While the notion of chance has been central in discussions over the probabilistic nature of natural selection and genetic drift, its role in the production of variants on which populational sampling takes place has received much less philosophical attention. This article discusses the concept of chance in evolution in the light of contemporary work in evo-devo. We distinguish different levels at which randomness and chance can be defined in this context, and argue that recent research on variability and evolvability demands (...) a causal understanding of variational probabilities under which development acquires a creative, rather than a constraining role in evolution. We then provide a propensity interpretation of variational probabilities that solves a conceptual confusion between causal properties, variational probabilities and extant variation present in the literature, and explore some metaphysical consequences that follow from our interpretation, specifically with regards to the nature of developmental types. 2.1Mutational randomness 2.2Morphological randomness 2.3Adaptive randomness3Variability and Phenotypic Probabilities 3.1The RNA model as a model for evo-devo4Evolvability and the Probability of Evolving5Variational Propensities in Evo-Devo 5.1Individuating variational propensities 5.2Developmental types6Conclusion. (shrink)

Sustained controversy over a philosophical issue is often times symptomatic of differing commitments at a more fundamental philosophical level. I will argue that two current debates over the foundations of the theory of natural selection are cases in point. Alexander Rosenberg, at times together with Mary Williams, challenges what is becoming received orthodoxy about the foundations of this theory. He argues that the currently popular propensity interpretation of fitness does not legitimize explanations in terms of natural selection, and that furthermore, (...) the biological fields which typically study the ways in which selection pressures originate in the organism/environment complex are not in fact part of the theory of natural selection at all. His foils in the first case are Robert Brandon, John Beatty and Susan Mills;2 on the second issue he is engaged in debate with Elliott Sober.3 We will see that, although the controversies are ostensibly about the interpretation of fitness, the issues, at bottom, involve the nature of scientific explanation. (shrink)

Supervenience is a relationship which has been used recently to explain the physical determination of biological phenomena despite resistance to reduction. Supervenience, however, is plagued by ambiguities which weaken its explanatory value and obscure some interesting aspects of reduction in biology. Although I suspect that similar considerations affect the use of supervenience in ethics and the philosophy of mind, I don’t intend anything I have to say here to apply outside of the physical and biological cases I consider.The main point (...) of this paper is that there is a property of biological systems which makes it both misleading and inappropriate to reduce central biological phenomena to the properties of underlying components. Despite this, reductive explanation has been a major source of innovation in biological theory. The apparent tension can be resolved if underlying properties are explanatorily relevant to the higher level phenomena even though the latter are not strictly reducible to the former. Supervenience, I will argue, is not robust enough to deny reduction while supporting explanatory relevance. (shrink)

Several recent arguments by philosophers of biology have challenged the traditional view that evolutionary factors, such as drift and selection, are genuine causes of evolutionary outcomes. In the case of drift, advocates of the statistical theory argue that drift is merely the sampling error inherent in the other stochastic processes of evolution and thus denotes a mathematical, rather than causal, feature of populations. This debate has largely centered around one particular model of drift, the Wright–Fisher model, and this has contributed (...) to the plausibility of the statisticalists’ arguments. However, an examination of alternative, predictively inequivalent models shows that drift is a genuine cause that can be manipulated to change population outcomes. This case study illustrates the influence of methodological assumptions on ontological judgments, particularly the pernicious effect of focusing on a particular model at the expense of others and confusing its assumptions and idealizations for true claims about the phenomena being modeled. (shrink)

Recent attempts to clarify the fitness in evolutionary theory as a propensity (Brandon 1978; Brandon and Beatty 1984; Burian 1983; Mills and Beatty 1979; Sober 1984a, 1984b) or as a primitive theoretical term (Rosenberg 1983, 1985; Williams 1970, Williams and Rosenberg 1985) all miss the mark in clarifying the empirical content and explanatory power of natural selection theory.I shall argue that the crucial distinction missing in these accounts is between the sense of fitness common in population genetics as actual relative (...) rate of increase of genotypes and fitness in the more ordinary sense--and Darwin’s--of adaptedness of organisms. The relation between these senses of ‘fitness’ is that fitness as actual reproduction success depends on, is a function of, variables representing adaptive capacities and environmental properties. (shrink)

In this paper we first briefly review Bell's (1964, 1966) Theorem to see how it invalidates any deterministic "hidden variable" account of the apparent indeterminacy of quantum mechanics (QM). Then we show that quantum uncertainty, at the level of DNA mutations, can "percolate" up to have major populational effects. Interesting as this point may be it does not show any autonomous indeterminism of the evolutionary process. In the next two sections we investigate drift and natural selection as the locus of (...) autonomous biological indeterminacy. Here we conclude that the population-level indeterminacy of natural selection and drift are ultimately based on the assumption of a fundamental indeterminacy at the level of the lives and deaths of individual organisms. The following section examines this assumption and defends it from the determinists' attack. Then we show that, even if one rejects the assumption, there is still an important reason why one might think evolutionary theory (ET) is autonomously indeterministic. In the concluding section we contrast the arguments we have mounted against a deterministic hidden variable account of ET with the proof of the impossibility of such an account of QM. (shrink)

Millstein [Bio. Philos. 17 (2002) 33] correctly identies a serious problem with the view that natural selection and random drift are not conceptually distinct. She offers a solution to this problem purely in terms of differences between the processes of selection and drift. I show that this solution does not work, that it leaves the vast majority of real biological cases uncategorized. However, I do think there is a solution to the problem she raises, and I offer it here. My (...) solution depends on solving the biological analogue of the reference class problem in probability theory and on the reality of individual fitnesses. (shrink)

In this paper I argue against the claim, recently put forward by some philosophers of biology and evolutionary biologists, that there can be two or more ontologically distinct levels of selection. I show by comparing the fitness of individuals with that of collectives of individuals in the same environment and over the same period of time – as required to decide if one or more levels of selection is acting in a population – that the selection of collectives is a (...) by-product of selection at the individual level; thus, talking about two or more levels of selection represents merely a different perspective on one and the same process. (shrink)

ABSTRACTIn Darwinian Population and Natural Selection, Peter Godfrey-Smith brought the topic of natural selection back to the forefront of philosophy of biology, highlighting different issues surro...

The Darwinian theory of evolution is itself evolving and this book presents the details of the core of modern Darwinism and its latest developmental directions. The authors present current scientific work addressing theoretical problems and challenges in four sections, beginning with the concepts of evolution theory, its processes of variation, heredity, selection, adaptation and function, and its patterns of character, species, descent and life. The second part of this book scrutinizes Darwinism in the philosophy of science and its usefulness in (...) understanding ecosystems, whilst the third section deals with its application in disciplines beyond the biological sciences, including evolutionary psychology and evolutionary economics, Darwinian morality and phylolinguistics. The final section addresses anti-Darwinism, the creationist view and issues around teaching evolution in secondary schools. The reader learns how current experimental biology is opening important perspectives on the sources of variation, and thus of the very power of natural selection. This work examines numerous examples of the extension of the principle of natural selection and provides the opportunity to critically reflect on a rich theory, on the methodological rigour that presides in its extensions and exportations, and on the necessity to measure its advantages and also its limits. Scholars interested in modern Darwinism and scientific research, its concepts, research programs and controversies will find this book an excellent read, and those considering how Darwinism might evolve, how it can apply to the human sciences and other disciplines beyond its origins will find it particularly valuable. Originally produced in French (Les Mondes Darwiniens), the scope and usefulness of the book have led to the production of this English text, to reach a wider audience. This book is a milestone in the impressive penetration by Francophone scholars into the world of Darwinian science, its historiography and philosophy over the last two decades. Alex Rosenberg, R. Taylor Cole Professor of Philosophy, Duke University Until now this useful and comprehensive handbook has only been available to francophones. Thanks to this invaluable new translation, this collection of insightful and original essays can reach the global audience it deserves. Tim Lewens, University of Cambridge. (shrink)

Drift is often characterized in statistical terms. Yet such a purely statistical characterization is ambiguous for it can accept multiple physical interpretations. Because of this ambiguity it is important to distinguish what sorts of processes can lead to this statistical phenomenon. After presenting a physical interpretation of drift originating from the most popular interpretation of fitness, namely the propensity interpretation, I propose a different one starting from an analysis of the concept of drift made by Godfrey-Smith. Further on, I show (...) how my interpretation relates to previous attempts to make sense of the notion of expected value in deterministic setups. The upshot of my analysis is a physical conception of drift that is compatible with both a deterministic and indeterministic world. (shrink)

Following Wallace’s suggestion, Darwin framed his theory using Spencer’s expression “survival of the fittest”. Since then, fitness occupies a significant place in the conventional understanding of Darwinism, even though the explicit meaning of the term ‘fitness’ is rarely stated. In this paper I examine some of the different roles that fitness has played in the development of the theory. Whereas the meaning of fitness was originally understood in ecological terms, it took a statistical turn in terms of reproductive success throughout (...) the 20th Century. This has lead to the ever-increasing importance of sexually reproducing organisms and the populations they compose in evolutionary explanations. I will argue that, moving forward, evolutionary theory should look back at its ecological roots in order to be more inclusive in the type of systems it examines. Many biological systems can only be satisfactorily accounted for by offering a non-reproductive account of fitness. This argument will be made by examining biological systems with very small or transient population structures. I argue this has significant consequences for how we define Darwinism, increasing the significance of survival over that of reproduction. (shrink)

Altruism is one of the most studied topics in theoretical evolutionary biology. The debate surrounding the evolution of altruism has generally focused on the conditions under which altruism can evolve and whether it is better explained by kin selection or multilevel selection. This debate has occupied the forefront of the stage and left behind a number of equally important questions. One of them, which is the subject of this article, is whether the word “selection” in “kin selection” and “multilevel selection” (...) necessarily refers to “evolution by natural selection.” I show, using a simple individual-centered model, that once clear conditions for natural selection and altruism are specified, one can distinguish two kinds of evolution of altruism, only one of which corresponds to the evolution of altruism by natural selection, the other resulting from other evolutionary processes. (shrink)

A basic challenge to naturalistic moral realism is that, even if moral properties existed, there would be no way to naturalistically represent or track them. Here, the basic structure for a tracking account of moral epistemology is given in empirically respectable terms, based on a eudaimonist conception of morality. The goal is to show how this form of moral realism can be seen as consistent with the details of evolutionary biology as well as being amenable to the most current understanding (...) of representationalist or correspondence theories of truth. (shrink)

Perhaps the most familiar understanding of “naturalism” derives from Quine, understanding it as a continuity of empirical theories of the world as described through the scientific method. So, it might be surprising that one of the most important naturalistic moral realists, Philippa Foot, rejects standard evolutionary biology in her justly lauded _Natural Goodness_. One of her main reasons for this is the true claim that humans can flourish (eudaimonia) without reproducing, which she claims cannot be squared with evolutionary theory and (...) biology more generally. The present argument concludes that Foot was wrong to reject evolutionary theory as the empirical foundation of naturalized eudaimonist moral realism. This is based on contemporary discussion of _biological function_ and _evolutionary fitness_, from which a definition of “eudaimonia” is constructed. This gives eudaimonist moral realism an empirically respectable foundation. (shrink)

I distinguish two roles for a fitness concept in the context of explaining cumulative adaptive evolution: fitness as a predictor of gene frequency change, and fitness as a criterion for phenotypic improvement. Critics of inclusive fitness argue, correctly, that it is not an ideal fitness concept for the purpose of predicting gene-frequency change, since it relies on assumptions about the causal structure of social interaction that are unlikely to be exactly true in real populations, and that hold as approximations only (...) given a specific type of weak selection. However, Hamilton took this type of weak selection, on independent grounds, to be responsible for cumulative assembly of complex adaptations. In this special context, I argue that inclusive fitness is distinctively valuable as a criterion for improvement and a standard for optimality. Yet to call inclusive fitness a criterion for improvement and a standard for optimality is not to make any claim about the frequency with which inclusive fitness optimization actually occurs in nature. This is an empirical question that cannot be settled by theory alone. I close with some reflections on the place of inclusive fitness in the long running clash between ‘causalist’ and ‘statisticalist’ conceptions of fitness. (shrink)

In an incendiary 2010 Nature article, M. A. Nowak, C. E. Tarnita, and E. O. Wilson present a savage critique of the best-known and most widely used framework for the study of social evolution, W. D. Hamilton’s theory of kin selection. More than a hundred biologists have since rallied to the theory’s defence, but Nowak et al. maintain that their arguments ‘stand unrefuted’. Here I consider the most contentious claim Nowak et al. defend: that Hamilton’s rule, the core explanatory principle (...) of kin selection theory, ‘almost never holds’. I first distinguish two versions of Hamilton’s rule in contemporary theory: a special version (HRS) that requires restrictive assumptions, and a general version (HRG) that does not. I then show that Nowak et al. are most charitably construed as arguing that HRS almost never holds, while HRG buys its generality at the expense of explanatory power. While their arguments against HRS are fairly uncontroversial, their arguments against HRG are more contentious, yet these have been largely overlooked in the ensuing furore. I consider the arguments for and against the explanatory value of HRG, with a view to assessing what exactly is at stake in the debate. I suggest that the debate hinges on issues concerning the causal interpretability of regression coefficients, and concerning the explanatory function Hamilton’s rule is intended to serve. (shrink)

This volume focuses on various questions concerning the interpretation of probability and probabilistic reasoning in biology and physics. It is inspired by the idea that philosophers of biology and philosophers of physics who work on the foundations of their disciplines encounter similar questions and problems concerning the role and application of probability, and that interaction between the two communities will be both interesting and fruitful. In this introduction we present the background to the main questions that the volume focuses on (...) and summarize the highlights of the individual contributions. (shrink)

The prevalence of optimality models in the literature of evolutionary biology is testimony to their popularity and importance. Evolutionary biologist R. C. Lewontin, whose criticisms of optimality models are considered here, reflects that "optimality arguments have become extremely popular in the last fifteen years, and at present represent the dominant mode of thought." Although optimality models have received little attention in the philosophical literature, these models are very interesting from a philosophical point of view. As will be argued, optimality models (...) are central to evolutionary thought, yet they are not readily accomodated by the traditional view of scientific theories. According to the traditional view, we would expect optimality models to employ general, empirical laws of nature, but they do not. Fortunately, the semantic view of scientific theories, a recent alternative to the traditional view, more readily accomodates optimality models. As we would expect on the semantic view, optimality models can be construed as specifications of ideal systems. These specifications may be used to describe empirical systems--that is, the specifications may have empirical instances. But the specifications are not empirical claims, much less general, empirical laws. Although philosophers have yet to discuss the general features and uses of optimality models, these topics have stimulated much recent discussion among evolutionary biologists. Their discussions raise a number of precautions concerning the proper use of optimality models. Moreover, many of their caveats can be interpreted as general reminders that 1) optimality models specify ideal systems whose empirical instantiations may be quite restricted, and that 2) optimality models should not be construed as general, empirical laws. As G. F. Oster and E. O. Wilson caution, "the prudent course is to regard optimality models as provisional guides to further empirical research and not necessarily as the key to deeper laws of nature." It seems, then, that the semantic view of theories is more sensitive to the nature and limitations of optimality models than is the more traditional view of theories. (shrink)

Among the liveliest disputes in evolutionary biology today are disputes concerning the role of chance in evolution--more specifically, disputes concerning the relative evolutionary importance of natural selection vs. so-called "random drift". The following discussion is an attempt to sort out some of the broad issues involved in those disputes. In the first half of this paper, I try to explain the differences between evolution by natural selection and evolution by random drift. On some common construals of "natural selection", those two (...) modes of evolution are completely indistinguishable. Even on a proper construal of "natural selection", it is difficult to distinguish between the "improbable results of natural selection" and evolution by random drift. In the second half of this paper, I discuss the variety of positions taken by evolutionists with respect to the evolutionary importance of random drift vs. natural selection. I will then consider the variety of issues in question in terms of a conceptual distinction often used to describe the rise of probabilistic thinking in the sciences. I will argue, in particular, that what is going on here is not, as might appear at first sight, just another dispute about the desirability of "stochastic" vs. "deterministic" theories. Modern evolutionists do not argue so much about whether evolution is stochastic, but about how stochastic it is. (shrink)

No âmbito do debate sobre as unidades envolvidas nos processos seletivos, a controvérsia sobre a possibilidade de comportamentos genuinamente altruístas tem um lugar destacado. Partindo de uma posição declaradamente pluralista, discutir-se-ão, neste artigo, algumas questões relevantes para esse tópico. Em primeiro lugar, o altruísmo será concebido como uma propriedade fenotípica dos grupos biológicos, e não apenas de seus membros. Essa caraterização levará, em um segundo momento, à discussão sobre a relação entre grupos em sociedades complexas, como é o caso das (...) sociedades humanas. Nesse contexto, será esboçado um modelo sobre como os comportamentos altruístas e os comportamentos egoístas se solapam em níveis diferentes das dinâmicas sociais. Finalmente, será sugerido um método de análise dirigido a determinar quais forças evolutivas entram em jogo, e sobre que tipo de comportamento, em casos empíricos concretos. In the debate on the units of selection, the controversy about the possibility of genuinely altruistic behavior has a prominent place. By assuming a pluralistic position, some relevant issues on the topic will be discussed in this paper. Firstly, altruism will be conceived as a phenotypic property of biological groups, not just of their members. Secondly, this characterization will be applied to the discussion on the relationship between groups in complex societies, as humans ones. In that context, a model about how altruistic and egoistic behaviors overlap at different levels of social dynamics will be outlined. Finally, a method aimed at determining what kinds of evolutionary forces influence behavior in empirical cases will be suggested. (shrink)

Out of a concern to respect the naturalistic fallacy, Ruse (1986) argues for the possibility of causal, but not justificatory, explanations of morality in terms of evolutionary processes. In a discussion of Ruse's work, Rottschaefer and Martinsen (1990) claim that he erroneously limits the explanatory scope of evolutionary concepts, because he fails to see that one can have objective moral properties without committing either of two forms of the naturalistic fallacy, if one holds that moral properties supervene on non-moral properties. (...) In this short paper I argue that Rottschaefer and Martinsen's solution fails. If one takes moral properties to supervene on non-moral properties, then either one ends up committing one of the two forms of the naturalistic fallacy or else one is left postulating unbelievable brute metaphysical facts. (shrink)

In recent years, some have claimed that a Darwinian perspective will revolutionize the study of human society and culture. This project is viewed with disdain and suspicion, on the other hand, by many practicing social scientists. This article seeks to clear the air in this heated debate by dissociating two claims that are too often assumed to be inseparable. The first is the ‘ontological’ claim that Darwinian principles apply, at some level of abstraction, to human society and culture. The second (...) is the more ‘pragmatic’ claim that this observation necessitates substantial changes in the practices of social scientists. Even if some version of the first claim is true, I argue – which I believe is quite likely – the second does not follow. This observation ought to chasten the most overzealous advocates of Darwinian social science, as well as softening the instinctive resistance of many social scientists and historians to the genuine insights enabled by a Darwinian approach. The conclusion discusses these insights, the most important of which is a methodological prescription for normative theory. (shrink)

How to measure fitness in the theory of natural selection? A fitness measure that has been proposed in both the biological and the philosophical literature is the expected relative reproductive success. The aim of this article is to examine the relationship between expected relative reproductive success and future actual evolutionary success. Doing so will not only clarify the use of expected relative reproductive success as a fitness measure but also shed light on the role of fitness in the theory of (...) natural selection. _1_ Introduction _2_ The Role of Fitness _3_ Geometric Mean versus Expected Relative Reproductive Success _4_ Reconciliation _5_ Reconciliation Continued _6_ Alternative Justifications _7_ Conclusion. (shrink)

Several philosophers of science have advanced an instrumentalist thesis about the use of probabilities in evolutionary biology. I investigate the consequences of instrumentalism on evolutionary explanations. I take issue with Barbara Horan's (1994) argument that probabilities are unnecessary to explain evolutionary change given the underlying deterministic character of evolutionary processes. First, I question Horan's deterministic assumption. Then, I attempt to undermine her Laplacian argument by demonstrating that whether probabilities are necessary depends upon the sort of questions one is asking.

Several philosophers of science have advanced an instrumentalist thesis about the use of probabilities in evolutionary biology. I investigate the consequences of instrumentalism on evolutionary explanations. I take issue with Barbara Horan's (1994) argument that probabilities are unnecessary to explain evolutionary change given the underlying deterministic character of evolutionary processes. First, I question Horan's deterministic assumption. Then, I attempt to undermine her Laplacian argument by demonstrating that whether probabilities are necessary depends upon the sort of questions one is asking.

The assumption that natural selection alone is sufficient to explain not only which traits get fixed in a population/species, but also how they develop, has been questioned since Darwin’s times, and increasingly in the last decades. Alternative theories, linked to genetic and phenotypic processes, or to the theory of complex systems, have been proposed to explain the rise of the phenotypic variety upon which natural selection acts. In this article, we illustrate the current state of the issue and we propose (...) a logical space based on phenotypic robustness that allows a classification of evolutionary phenomena and can provide a framework for unifying all these accounts. (shrink)

Organisms' environments are thought to play a fundamental role in determining their fitness and hence in natural selection. Existing intuitive conceptions of environment are sufficient for biological practice. I argue, however, that attempts to produce a general characterization of fitness and natural selection are incomplete without the help of general conceptions of what conditions are included in the environment. Thus there is a "problem of the reference environment"—more particularly, problems of specifying principles which pick out those environmental conditions which determine (...) fitness. I distinguish various reference environment problems and propose solutions to some of them. While there has been a limited amount of work on problems concerning what I call "subenvironments", there appears to be no earlier work on problems of what I call the "whole environment". The first solution I propose for a whole environment problem specifies the overall environment for natural selection on a set of biological types present in a population over a specified period of time. The second specifies an environment relevant to extinction of types in a population; this kind of environment is especially relevant to certain kinds of long-term evolution. (shrink)

Ruth Millikan and others advocate theories which attempt to naturalize wide mental content (e.g. beliefs.

It has been argued that biological fitness cannot be defined as expected number of offspring in all contexts. Some authors argue that fitness therefore merely satisfies a common schema or that no unified mathematical characterization of fitness is possible. I argue that comparative fitness must be relativized to an evolutionary effect; thus relativized, fitness can be given a unitary mathematical characterization in terms of probabilities of producing offspring and other effects. Such fitnesses will sometimes be defined in terms of probabilities (...) of effects occurring over the long term, but these probabilities nevertheless concern effects occurring over the short term. †To contact the author, please write to: Department of Philosophy, University of Alabama at Birmingham, HB 414A, 900 13th Street South, Birmingham, AL 35294‐1260; e‐mail: [email protected]. (shrink)

I define a concept of causal probability and apply it to questions about the role of probability in evolutionary processes. Causal probability is defined in terms of manipulation of patterns in empirical outcomes by manipulating properties that realize objective probabilities. The concept of causal probability allows us see how probabilities characterized by different interpretations of probability can share a similar causal character, and does so in such way as to allow new inferences about relationships between probabilities realized in different chance (...) setups. I clarify relations between probabilities and properties defined in terms of them, and argue that certain widespread uses of computer simulations in evolutionary biology show that many probabilities relevant to evolutionary outcomes are causal probabilities. This supports the claim that higher-level properties such as biological fitness and processes such as natural selection are causal properties and processes, contrary to what some authors have argued. (shrink)

One finds intertwined with ideas at the core of evolutionary theory claims about frequencies in counterfactual and infinitely large populations of organisms, as well as in sets of populations of organisms. One also finds claims about frequencies in counterfactual and infinitely large populations—of events—at the core of an answer to a question concerning the foundations of evolutionary theory. The question is this: To what do the numerical probabilities found throughout evolutionary theory correspond? The answer in question says that evolutionary probabilities (...) are “hypothetical frequencies” (including what are sometimes called “long-run frequencies” and “long-run propensities”). In this paper, I review two arguments against hypothetical frequencies. The arguments have implications for the interpretation of evolutionary probabilities, but more importantly, they seem to raise problems for biologists’ claims about frequencies in counterfactual or infinite populations of organisms and sets of populations of organisms. I argue that when properly understood, claims about frequencies in large and infinite populations of organisms and sets of populations are not threatened by the arguments. Seeing why gives us a clearer understanding of the nature of counterfactual and infinite population claims and probability in evolutionary theory. (shrink)

One controversy about the existence of so called evolutionary forces such as natural selection and random genetic drift concerns the sense in which such “forces” can be said to interact. In this paper I explain how natural selection and random drift can interact. In particular, I show how population-level probabilities can be derived from individual-level probabilities, and explain the sense in which natural selection and drift are embodied in these population-level probabilities. I argue that whatever causal character the individual-level probabilities (...) have is then shared by the population-level probabilities, and that natural selection and random drift then have that same causal character. Moreover, natural selection and drift can then be viewed as two aspects of probability distributions over frequencies in populations of organisms. My characterization of population-level probabilities is largely neutral about what interpretation of probability is required, allowing my approach to support various positions on biological probabilities, including those which give biological probabilities one or another sort of causal character. ‡This paper has benefited from feedback on and discussions of this and earlier work. I want to thank André Ariew, Matt Barker, Lindley Darden, Patrick Forber, Nancy Hall, Mohan Matthen, Samir Okasha, Jeremy Pober, Robert Richardson, Alex Rosenberg, Eric Seidel, Denis Walsh, and Bill Wimsatt. †To contact the author, please write to: Department of Philosophy, University of Alabama at Birmingham, HB 414A, 900 13th Street South, Birmingham, AL 35294-1260; e-mail: [email protected]. (shrink)

Recent debate on the nature of probabilities in evolutionary biology has focused largely on the propensity interpretation of fitness (PIF), which defines fitness in terms of a conception of probability known as “propensity”. However, proponents of this conception of fitness have misconceived the role of probability in the constitution of fitness. First, discussions of probability and fitness have almost always focused on organism effect probability, the probability that an organism and its environment cause effects. I argue that much of the (...) probability relevant to fitness must be organism circumstance probability, the probability that an organism encounters particular, detailed circumstances within an environment, circumstances which are not the organism’s effects. Second, I argue in favor of the view that organism effect propensities either don’t exist or are not part of the basis of fitness, because they usually have values close to 0 or 1. More generally, I try to show that it is possible to develop a clearer conception of the role of probability in biological processes than earlier discussions have allowed. (shrink)

It’s recently been argued that biological fitness can’t change over the course of an organism’s life as a result of organisms’ behaviors. However, some characterizations of biological function and biological altruism tacitly or explicitly assume that an effect of a trait can change an organism’s fitness. In the first part of the paper, I explain that the core idea of changing fitness can be understood in terms of conditional probabilities defined over sequences of events in an organism’s life. The result (...) is a notion of “conditional fitness” which is static but which captures intuitions about apparent behavioral effects on fitness. The second part of the paper investigates the possibility of providing a systematic foundation for conditional fitness in terms of spaces of sequences of states of an organism and its environment. I argue that the resulting “organism–environment history conception” helps unify diverse biological perspectives, and may provide part of a metaphysics of natural selection. (shrink)

Change is the fundamental idea of evolution. Explaining the extraordinary biological change we see written in the history of genomes and fossil beds is the primary occupation of the evolutionary biologist. Yet it is a surprising fact that for the majority of evolutionary research, we have rarely studied how evolution typically unfolds in nature, in changing ecological environments, over space and time. While ecology played a major role in the eventual acceptance of the population genetic viewpoint of evolution in the (...) synthetic era (circa 1918-1956), it held a lesser role in the development of evolutionary theory until the 1980s, when we began to systematically study the evolutionary dynamics of natural populations in space and time. As a result, early evolutionary theory was initially constructed in an abstract vacuum that was unrepresentative of evolution in nature. The subtle synthesis between ecology with evolutionary biology (eco-evo synthesis) over the past 40 years has progressed our knowledge of natural selection dynamics as they are found in nature, thus revealing how natural selection varies in strength, direction, form, and, more surprisingly, level of biological organization. Natural selection can no longer be reduced to lower levels of biological organization (i.e., individuals, selfish genes) over shorter timescales but should be expanded to include adaptation at higher levels and over longer timescales. Long-term and/or emergent evolutionary phenomena, such as multilevel selection or evolvability, have thus become tenable concepts within an evolutionary biology that embraces ecology and spatiotemporal change. Evolutionary biology is currently suspended at an intermediate stage of scientific progress that calls for the organization of all the recent knowledge revealed by the eco-evo synthesis into a coherent and unified theoretical framework. This is where philosophers of biology can be of particular use, acting as a bridge between the subdisciplines of biology and inventing new theoretical strategies to organize and accommodate the recent knowledge. Philosophers have recommended transitioning away from outdated philosophies that were originally derived from physics within the philosophical zeitgeist of logical positivism (i.e., monism, reductionism, and monocausation) and toward a distinct philosophy of biology that can capture the natural complexity of multifaceted biological systems within diverse ecosystems—one that embraces the emerging philosophies of pluralism, emergence, and multicausality. Therefore, I see recent advances in ecology, evolutionary biology, and the philosophy of biology as laying the groundwork for another major biological synthesis, what I refer to as the Second Synthesis because, in many respects, it is analogous to the aims and outcomes of the first major biological synthesis (but is notably distinct from the inorganic and contrived progressive movement known as the extended evolutionary synthesis). With the general development of a distinctive philosophy of science, biology has rightfully emerged as an autonomous science. Thus, while the first synthesis legitimized biology, the Second Synthesis autonomized biology and afforded biology its own philosophy, allowing biology to finally realize its full scientific potential. (shrink)

I argue that the propensity interpretation of fitness, properly understood, not only solves the explanatory circularity problem and the mismatch problem, but can also withstand the Pandora’s box full of problems that have been thrown at it. Fitness is the propensity (i.e., probabilistic ability, based on heritable physical traits) for organisms or types of organisms to survive and reproduce in particular environments and in particular populations for a specified number of generations; if greater than one generation, “reproduction” includes descendants of (...) descendants. Fitness values can be described in terms of distributions of propensities to produce varying number of offspring and can be modeled for any number of generations using computer simulations, thus providing both predictive power and a means for comparing the fitness of different phenotypes. Fitness is a causal concept, most notably at the population level, where fitness differences are causally responsible for differences in reproductive success. Relative fitness is ultimately what matters for natural selection. (shrink)

Despite the burgeoning interest in new and more complex accounts of the organism-environment dyad by biologists and philosophers, little attention has been paid in the resulting discussions to the history of these ideas and to their deployment in disciplines outside biology—especially in the social sciences. Even in biology and philosophy, there is a lack of detailed conceptual models of the organism-environment relationship. This volume is designed to fill these lacunae by providing the first multidisciplinary discussion of the topic of organism-environment (...) interaction. It brings together scholars from history, philosophy, psychology, anthropology, medicine, and biology to discuss the common focus of their work: entangled life, or the complex interaction of organisms and environments. (shrink)

The traditional practice of establishing morphological types and investigating morphological organization has found new support from evolutionary developmental biology (evo-devo), especially with respect to the notion of body plans. Despite recurring claims that typology is at odds with evolutionary thinking, evo-devo offers mechanistic explanations of the evolutionary origin, transformation, and evolvability of morphological organization. In parallel, philosophers have developed non-essentialist conceptions of natural kinds that permit kinds to exhibit variation and undergo change. This not only facilitates a construal of species (...) and higher taxa as natural kinds, but also broadens our perspective on the diversity of kinds found in biology. There are many different natural kinds relevant to the investigative and explanatory aims of evo-devo, including homologues and developmental modules. (shrink)

There is surprisingly little philosophical work on conceptually spelling out the difference between the traits on which natural selection may be said to act (e.g. “having a high running speed”) and mere circumstantial traits (e.g. “happening to be in the path of a forest fire”). I label this issue the “selectable traits problem” and, in this paper, I propose a solution for it. I first show that, contrary to our first intuition, simply equating selectable traits with heritable ones is not (...) an adequate solution. I then go on to argue that two recent philosophical solutions to this problem—due to Peter Godfrey-Smith and Pierrick Bourrat—are unconvincing because they cannot accommodate frequency-dependent selection. The way out of this difficulty is, I argue, to accept that extrinsic properties dependent on relations between intrinsic properties of the population members should also count as selectable traits. I then show that my proposal is legitimized by more than the simple accommodation of frequency-dependent selection. (shrink)

In identifying intrinsic molecular chance and extrinsic adaptive pressures as the only causally relevant factors in the process of evolution, the theoretical perspective of the Modern Synthesis had a major impact on the perceived tenability of an ontology of dispositional properties. However, since the late 1970s, an increasing number of evolutionary biologists have challenged the descriptive and explanatory adequacy of this “chance alone, extrinsic only” understanding of evolutionary change. Because morphological studies of homology, convergence, and teratology have revealed a space (...) of possible forms and phylogenetic trajectories that is considerably more restricted than expected, evo-devo has focused on the causal contribution of intrinsic developmental processes to the course of evolution. Evo-devo’s investigation into the developmental structure of the modality of morphology – including both the possibility and impossibility of organismal form – has led to the utilisation of a number of dispositional concepts that emphasise the tendency of the evolutionary process to change along certain routes. In this sense, and in contrast to the perspective of the Modern Synthesis, evo-devo can be described as a “science of dispositions.” This chapter discusses the recent philosophical literature on dispositional properties in evo-devo, exploring debates about both the metaphysical and epistemological aspects of the central dispositional concepts utilised in contemporary evo-devo and addressing the epistemological question of how dispositional properties challenge existing explanatory models in evolutionary biology. (shrink)

This paper justifies the inference of probabilities from symmetries. I supply some examples of important and correct inferences of this variety. Two explanations of such inferences -- an explanation based on the Principle of Indifference and a proposal due to Poincaré and Reichenbach -- are considered and rejected. I conclude with my own account, in which the inferences in question are shown to be warranted a posteriori, provided that they are based on symmetries in the mechanisms of chance setups.

I argue that there are at least four different ways in which the term ‘function’ is used in connection with the study of living organisms, namely: function as activity, function as biological role, function as biological advantage, and function as selected effect. Notion refers to what an item does by itself; refers to the contribution of an item or activity to a complex activity or capacity of an organism; refers to the value for the organism of an item having a (...) certain character rather than another; refers to the way in which a trait acquired and has maintained its current share in the population. The recognition of a separate notion of function as biological advantage solves the problem of the indeterminate reference situation that has been raised against a counterfactual analysis of function, and emphasizes the importance of counterfactual comparison in the explanatory practice of organismal biology. This reveals a neglected problem in the philosophy of biology, namely that of accounting for the insights provided by counterfactual comparison. (shrink)

I argue that there are at least four different ways in which the term ‘function’ is used in connection with the study of living organisms, namely: function as activity, function as biological role, function as biological advantage, and function as selected effect. Notion refers to what an item does by itself; refers to the contribution of an item or activity to a complex activity or capacity of an organism; refers to the value for the organism of an item having a (...) certain character rather than another; refers to the way in which a trait acquired and has maintained its current share in the population. The recognition of a separate notion of function as biological advantage solves the problem of the indeterminate reference situation that has been raised against a counterfactual analysis of function, and emphasizes the importance of counterfactual comparison in the explanatory practice of organismal biology. This reveals a neglected problem in the philosophy of biology, namely that of accounting for the insights provided by counterfactual comparison. (shrink)

The supervenience and multiple realizability of biological properties have been invoked to support a disunified picture of the biological sciences. I argue that supervenience does not capture the relation between fitness and an organism's physical properties. The actual relation is one of causal dependence and is, therefore, amenable to causal explanation. A case from optimality theory is presented and interpreted as a microreductive explanation of fitness difference. Such microreductions can have considerable scope. Implications are discussed for reductive physicalism in evolutionary (...) biology and for the unity of science. (shrink)

Susan Mills and John Beatty proposed a propensity interpretation of fitness (1979) to show that Darwinian explanations are not circular, but they did not address the critics' chief complaint that the principle of the survival of the fittest is either tautological or untestable. I show that the propensity interpretation cannot rescue the principle from the critics' charges. The critics, however, incorrectly assume that there is nothing more to Darwin's theory than the survival of the fittest. While Darwinians all scoff at (...) this assumption, they do not agree about what role, if any, this principle plays in Darwin's theory of natural selection. I argue that the principle has no place in Darwin's theory. His theory does include the idea that some organisms are fitter than others. But greater reproductive success is simply inferred from higher fitness. There is no reason to embody this inference in the form of a special principle of the survival of the fittest. (shrink)