discussing an example concerning smoking and cancer. Climenhaga argues that SOT is mistaken because it delivers the wrong verdict about a slightly different smoking-and-cancer case. He also considers a variant of SOT, called (...) “SOT*”, and contends that it too gives the wrong result. We here reply to Climenhaga’s arguments and suggest that SOT provides a criticism of the widely held theory of inference called “inference to the best explanation”. (shrink)

In their book What Darwin Got Wrong, Jerry Fodor and Massimo Piattelli-Palmarini construct an a priori philosophical argument and an empirical biological argument. The biological argument aims to show that natural selection is much less important in the evolutionary process than many biologists maintain. The a priori argument begins with the claim that there cannot be selection for one but not the other of two traits that are perfectly correlated in a population; it concludes that there cannot be an evolutionary (...) theory of adaptation. This article focuses mainly on the a priori argument. (shrink)

Developing a definition of group selection, and applying that definition to the dispute in the social sciences between methodological holists and methodological individualists, are the two goals of this paper. The definition proposed distinguishes between changes in groups that are due to group selection and changes in groups that are artefacts of selection processes occurring at lower levels of organization. It also explains why the existence of group selection is not implied by the mere fact that fitness values of organisms (...) are sensitive to the composition of groups. And, lastly, the definition explains why group selection need not involve selection for altruism. Group selection is thereby seen as an evolutionary force which is objectively distinct from other evolutionary forces. Applying the distinction between group and individual selection to the holism/individualism dispute has the desirable result that the dispute is not decidable a priori. This way of looking at the dispute yields a conception of individualism which is untainted by atomism and a conception of holism which is unspoiled by hypostatis. (shrink)

Is all explanations causal explanation? Puzzles about barometer readings "explain" storms and shadow lengths "explaining" flagpole heights make it attractive to think so. Wesley Salmon (1984) has endorsed this causal thesis. One way to test this thesis is to assess the explanatory import of pseudo-processes. I do so by discussing the concept of heritability, which measures a pseudo-process, and one role it played in the theory of natural selection: explaining response to selection. This will show, not just that heritability has (...) heuristic or predictive utility, but that it can be explanatory. Possible responses to this case are also discussed. (shrink)

We argue against some of Reichenbach's claims about causal forks are incorrect. We do not see why the Second Law of Thermodynamics rules out the existence of conjunctive forks open to the past. In addition, we argue that a common effect rarely forms a conjunctive fork with its joint causes, but it sometimes does. Nevertheless, we think there is something to be said for Reichenbach's idea that forks of various kinds are relevant to explaining why we know more about the (...) past than about the future. And entropy turns out to play a role in the explanation, though not the determining role that Reichenbach envisions. (shrink)

Is there some general reason to expect organisms that have beliefs to have false beliefs? And after you observe that an organism occasionally occupies a given neural state that you think encodes a perceptual belief, how do you evaluate hypotheses about the semantic content that that state has, where some of those hypotheses attribute beliefs that are sometimes false while others attribute beliefs that are always true? To address the first of these questions, we discuss evolution by natural selection and (...) show how organisms that are risk-prone in the beliefs they form can be fitter than organisms that are risk-free. To address the second question, we discuss a problem that is widely recognized in statistics – the problem of over-fitting – and one influential device for addressing that problem, the Akaike Information Criterion (AIC). We then use AIC to solve epistemological versions of the disjunction and distality problems, which are two key problems concerning what it is for a belief state to have one semantic content rather than another. (shrink)

Maximum Parsimony (MP) and Maximum Likelihood (ML) are two methods for evaluating which phlogenetic tree is best supported by data on the characteristics of leaf objects (which may be species, populations, or individual organisms). MP has been criticized for assuming that evolution proceeds parsimoniously -- that if a lineage begins in state i and ends in state j, the way it got from i to j is by the smallest number of changes. MP has been criticized for needing to assume (...) some model or other of the evolutionary process even though biologists often do not know what that process really is. This paper critically evaluates both criticisms. (shrink)