Really statistical explanation is a hitherto neglected form of noncausal scientific explanation. Explanations in population biology that appeal to drift are RS explanations. An RS explanation supplies a kind of understanding that a causal explanation of the same result cannot supply. Roughly speaking, an RS explanation shows the result to be mere statistical fallout.

Contingency-theorists have gestured to a series of phenomena such as random mutations or rare Armageddon-like events as that which accounts for evolutionary contingency. These phenomena constitute a class, which may be aptly called the ‘sources of contingency’. In this paper, I offer a probabilistic conception of what it is to be a source of contingency and then examine two major candidates: chance variation and genetic drift, both of which have historically been taken to be ‘chancy’ in a number of different (...) senses. However,contrathe gesturing of contingency-theorists, chance variation and genetic drift are not always strong sources of contingency, as they can be non-chancy in at least one sense that opposes evolutionary contingency. The probabilistic conception offered herein allows for sources of contingency to appropriately vary in strength. To this end, I import Shannon’sinformation entropyas a statistical measure for systematically assessing the strength of a source of contingency, which is part and parcel of identifying sources of contingency. In brief, the higher the entropy, the greater the strength. This is also empirically significant because molecular, mutational, and replicative studies often contain sufficient frequency or probability data to allow for entropies to be calculated. In this way, contingency-theorists can evaluate the strength of a source of contingency in real-world cases. Moreover, the probabilistic conception also makes conceptual room for the converse of sources of contingency: ‘sources of directionality’, which ought to be recognised, as they can interact with genuine sources of contingency in undermining evolutionary contingency. (shrink)

There are two competing interpretations of the modern synthesis theory of evolution: the dynamical (also know as ‘traditional’) and the statistical. The dynamical interpretation maintains that explanations offered under the auspices of the modern synthesis theory articulate the causes of evolution. It interprets selection and drift as causes of population change. The statistical interpretation holds that modern synthesis explanations merely cite the statistical structure of populations. This paper offers a defense of statisticalism. It argues that a change in trait frequencies (...) in a population can be attributed only to selection or drift against the background of a particular statistical description of the population. The traditionalist supposition that selection and drift are description‐independent causes of population change leads the dynamical interpretation into a dilemma: it must face a contradiction or accept the loss of explanatory power. (shrink)

Over the past fifteen years there has been a considerable amount of debate concerning what theoretical population dynamic models tell us about the nature of natural selection and drift. On the causal interpretation, these models describe the causes of population change. On the statistical interpretation, the models of population dynamics models specify statistical parameters that explain, predict, and quantify changes in population structure, without identifying the causes of those changes. Selection and drift are part of a statistical description of population (...) change; they are not discrete, apportionable causes. Our objective here is to provide a definitive statement of the statistical position, so as to allay some confusions in the current literature. We outline four commitments that are central to statisticalism. They are: 1. Natural Selection is a higher order effect; 2. Trait fitness is primitive; 3. Modern Synthesis (MS)-models are substrate neutral; 4. MS-selection and drift are model-relative. (shrink)

The traditional view of evolutionary theory asserts that we can usefully understand natural selection, drift, mutation, migration, and the system of mating as forces that cause evolutionary change. Recently, Denis Walsh and Robert Brandon have objected to this view. Walsh argues that the traditional view faces a fatal dilemma and that the force analogy must be rejected altogether. Brandon accepts the force analogy but argues that drift, rather than the Hardy-Weinberg law, is the best candidate for a zero-force law. Here (...) I defend the traditional view against these objections. (shrink)

Current Perspectives in Philosophy of Biology.

The propensity account of fitness intends to solve the classical tautologicity issue by identifying fitness with a disposition, the ability to survive and reproduce. As proponents recognized early on, this account requires operational independence from actual reproductive success to avoid circularity and vacuousness charges. They suggested that operational independence is achieved by measuring fitness values through optimality models. Our goal in this article is to develop this suggestion. We show that one plausible procedure by which these independent operationalizations could be (...) thought to take place, and which is in accordance with what is said in the optimality literature, is unsound. We provide two independent lines of reasoning to show this. We then provide a sketch of a more adequate account of the role of optimality models in evolutionary contexts and draw some consequences. (shrink)

En un libro reciente McShea y Brandon defienden que la diversidad y la complejidad de la vida se explican, principalmente, por la acción de un principio que llaman “la ley evolutiva de fuerzas cero” o “ZFEL”. Tal principio actuaría de un modo implícito por detrás de muchas explicaciones de la biología, pero nunca habría sido explicitado. Asumiendo que esta idea es interesante, y que los autores en cuestión tienen razón, discutiremos el modo metateórico en que presentan dicho principio, como siendo (...) parte de la teoría de la probabilidad. Esto permite a los autores afirmar que la teoría de la probabilidad brindaría la base reductiva para toda la biología evolutiva (dado que consideran que otros principios, como el de selección natural, también serían parte de la teoría de la probabilidad). Defenderemos que, efectivamente, ZFEL no es propio de la biología únicamente, pero no por formar parte de la teoría de la probabilidad, sino por tratarse de una versión específica del principio de causa común. -/- In a recent book, McShea and Brandon argue that the observed diversity and complexity of life are explainable by a principle they call the “zero-force evolutionary law” or “ZFEL”. Although this principle would be implicit in many explanations given by biologists, it would have never been made explicit. Assuming that this idea is interesting, and that the authors are right, we will discuss the metatheoretical way in which they present said principle, as being a part of probability theory. This allows the authors to claim that probability theory provides the reductive basis for all evolutionary biology. We will defend, in accordance with them, that ZFEL is not a solely biological principle, but not because it is a part of probability theory, but rather because it is a specific version of the principle of common cause. (shrink)

This article elaborates on McShea and Brandon’s idea that drift is unlike the rest of the evolutionary factors because it is constitutive rather than imposed on the evolutionary process. I show that the way they spelled out this idea renders it inadequate and is the reason why it received some objections. I propose a different way in which their point could be understood, that rests on two general distinctions. The first is a distinction between the underlying mathematical apparatus used to (...) formulate a theory and a concept proposed by that theory. With the aid of a formal reconstruction of a population genetic model, I show that drift belongs to the first category. That is, that drift is constitutive of population genetics in the same sense that multiplication is constitutive in classical mechanics, or that circle is constitutive in Ptolemaic astronomy. The second distinction is between eliminating a concept from a theory and setting its value to zero. I will show that even though drift can be set to zero just like the rest of the evolutionary factors, eliminating drift is much harder than eliminating those other factors, since it would require changing the entire mathematical apparatus of standard population genetic theory. I conclude by drawing some other implications from the proposed formal reconstruction. (shrink)

This article elaborates on McShea and Brandon’s idea that drift is unlike the rest of the evolutionary factors because it is constitutive rather than imposed on the evolutionary process. I show that the way they spelled out this idea renders it inadequate and is the reason why it received some objections. I propose a different way in which their point could be understood, that rests on two general distinctions. The first is a distinction between the underlying mathematical apparatus used to (...) formulate a theory and a concept proposed by that theory. With the aid of a formal reconstruction of a population genetic model, I show that drift belongs to the first category. That is, that drift is constitutive of population genetics in the same sense that multiplication is constitutive in classical mechanics, or that circle is constitutive in Ptolemaic astronomy. The second distinction is between eliminating a concept from a theory and setting its value to zero. I will show that even though drift can be set to zero just like the rest of the evolutionary factors, eliminating drift is much harder than eliminating those other factors, since it would require changing the entire mathematical apparatus of standard population genetic theory. I conclude by drawing some other implications from the proposed formal reconstruction. (shrink)

The adequacy of Elliott Sober’s analogy between classical mechanics and evolutionary theory—according to which both theories explain via a zero-force law and a set of forces that alter the zero-force state—has been criticized from various points of view. I focus here on McShea and Brandon’s claim that drift shouldn’t be considered a force because it is not directional. I argue that there are a number of different theses that could be meant by this, and show that one of those theses—the (...) idea that drift cannot bias populations to be taken somewhere in the evolutionary space from one generation to the next—is actually false. Not only has this thesis been implicitly assumed in the discussion of the force analogy thus far, but it is also commonly found in a wider range of philosophical and biological texts. I argue that correcting this view, and the usual images associated with it, will thereby bring heuristic benefits that impact the force analogy discussion, but that also go beyond it. (shrink)

RESUMO No Curso de Inverno de 1928/29, Heidegger afirmou que a matematização irrestrita no conhecimento dos seres vivos resultaria numa falha no propósito de elaborar a ontologia da vida orgânica. No presente artigo, examino as razões que justificam essa concepção. Com base em interpretações das investigações de biólogos como Hans Driesch J. v. Uexküll e Hans Spemann, o argumento de Heidegger integra quatro passos: 1) uma abordagem mereológica do corpo orgânico, concebido como uma unidade funcional de aptidões e intrinsecamente relacionado (...) a um ambiente; 2) uma análise formal da constituição dinâmica das aptidões, cuja estrutura pulsional consiste no atravessamento regulatório de uma dimensão; 3) uma interpretação do princípio de unificação das aptidões em termos da aptidão para comportar-se com algo em um ambiente. Esta argumentação leva a duas conclusões gerais: a matematização irrestrita implica uma descrição mecânica que supõe a desconsideração da determinação modal dos organismos; a estrutura dimensional, regulatória e protointencional das aptidões orgânicas é o fator limitante da matematização da vida.ABSTRACT In the Winter Course of 1928/29, Heidegger declared that an unrestricted mathematical determination in the knowledge of living beings would imply a failure in the purpose of developing the ontology for organic life. In this paper, I examine the reasons that justify this idea. Based on interpretations of biological researches carried by Hans Driesch, J. v. Uexküll and Hans Spemann, Heidegger’s argument has three steps 1) a mereological account of the organic body, which is conceived both as a functional unity of capabilities and as intrinsically related to an environment; 2) a formal analysis of the dynamic constitution of capabilities, which instinctually driven structure is a regulatory traversing of a dimension; 3) an interpretation of the unification principle of capabilities, which is conceived as a capability of behaving towards something within an environment. This argument entails two general conclusions: first, the unrestricted mathematical determination implies a mechanical description that presupposes the neglect of the modal structure of organisms; second, the dimensional, regulatory and proto-intentional structure of the organic capabilities is the limiting factor of the mathematical determination of living organisms. (shrink)

In this paper, I argue (contra some recent philosophical work) that an objective distinction between natural selection and drift can be drawn. I draw this distinction by conceiving of drift, in the most fundamental sense, as an individual-level phenomenon. This goes against some other attempts to distinguish selection from drift, which have argued either that drift is a population-level process or that it is a population-level product. Instead of identifying drift with population-level features, the account introduced here can explain these (...) population-level features based on a property that I label driftability. Additionally, this account shows that biology’s “first law”—the Principle of Drift (Brandon, J Phil 102(7):319–335 2006)—is not a foundational law, but is a consequence of driftability. (shrink)

I analyze here biological regression equations known in the literature as allometries and scaling laws. My focus is on the alleged lawlike status of these equations. In particular I argue against recent views that regard allometries and scaling laws as representing universal, non-continent, and/or strict biological laws. Although allometries and scaling laws appear to be generalizations applying to many taxa, they are neither universal nor exceptionless. In fact there appear to be exceptions to all of them. Nor are the constants (...) in allometries and scaling laws truly constant, stable, or universal in character, but vary in value across different taxa and background conditions. Moreover, these equations represent evolutionary, strongly contingent generalizations, which threatens their lawlike status. Lastly, allometries and scaling laws do not offer stable probabilities to which they hold in different backgrounds. I further suggest that many allometries and scaling laws function to elucidate explananda rather than explanantia or covering laws. (shrink)

What does human evolutionary theory reveal about the origins of human nature and the constraints it imposes on human cognition, behavior, and society? “The whole field of human evolution is pregnant with philosophical questions of great interest”, Michael Ruse concludes in the final passage of The Philosophy of Human Evolution. This engaging and eminently readable romp through the philosophical landscape of human evolution fills a significant niche in the existing literature. There are numerous scientific texts surveying historical and contemporary problems (...) in the field of human evolution, and there are many philosophical texts exploring conceptual and methodological problems in evolutionary theory. Ruse interweaves scientific and philosophical work on human evolution with the latest work in biological theory to produce a unique and timely book, one that addresses a range of important topics that rarely find their way into works of this genre. With a relentless lucidity and charming, f .. (shrink)

There is a tendency in both scientific and humanistic disciplines to think of biological evolution in humans as significantly impeded if not completely overwhelmed by the robust cultural and technological capabilities of the species. The aim of this article is to make sense of and evaluate this claim. In Section 2 , I flesh out the argument that humans are ‘insulated’ from ordinary evolutionary mechanisms in terms of our contemporary biological understandings of phenotypic plasticity, niche construction, and cultural transmission. In (...) Section 3 , I consider two obvious objections to the above argument based on the growing literatures related to gene-culture coevolution and recent positive selection on the human genome, as well as a pair of less common objections relating to the connection between plasticity, population size and evolvability. In Section 4 , I argue that both the ‘human evolutionary stasis argument’ and its various detractor theories are premised on a fundamental conceptual flaw: they take evolutionary stasis for granted, since they fail to conceive of stabilizing selection as a type of evolution and drift as a universal tendency that dominates in the absence of selection. Without the continued operation of natural selection, the very properties that are purported to reduce the evolutionary response to selection in humans would themselves drift into non-functionality. I conclude that properly conceived, biological evolution is a permanent and ineradicable fixture of any species, including Homo sapiens. (shrink)

The dominant view in the cognitive science of religion (the ‘Standard Model’) is that religious belief and behaviour are not adaptive traits but rather incidental byproducts of the cognitive architecture of mind. Because evidence for the Standard Model is inconclusive, the case for it depends crucially on its alleged methodological superiority to selectionist alternatives. However, we show that the Standard Model has both methodological and evidential disadvantages when compared with selectionist alternatives. We also consider a pluralistic approach, which holds that (...) religion or various aspects of religion originated as byproducts of evolved cognitive structures but were subsequently co-opted for adaptive purposes. We argue that when properly formulated, the pluralistic approach also has certain advantages over the Standard Model. (shrink)

Liberal proponents of genetic engineering maintain that developing human germline modification technologies is morally desirable because it will result in a net improvement in human health and well-being. Skeptics of germline modification, in contrast, fear evolutionary harms that could flow from intervening in the human germline, and worry that such programs, even if well intentioned, could lead to a recapitulation of the scientifically and morally discredited projects of the old eugenics. Some bioconservatives have appealed as well to the value of (...) retaining our “given” human biological nature as a reason for restraining the development and use of human genetic modification technologies even where they would tend to increase well-being. In this article, I argue that germline intervention will be necessary merely to sustain the levels of genetic health that we presently enjoy for future generations—a goal that should appeal to bioliberals and bioconservatives alike. This is due to the population-genetic consequences of relaxed selection pressures in human populations caused by the increasing efficacy and availability of conventional medicine. This heterodox conclusion, which I present as a problem of intergenerational justice, has been overlooked in medicine and bioethics due to certain misconceptions about human evolution, which I attempt to rectify, as well as the sordid history of Darwinian approaches to medicine and social policy, which I distinguish from the present argument. (shrink)

One hotly debated philosophical question in the analysis of evolutionary theory concerns whether or not evolution and the various factors which constitute it may profitably be considered as analogous to “forces” in the traditional, Newtonian sense. Several compelling arguments assert that the force picture is incoherent, due to the peculiar nature of genetic drift. I consider two of those arguments here – that drift lacks a predictable direction, and that drift is constitutive of evolutionary systems – and show that they (...) both fail to demonstrate that a view of genetic drift as a force is untenable. I go on to diagnose the reasons for the stubborn persistence of this problem, considering two open philosophical issues and offering some preliminary arguments in support of the force metaphor. (shrink)

The concept of population thinking was introduced by Ernst Mayr as the right way of thinking about the biological domain, but it is difficult to find an interpretation of this notion that is both unproblematic and does the theoretical work it was intended to do. I argue that, properly conceived, Mayr’s population thinking is a version of trope nominalism: the view that biological property-types do not exist or at least they play no explanatory role. Further, although population thinking has been (...) traditionally used to argue against essentialism about biological kinds, recently it has been suggested that it may be consistent with at least some forms of essentialism—ones that construe essential properties as relational. I argue that if population thinking is a version of trope nominalism, then, as Mayr originally claimed, it rules out any version of essentialism about biological kinds. (shrink)

According to a once influential view of selection, it consists of repeated cycles of replication and interaction. It has been argued that this view is wrong: replication is not necessary for evolution by natural selection. I analyze the nine most influential arguments for this claim and defend the replication–interaction conception of selection against these objections. In order to do so, however, the replication–interaction conception of selection needs to be modified significantly. My proposal is that replication is not the copying of (...) an entity, the replicator, but the copying of a property. Thus, we can have a replication process without there being a replicator that is being copied. (shrink)

A hitherto neglected form of explanation is explored, especially its role in population genetics. “Statistically abstractive explanation” (SA explanation) mandates the suppression of factors probabilistically relevant to an explanandum when these factors are extraneous to the theoretical project being pursued. When these factors are suppressed, the explanandum is rendered uncertain. But this uncertainty traces to the theoretically constrained character of SA explanation, not to any real indeterminacy. Random genetic drift is an artifact of such uncertainty, and it is therefore wrong (...) to reify it as a cause of evolution or as a process in its own right. *Received July 2009. †To contact the author, please write to: Department of Philosophy, University of Toronto, 170 St. George St., Toronto, ON M5R 2M8, Canada; e‐mail: [email protected]. (shrink)

Elliott Sober and his defenders think of selection, drift, mutation, and migration as distinct evolutionary forces. This paper exposes an ambiguity in Sober's account of the force of selection: sometimes he appears to equate the force of selection with variation in fitness, sometimes with ‘selection for properties’. Sober's own account of fitness as a property analogous to life-expectancy shows how the two conceptions come apart. Cases where there is selection against variance in offspring number also show that selection and drift (...) cannot be distinguished in the way Sober hopes for. These issues have significance beyond the parochial matter of the coherence of Sober's system. There is no good principled answer to the question of which features of a population should count among the contributors to fitness. This means there is no non-arbitrary account of the nature of selection. (shrink)

Certain scientific explanations of physical facts have recently been characterized as distinctively mathematical –that is, as mathematical in a different way from ordinary explanations that employ mathematics. This article identifies what it is that makes some scientific explanations distinctively mathematical and how such explanations work. These explanations are non-causal, but this does not mean that they fail to cite the explanandum’s causes, that they abstract away from detailed causal histories, or that they cite no natural laws. Rather, in these explanations, (...) the facts doing the explaining are modally stronger than ordinary causal laws or are understood in the why question’s context to be constitutive of the physical arrangement at issue. A distinctively mathematical explanation works by showing the explanandum to be more necessary than ordinary causal laws could render it. Distinctively mathematical explanations thus supply a kind of understanding that causal explanations cannot. 1 Introduction2 Some Distinctively Mathematical Scientific Explanations3 Are Distinctively Mathematical Explanations Set Apart by their Failure to Cite Causes? 4 Distinctively Mathematical Explanations do not Exploit Causal Powers5 How these Distinctively Mathematical Explanations Work6 Conclusion. (shrink)

Really statistical explanation is a hitherto neglected form of noncausal scientific explanation. Explanations in population biology that appeal to drift are RS explanations. An RS explanation supplies a kind of understanding that a causal explanation of the same result cannot supply. Roughly speaking, an RS explanation shows the result to be mere statistical fallout.

In this article, I propose a new way of thinking about natural necessity and a new way of thinking about biological laws. I suggest that much of the lack of progress in making a positive case for distinctively biological laws is that we’ve been looking for necessity in the wrong place. The trend has been to look for exceptionlessness at the level of the outcomes of biological processes and to build one’s claims about necessity off of that. However, as Beatty (...) (1995) observed, even when we are lucky enough to find a biological ‘rule’ of some sort, that rule is apt to be a victim of ‘the rule-breaking capabilities of evolutionary change’. If indeed no distinctively biological generalization—even an exceptionless one—is safe, we need to locate necessity elsewhere. A good place to start is, I think, precisely the point at which Beatty sees the possibility of lawhood as breaking down—namely, at the level of chances. 1 The ‘Necessity’ Objection to Biological Laws2 Necessary Chances2.1 Necessary chances: random drift2.2 Necessary chances: fitness3 But is it Biological?4 Conclusion. (shrink)

The concept of fitness has generated a lot of discussion in philosophy of biology. There is, however, relative agreement about the need to distinguish at least two uses of the term: ecological fitness on the one hand, and population genetics fitness on the other. The goal of this paper is to give an explication of the concept of ecological fitness by providing a reconstruction of the theory of natural selection in which this concept was framed, that is, based on the (...) way the theory was put to use in Darwin’s main texts. I will contend that this reconstruction enables us to account for the current use of the theory of natural selection. The framework presupposed in the analysis will be that of metatheoretical structuralism. This framework will provide both a better understanding of the nature of ecological fitness and a more complete reconstruction of the theory. In particular, it will provide what I think is a better way of understanding how the concept of fitness is applied through heterogeneous cases. One of the major advantages of my way of thinking about natural selection theory is that it would not have the peculiar metatheoretical status that it has in other available views. I will argue that in order to achieve these goals it is necessary to make several concepts explicit, concepts that are frequently omitted in usual reconstructions. (shrink)

There has recently been a renewed interest in the “force” interpretation of evolutionary biology. In this article, I present the general structure of the arguments for the force interpretation and identify a problem in its overly permissive conditions for being a Newtonian force. I then attempt a solution that (1) helps to illuminate the difference between forces and other types of causes and (2) makes room for random genetic drift as a force. In particular, I argue that forces are not (...) different in kind from other types of causes but rather that forces are situated on a continuum of causes distinguished by their unifying power. †To contact the author, please write to: Department of Philosophy, University of Wisconsin–Madison, 5185 Helen C. White Hall, Madison, WI 53706; e‐mail: [email protected]. (shrink)

By briefly reviewing three well-known scientific revolutions in fundamental physics (the discovery of inertia, of special relativity and of general relativity), I claim that problems that were supposed to be crying for a dynamical explanation in the old paradigm ended up receiving a structural explanation in the new one. This claim is meant to give more substance to Kuhn’s view that revolutions are accompanied by a shift in what needs to be explained, while suggesting at the same time the existence (...) of a pattern that is common to all of the discussed case-studies. It remains to be seen whether also quantum mechanics, in particular entanglement, conforms to this pattern. (shrink)

The epistemic status of Natural Selection has seemed intriguing to biologists and philosophers since the very beginning of the theory to our present times. One prominent contemporary example is Elliott Sober, who claims that NS, and some other theories in biology, and maybe in economics, are peculiar in including explanatory models/conditionals that are a priori in a sense in which explanatory models/conditionals in Classical Mechanics and most other standard theories are not. Sober’s argument focuses on some “would promote” sentences that (...) according to him, play a central role in NS explanations and are both causal and a priori. Lange and Rosenberg criticize Sober arguing that, though there may be some unspecific a priori causal claims, there are not a priori causal claims that specify particular causal factors. Although we basically agree with Lange and Rosenberg’s criticism, we think it remains silent about a second important element in Sober’s dialectics, namely his claim that, contrary to what happens in mechanics, in NS explanatory conditionals are a priori, and that this is so in quite specific explanatory models. In this paper we criticize this second element of Sober’s argument by analyzing what we take to be the four possible interpretations of Sober’s claim, and argue that, terminological preferences aside, the possible senses in which explanatory models in NS can qualify, or include elements that can qualify, as a priori, also apply to CM and other standard, highly unified theories. We conclude that this second claim is unsound, or at least that more needs to be said in order to sustain that NS explanatory models are a priori in a sense in which CM models are not. (shrink)

It is an ongoing controversy whether natural selection is a cause of population change, or a mere statistical description of how individual births and deaths accumulate. In this paper I restate the problem in terms of the reference class problem, and propose how the structure of stable equilibrium can provide a solution in continuity with biological practice. Insofar natural selection can be understood as a tendency towards equilibrium, key statisticalist criticisms are avoided. Further, in a modification of the Newtonian-force analogy, (...) it can be suggested that a better metaphor for natural selection is that of an emergent force, similar in nature to entropic forces: with magnitude and direction, but lacking a spatiotemporal origin or point of application. (shrink)

In a recent paper, Sahotra Sarkar compares the Standard Dynamical interpretation of natural selection with the Information-Theoretic interpretation from Steven A. Frank. I address Sarkar’s three arguments against Frank’s interpretation. I show that Sarkar’s major argument that a key component of Frank’s account “does not have any natural biological interpretation” is premised on a contradiction stemming from a mathematical error. Consequently, Sarkar’s major argument is unsound. I also address Sarkar’s claim that a central equation in Frank’s interpretation is dynamically insufficient (...) and his claim that Frank’s interpretation uses nonintuitive parameters to simply rewrite familiar results. (shrink)

Genic selectionists (Williams 1966; Dawkins 1976) defend the view that genes are the (unique) units of selection and that all evolutionary events can be adequately represented at the genic level. Pluralistic genic selectionists (Sterelny and Kitcher 1988; Waters 1991; Dawkins 1982) defend the weaker view that in many cases there are multiple equally adequate accounts of evolutionary events, but that always among the set of equally adequate representations will be one at the genic level. We describe a range of cases (...) all involving stable equilibria actively maintained by selection. In these cases genotypic models correctly show that selection is active at the equilibrium point. In contrast, the genic models have selection disappearing at equilibrium. For deterministic models this difference makes no difference. However, once drift is added in, the two sets of models diverge in their predicted evolutionary trajectories. Thus, contrary to received wisdom on this matter, the two sets of models are not empirically equivalent. Moreover, the genic models get the facts wrong. (shrink)

Barrett et al. present four puzzles for the ZFEL-view of evolution that we present in our 2010 book, Biology’s First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems. Our intent in writing this book was to present a radically different way to think about evolution. To the extent that it really is radical, it will be easy to misunderstand. We think Barrett et al. have misunderstood several crucial points and so we welcome the opportunity to clarify.

Recently philosophers of biology have argued over whether or not Newtonian mechanics provides a useful analogy for thinking about evolutionary theory. For philosophers, the canonical presentation of this analogy is Sober's. Matthen and Ariew and Walsh, Lewins, and Ariew argue that this analogy is deeply wrong-headed. Here I argue that the analogy is indeed useful, however, not in the way it is usually interpreted. The Newtonian analogy depends on having the proper analogue of Newton's First Law. That analogue is what (...) McShea and Brandon call the Zero Force Evolutionary Law. According to the ZFEL, change, not stasis, is the default state of evolutionary systems. (shrink)

In their 2010 book, Biology’s First Law, D. McShea and R. Brandon present a principle that they call ‘‘ZFEL,’’ the zero force evolutionary law. ZFEL says (roughly) that when there are no evolutionary forces acting on a population, the population’s complexity (i.e., how diverse its member organisms are) will increase. Here we develop criticisms of ZFEL and describe a different law of evolution; it says that diversity and complexity do not change when there are no evolutionary causes.

Darwin's theory of evolution by natural selection provided the first, and only, causal-mechanistic account of the existence of adaptations in nature. As such, it provided the first, and only, scientific alternative to the “argument from design”. That alone would account for its philosophical significance. But the theory also raises other philosophical questions not encountered in the study of the theories of physics. Unfortunately the concept of natural selection is intimately intertwined with the other basic concepts of evolutionary theory—such as the (...) concepts of fitness and adaptation —that are themselves philosophically controversial. Fortunately we can make considerable headway in getting clear on natural selection without solving all of those outstanding problems. (shrink)

The concept of developmental constraint was at the heart of developmental approaches to evolution of the 1980s. While this idea was widely used to criticize neo-Darwinian evolutionary theory, critique does not yield an alternative framework that offers evolutionary explanations. In current Evo-devo the concept of constraint is of minor importance, whereas notions as evolvability are at the center of attention. The latter clearly defines an explanatory agenda for evolutionary research, so that one could view the historical shift from ‘developmental constraint’ (...) towards ‘evolvability’ as the move from a concept that is a mere tool of criticism to a concept that establishes a positive explanatory project. However, by taking a look at how the concept of constraint was employed in the 1980s, I argue that developmental constraint was not just seen as restricting possibilities (‘constraining’), but also as facilitating morphological change in several ways. Accounting for macroevolutionary transformation and the origin of novel form was an aim of these developmental approaches to evolution. Thus, the concept of developmental constraint was part of a positive explanatory agenda long before the advent of Evo-devo as a genuine scientific discipline. In the 1980s, despite the lack of a clear disciplinary identity, this concept coordinated research among paleontologists, morphologists, and developmentally inclined evolutionary biologists. I discuss the different functions that scientific concepts can have, highlighting that instead of classifying or explaining natural phenomena, concepts such as ‘developmental constraint’ and ‘evolvability’ are more important in setting explanatory agendas so as to provide intellectual coherence to scientific approaches. The essay concludes with a puzzle about how to conceptually distinguish evolvability and selection. (shrink)

This dissertation concerns the active role of the organism in evolutionary theory. In particular, it concerns how our conception of the relationship between organism and environment, and the nature of natural selection, influences the causal and explanatory role of organismic activity and behavior in evolutionary explanations. The overarching aim is to argue that the behaviors and activities of organisms can serve both as the explananda (that which is explained) and the explanantia (that which explains) in evolutionary explanations. I attempt to (...) achieve this aim by offering three central arguments. First, that the organism-environment relation is the ontologically basic unit of biology. A common way of conceiving the relationship between organism and environment is as a duality—as two causally independent systems that overlap through interaction. I think this is a mistake. There cannot be organisms without environments and vice versa. They are codependent and codetermined. Second, that natural selection is an ecological process. By this I mean that natural selection acts primarily on organism-environment interactions. It is only in virtue of organisms interacting with their environments that there can be fitness differences amongst individual organisms in a population. The ecological approach to natural selection also entails that the nature of the system(s) of inheritance involved in the reoccurrence of favorable organism-environment interactions is, in principle, immaterial to the process of selection. It only matters for selection that organism-environment interactions actually do reoccur in subsequent generations. Third, that niche construction theory—the most well-developed theoretical and conceptual framework for studying how the activities of organisms influences evolutionary dynamics—can be seen as fully a compatible and integrated part of evolutionary theory. Together, these three arguments constitute an overarching argument. Namely that we both can, and should, take organismic activity and behavior to be crucial explanatory elements in evolutionary theory. Throughout the dissertation I also show how these three arguments have consequences for other debates in the philosophy of evolutionary theory, such as the nature of evolutionary processes, the structure of selection-based explanations, the validity and utility of the proximate-ultimate distinction, and the nature of teleology in evolutionary systems. (shrink)

Resumen -/- El objetivo de este trabajo consiste en analizar las relaciones entre los modelos de optimalidad y la selección natural. Defenderemos que esas relaciones pueden dividirse en dos tipos, en tanto hay dos tipos de explicaciones seleccionistas, que llamaremos “históricas” y “ahistóricas”. Las explicaciones históricas revelan como una población dada adquiere un rasgo que es adaptativo en ese ambiente e involucran muchas generaciones, variación, etc. Las explicaciones ahistóricas, explican por qué, en determinado momento, ciertos tipos de organismos tienen un (...) mayor éxito reproductivo que otros. Mostraremos que los modelos de optimalidad pueden jugar un rol en la determinación del explanandum de las explicaciones histórica seleccionistas, esto es, que ayudan a reconocer qué rasgos son adaptativos. Por otra parte, mostramos que los modelos de optimalidad nos permiten determinar a veces la parte del explanans de las explicaciones ahistóricas (particularmente, el concepto de fitness). -/- Abstract -/- The goal of this paper is to analyze the relations between optimality models and natural selection. We contend that these relationships can be divided into two kinds, as there are two kinds of natural selection explanations, which we call “historical” and “ahistorical”. Historical explanations reveal how a given population acquires a trait which is adaptive in its environment, and involves many generations, variations, etc. Ahistorical ones, explain why, at a given moment, certain kinds of organisms have a greater reproductive success than others. We show that optimality models can play a role in determining the explanandum of historical selectionist explanations, that is, they help us to recognize which traits are adaptive. And, on the other hand, that optimality models sometimes allow us to determine part of the explanans of ahistorical explanations (particularly, the concept of fitness). (shrink)

Evo-Devo exhibits a plurality of scientific “cultures” of practice and theory. When are the cultures acting—individually or collectively—in ways that actually move research forward, empirically, theoretically, and ethically? When do they become imperialistic, in the sense of excluding and subordinating other cultures? This chapter identifies six cultures – three /styles/ (mathematical modeling, mechanism, and history) and three /paradigms/ (adaptationism, structuralism, and cladism). The key assumptions standing behind, under, or within each of these cultures are explored. Characterizing the internal structure of (...) the cultures is necessary for understanding how they collaborate or compete, and how they are fragmented or integrated, in the rich interdisciplinary /trading zone/ (Galison 1997) of Evo-Devo. Evo-Devo is an important example of how science can progress through a radical plurality of perspectives and cultures. (shrink)

According to conventional wisdom, local gauge symmetry is not a symmetry of nature, but an artifact of how our theories represent nature. But a study of the so-called theta-vacuum appears to refute this view. The ground state of a quantized non-Abelian Yang-Mills gauge theory is characterized by a real-valued, dimensionless parameter theta—a fundamental new constant of nature. The structure of this vacuum state is often said to arise from a degeneracy of the vacuum of the corresponding classical theory, which degeneracy (...) allegedly arises from the fact that “large” (but not “small”) local gauge transformations connect physically distinct states of zero field energy. If that is right, then some local gauge transformations do generate empirical symmetries. In defending conventional wisdom against this challenge I hope to clarify the meaning of empirical symmetry while deepening our understanding of gauge transformations. I distinguish empirical from theoretical symmetries. Using Galileo’s ship and Faraday’s cube as illustrations, I say when an empirical symmetry is implied by a theoretical symmetry. I explain how the theta-vacuum arises, and how “large” gauge transformations differ from “small” ones. I then present two analogies from elementary quantum mechanics. By applying my analysis of the relation between empirical and theoretical symmetries, I show which analogy faithfully portrays the character of the vacuum state of a classical non-Abelian Yang-Mills gauge theory. The upshot is that “large” as well as “small” gauge transformations are purely formal symmetries of non-Abelian Yang-Mills gauge theories, whether classical or quantized. It is still worth distinguishing between these kinds of symmetries. An analysis of gauge within the constrained-Hamiltonian formalism yields the result that “large” gauge transformations should not be classified as gauge transformations; indeed, nor should “global” gauge transformations. In a theory in which boundary conditions are modeled dynamically, “global” gauge transformations may be associated with physical symmetries, corresponding to translations of these extra dynamical variables. Such translations are symmetries if and only if charge is conserved. But it is hard to argue that these symmetries are empirical, and in any case they do not correspond to any constant phase change in a quantum state. (shrink)