This paper supplements an earlier one (Wassermann 1978b). Its views aim to reinforce those of Lewontin and other prominent evolutionists, but differ significantly from the opinions of some philosophers of science, notably Popper (1957) and Olding (1978). A basic distinction is made between 'laws' and 'theories of mechanisms'. The 'Theory of Evolution' is not characterized by laws, but is viewed here as a hypertheory which explains classifiable evolutionary phenomena in terms of subordinate classifiable theories of 'evolution-specific mechanisms' (ESMs), each of (...) which could apply to a host of species. Adaptations could result from ESMs that are rooted in molecular complementarities. The status of optimization theories that aim to predict best adapted states of organisms or populations is also discussed. (shrink)

We distinguish dynamical and statistical interpretations of evolutionary theory. We argue that only the statistical interpretation preserves the presumed relation between natural selection and drift. On these grounds we claim that the dynamical conception of evolutionary theory as a theory of forces is mistaken. Selection and drift are not forces. Nor do selection and drift explanations appeal to the (sub-population-level) causes of population level change. Instead they explain by appeal to the statistical structure of populations. We briefly discuss the implications (...) of the statistical interpretation of selection for various debates within the philosophy of biologythe `explananda of selection' debate and the `units of selection' debate. (shrink)

One approach to assess the explanatory power of natural selection is to ask what type of facts it can explain. The standard list of explananda includes facts like trait frequencies or the survival of particular organisms. Here, I argue that this list is incomplete: natural selection can also explain a specific kind of individual-level fact that involves traits. The ability of selection to explain this sort of fact vindicates the explanatory commitments of empirical studies on microevolution. Trait facts must be (...) distinguished from a closely related kind of fact, that is, the fact that a particular individual x has one trait rather than another. Whether or not selection can explain the latter type of fact is highly controversial. According to the so-called ‘Negative View’ it cannot be explained by selection. I defend the Negative View against Nanay’s objection. (shrink)

Recently, several philosophers have challenged the view that evolutionary theory is usefully understood by way of an analogy with Newtonian mechanics. Instead, they argue that evolutionary theory is merely a statistical theory. According to this alternate approach, natural selection and random genetic drift are not even causes, much less forces. I argue that, properly understood, the Newtonian analogy is unproblematic and illuminating. I defend the view that selection and drift are causes in part by attending to a pair of important (...) distinctions—that between process and product and that between natural selection and fitness. (shrink)

The thesis that natural selection explains the frequencies of traits in populations, but not why individual organisms have the traits tehy do, is here defended and elaborated. A general concept of ‘distributive explanation’ is discussed.

Evolutionary processes such as natural selection and random drift are commonly regarded as causes of population-level change. We respond to a recent challenge that drift and selection are best understood as statistical trends, not causes. Our reply appeals to manipulation as a strategy for uncovering causal relationships: if you can systematically manipulate variable A to bring about a change in variable B, then A is a cause of B. We argue that selection and drift can be systematically manipulated to produce (...) different kinds of population-level change. They should therefore be regarded as causes. (shrink)

I have recently argued that origin essentialism regarding individual organisms entails that natural selection does not explain why individual organisms have the traits that they do. This paper defends this and related theses against Mohan Matthen's recent objections.

Does natural selection explain why individual organisms have the traits that they do? According to "the Negative View," natural selection does not explain why any individual organism has the traits that it does. According to "the Positive View," natural selection at least sometimes does explain why an individual organism has the traits that it does. In this paper, I argue that recent arguments for the Positive View fail in virtue of running afoul of the doctrine of origin essentialism and I (...) demonstrate that other recent defenses of the Negative View depend upon my own for their plausibility. (shrink)

In this paper I argue against Sober's claim that natural selection does not explain the traits of individuals. Sober argues that natural selection only explains the distribution of traits in a population. My point is that the explanation of an individual's traits involves us in a description of the individual's ancestry, and in an explanation of the distribution of traits in that ancestral population. Thus Sober is wrong, natural selection is part of the explanation of the traits of individuals.

argue that natural selection does not explain the genotypic arid phenotypic properties of individuals. On this view, natural selection explains the adaptedness of individuals, not by explaining why the individuals that exist have the adaptations they do, but rather by explaining why the individuals that exist are the ones with those adaptations. This paper argues that this ‘Negative’ view of natural selection ignores the fact that natural selection is a cumulative selection process. So understood, it explains how the genetic sequences (...) that individuals inherit and that are responsible for their complex (and co-adapted) adaptations first arose in the gene-pool. (shrink)

The aim of this paper is to outline a typologyof selection processes, and show that differentsub-categories have different explanatorypower. The basis of this typology of selectionprocesses is argued to be the difference ofreplication processes involved in them. Inorder to show this, I argue that: 1.Replication is necessary for selection and 2.Different types of replication lead todifferent types of selection. Finally, it isargued that this typology is philosophicallysignificant, since it contrasts cases ofselection (on the basis of the replicationprocesses involved in them) (...) whereby selectioncauses adaptation – and, therefore, can beused in explanations of the (real or apparent)teleology of Nature – and cases in whichselection lacks such explanatory power. (shrink)

In this paper, I am clarifying and defending my argument in favor of the claim that cumulative selection can explain adaptation provided that the environmental resources are limited. Further, elaborate on what this limitation of environmental resources means and why it is relevant for the explanatory power of natural selection.

In this paper, I am clarifying and defending my argument in favor of the claim that cumulative selection can explain adaptation provided that the environmental resources are limited. Further, elaborate on what this limitation of environmental resources means and why it is relevant for the explanatory power of natural selection.

Two strong arguments have been given in favor of the claim that no selection process can play a role in explaining adaptations. According to the first argument, selection is a negative force; it may explain why the eliminated individuals are eliminated, but it does not explain why the ones that survived (or their offspring) have the traits they have. The second argument points out that the explanandum and the explanans are phenomena at different levels: selection is a population-level phenomenon, whereas (...) adaptation occurs on the individual level. Thus, selection can explain why individuals in a certain population have a certain trait, but it cannot explain why a certain indi- vidual has this trait. After pointing out that both arguments ignore the significance of the limitation of environmental resources, I will construe a positive argument for the claim that cumulative selection processes can, indeed, play a role in explaining adaptations. (shrink)

Recent discussions in the philosophy of biology have brought into question some fundamental assumptions regarding evolutionary processes, natural selection in particular. Some authors argue that natural selection is nothing but a population-level, statistical consequence of lower-level events (Matthen and Ariew [2002]; Walsh et al. [2002]). On this view, natural selection itself does not involve forces. Other authors reject this purely statistical, population-level account for an individual-level, causal account of natural selection (Bouchard and Rosenberg [2004]). I argue that each of these (...) positions is right in one way, but wrong in another; natural selection indeed takes place at the level of populations, but it is a causal process nonetheless. (shrink)

We have argued elsewhere that: (A) Natural selection is not a cause of evolution. (B) A resolution-of-forces (or vector addition) model does not provide us with a proper understanding of how natural selection combines with other evolutionary influences. These propositions have come in for criticism recently, and here we clarify and defend them. We do so within the broad framework of our own “hierarchical realization model” of how evolutionary influences combine.

Sound like a philosopher’s controversy? I think so. In ‘Evolution,’ I argued that Anti-Individualism was committed to a ‘highly metaphysical’ proposition at odds with the methodology of population genetics. This infelicity gave me reason for rejecting it. In his recent article, Pust takes issue with Neander and me. Until Pust wrote, Sober felt some small pressure from Individualism, and had shifted, albeit microscopically, toward it—he thought that on a very broad conception of causation, there might be some reason to think (...) that selection explains individual traits. He is now convinced that he was right all along. So we are back where we were a few years ago, though with new arguments on each side. Such is the nature of progress in philosophy. The purpose of this paper is to offer some refinements of Individualism. (shrink)

It has been claimed that certain forms of individual essentialism render the Theory of Natural Selection unable to explain why any given individual has the traits it does. Here, three reasons are offered why the Theory ought to ignore these forms of essentialism. First, the trait-distributions explained by population genetics supervene on individual-level causal links, and thus selection must have individual-level effects. Second, even if there are individuals that possess thick essences, they lie outside the domain of the Theory. Finally, (...) the contingency of sexual reproduction suggests that essentialism is misguided in this arena. 1 The problem 2 A reprise of the controversy 3 Enter individual essences 4 How can selection not have individual-level effects? 5 Why can't we get rid of essences we don't like? 6 Is sex necessary? (shrink)

natural selection may show why all (most, some) humans have an opposable thumb, but cannot show why any particular human has one, Karen Neander ([1995a], [1995b]) argues that this is false because natural selection is 'cumulative'. It is argued here, on grounds independent of its cumulativity, that selection can explain the characteristics of individual organisms subsequent to the event. The difference of opinion between Sober and his critics turns on an ontological dispute about how organisms are identified and individuated. The (...) assumption that Sober needs to make his point is extraneous to population genetics, and, for this reason, gratuitous. (shrink)

argues that when reproduction is sexual, natural selection can explain why individual organisms possess the traits they do. In stating his argument Matthen makes use of a conception of individual organisms as receptacles for collections of genes—a conception that cannot do the work Matthen requires of it. Either these receptacles are abstract objects, such as bare possibilities for organisms, or they are concrete. The first reading is too weak, since it allows selection to explain individual traits in both sexual and (...) asexual contexts. The only concrete entities we might think of as receptacles for collections of genes are male or female gametes. It is true that in the sexual context selection explains why an individual gamete combines with a second gamete of one type rather than another; however, this is not to say that selection explains why an individual organism has the traits it does. (shrink)

I advance a new theory of causal relevance, according to which causal claims convey information about conditional probability functions. This theory is motivated by the problem of disjunctive factors, which haunts existing probabilistic theories of causation. After some introductory remarks, I present in Section 3 a sketch of Eells's (1991) probabilistic theory of causation, which provides the framework for much of the discussion. Section 4 explains how the problem of disjunctive factors arises within this framework. After rejecting three proposed solutions, (...) I offer in Section 6 a new approach to causation that avoids the problem. Decision-theoretic considerations also support the new approach. Section 8 develops the consequences of the new theory for causal explanation. The resulting theory of causal explanation incorporates the new insights while respecting important work on scientific explanation by Salmon (1971), Railton (1981), and Humphreys (1989). My conclusions are enumerated in Section 9. (shrink)

The main argument of this paper is that an evaluation of the overall explanatory power of a theory is less problematic and more relevant as an assessment of the state of knowledge than evaluation of statistical explanations of single occurrences in terms of likelihoods that are assigned to explananda.

This paper examines the relationship between a family of concepts involving reliable correlation, and a family of concepts involving adaptation and biological function, as these concepts are used in the naturalistic semantic theory of Dretske's "Explaining Behavior." I argue that Dretske's attempt to marry correlation and function to produce representation fails, though aspects of his failure point the way forward to a better theory.

Can selection explain why individuals have the traits they do? This question has generated significant controversy. I will argue that the debate encompasses two separable aspects, to detrimental effect: (1) the role of selection in explaining the origin and evolution of biological traits and (2) the implications this may have for explaining why individuals have the traits they do. (1) can be settled on the basis of evolutionary theory while (2) requires additional, extra-scientific assumptions. By making a distinction between traits (...) affected by a single factor and traits affected by multiple factors I show that selection can, under certain conditions, help explain the origin of traits. Resolving the first aspect enables us to critically assess the various incompatible and independent philosophical commitments made within the second aspect of the debate. (shrink)

The historical origin and the experimental basis of the concept of physical determinism indicate that this basis was removed with the acceptance of the kinetic theory of matter, while its difficulties are increased by the admission that human nature, in its entirety, is a product of natural causation. An indeterministic view of causation has the advantages (a) of unifying the concept of natural law in different spheres of human experience and (b) of a greater generality, which precludes the acceptance of (...) the special case of completely deterministic causation, so long as this is an unproved assumption. It is not inconsistent with the orderliness of the world, or with the fruitful pursuit of natural knowledge. It enriches rather than weakens the concept of of causation. It possesses definite advantages with respect to the one-sidedness of human memory, and to the phenomena of aiming and striving observable in man and other animals. Among biological theories it appears to be most completely in harmony with the theory of natural selection, which in its statistical nature resembles the second law of thermo-dynamics. In an indeterministic world natural causation has a creative element, and science is interested in locating the original causes of effects of special interest, and not merely in pushing a chain of causation backwards ad infinitum. These contrasting tendencies are illustrated by a critique of the mutation theory, and by an attempt more closely to define the sense in which indeterministic causation should be thought of as creative. (shrink)

La autora presenta algunas criticas generales al proyecto de reducir las leyes causales a probabilidades. Además, muestra que las leyes causales son imprescindibles para poder diferenciar las strategias efectivas de las que no lo son y da un criterio para considerar cuando podemos deducir causalidad a través de datos estadísticos.

‘Natural selection’ is, it seems, an ambiguous term. It is sometimes held to denote a consequence of variation, heredity, and environment, while at other times as denoting a force that creates adaptations. I argue that the latter, the force interpretation, is a redundant notion of natural selection. I will point to difficulties in making sense of this linguistic practise, and argue that it is frequently at odds with standard interpretations of evolutionary theory. I provide examples to show this; one example (...) involving the relation between adaptations and other traits, and a second involving the relation between selection and drift. (shrink)

Proponents of two axioms of biological evolutionary theory have attempted to find justification by reference to nonequilibrium thermodynamics. One states that biological systems and their evolutionary diversification are physically improbable states and transitions, resulting from a selective process; the other asserts that there is an historically constrained inherent directionality in evolutionary dynamics, independent of natural selection, which exerts a self-organizing influence. The first, the Axiom of Improbability, is shown to be nonhistorical and thus, for a theory of change through time, (...) acausal. Its perception of the improbability of living states is at least partially an artifact of closed system thinking. The second, the Axiom of Historically Determined Inherent Directionality, is supported evidentially and has an explicit historical component. Historically constrained dynamic populations are inherently nonequilibrium systems. It is argued that living, evolving systems, when considered to be historically constrained nonequilibrium systems, do not appear improbable at all. Thus, the two axioms are not compatible. Instead, the Axiom of Improbability is considered to result from an unjustified attempt to extend the contingent proximal actions of natural selection into the area of historical, causal explanations. It is thus denied axiomatic status, and the effects of natural selection are subsumed as an additional level of constraint in an evolutionary theory derived from the Axiom of Historically Determined Inherent Directionality. (shrink)

The ultimate source of explanation in biology is the principle of natural selection. Natural selection means differential reproduction of genes and gene combinations. It is a mechanistic process which accounts for the existence in living organisms of end-directed structures and processes. It is argued that teleological explanations in biology are not only acceptable but indeed indispensable. There are at least three categories of biological phenomena where teleological explanations are appropriate.

In Chapter Five of The Mind Doesn’t Work That Way, Jerry Fodor argues that since it is likely that human minds evolved quickly as saltations rather than gradually as the product of an accumulation of small mutations, evolutionary psychologists are wrong to think that human minds are adaptations. I argue that Fodor’s requirement that adaptationism entails gradualism is wrongheaded. So, while evolutionary psychologists may be wrong to endorse gradualism—and I argue that they are wrong—it does not follow that they are (...) wrong to endorse an adaptationist explanation for how the human mind evolved. (shrink)

How do fitness and natural selection relate to other evolutionary factors like architectural constraint, mode of reproduction, and drift? In one way of thinking, drawn from Newtonian dynamics, fitness is one force driving evolutionary change and added to other factors. In another, drawn from statistical thermodynamics, it is a statistical trend that manifests itself in natural selection histories. It is argued that the first model is incoherent, the second appropriate; a hierarchical realization model is proposed as a basis for a (...) statistical treatment. It emerges that natural selection does not cause evolution; it just is evolution. The theory incorporates relations of statistical correlation, but not the kind of causation found in fundamental physical processes. (shrink)

“Probabilistic Causation” designates a group of theories that aim to characterize the relationship between cause and effect using the tools of probability theory. The central idea behind these theories is that causes change the probabilities of their effects. This article traces developments in probabilistic causation, including recent developments in causal modeling. A variety of issues within, and objections to, probabilistic theories of causation will also be discussed.

The neutral theory often is presented as a theory of "noise" or silent changes at an isolated "molecular level", relevant to marking the steady pace of divergence, but not to the origin of biological structure, function, or complexity. Nevertheless, precisely these issues can be addressed in neutral models, such as those elaborated here in regard to scrambled ciliate genes, gRNA-mediated RNA editing, the transition from self-splicing to spliceosomal splicing, and the retention of duplicate genes. All of these are instances of (...) a more general scheme of "constructive neutral evolution" that invokes biased variation, epistatic interactions, and excess capacities to account for a complex series of steps giving rise to novel structures or operations. The directional and constructive outcomes of these models are not due to neutral allele fixations per se, but to these other factors. Neutral models of this type may help to clarify the poorly understood role of non-selective factors in evolutionary innovation and directionality. (shrink)

This chapter surveys the philosophical problems raised by the two Darwinian claims of the existence of a Tree of a life, and the explanatory power of natural selection. It explores the specificity of explanations by natural selection, emphasizing the high context-dependency of any process of selection. Some consequences are drawn about the difficulty of those explanations to fit a nomological model of explanation, and the irreducibility of their historic-narrative dimension. The paper introduces to the debates about units of selection, stating (...) the compelling force of genic selectionnism but highlighting some critiques. Then it addresses the limits of selectionist explanations : the compared status of selection, drift and phylogenetic inertia are investigated, and the debates over adaptationism are presented, with the aim of defining the varieties of adaptationisms as research programs. In order to assess the scope of natural selection, the chapter addresses weak and strong challenges to the Synthetic theory of evolution, both from paleontology (punctuated equilibria, Gould’s contingency thesis) and evolutionary theory of development. We finally sketch some consequences of evolutionary theory concerning philosophical questions about human nature, on the basis of the hypothesis of the universality of selectionist explanations: this part deals mostly with epistemology and psychology. (shrink)

Some naturalistic theories of consciousness give an essential role to teleology.1 This teleology is said to arise due to natural selection. Thus it is claimed that only certain states, namely, those that have been selected for by evolutionary pro- cesses because they contribute to (or once contributed to) an organism’s fitness, are conscious states. These theories look as if they are assigning a creative role to natural selection. If a state is conscious only if it has been selected for, then (...) selec- tion appears to be able to create a new feature of states, namely, their conscious nature. Yet, intuitively, natural selection cannot create anything. Natural selec- tion chooses certain features that already exist and makes them more (or less) prevalent in a population, but it cannot bring features into existence itself. Natu- ral selection can select for conscious states, but it cannot create them. This con- clusion has recently been argued for by Steven Horst (1999). If it is right, then teleological theories of conscious states should be rejected. A state cannot become a conscious experience in virtue of having been selected for by evolu- tionary process. (shrink)

Chalmers and others have argued that physicalist microexplanation is incapable of solving the ‘hard problem’ of consciousness. This article examines whether evolutionary accounts of the mind, such as those developed by Millikan, Dretske and Flanagan, can add anything to make up for the possible short falls of more reductionist accounts. I argue that they cannot, because evolutionary accounts explain by appeal to a selectional history that only comes into the picture if consciousness can first arise due to spontaneous mutation in (...) some individual organism, and explaining this emergence of consciousness from DNA and embryology calls for precisely the kind of structurally-based supervenience account that Chalmers et al. have objected to. Not only does an evolutionary account not succeed where a reductionist account fails; the evolutionary account presupposes the possibility of a reductionist account. (shrink)