This book is a critical survey of and guidebook to the literature on biological functions. It ties in with current debates and developments, and at the same time, it looks back on the state of discourse in naturalized teleology prior to the 1970s. It also presents three significant new proposals. First, it describes the generalized selected effects theory, which is one version of the selected effects theory, maintaining that the function of a trait consists in the activity that led to (...) its differential persistence or reproduction in a population, and not merely its differential reproduction. Secondly, it advances “within-discipline pluralism” (as opposed to between-discipline pluralism) a new form of function pluralism, which emphasizes the coexistence of function concepts within diverse biological sub-disciplines. Lastly, it provides a critical assessment of recent alternatives to the selected effects theory of function, namely, the weak etiological theory and the systems-theoretic theory. The book argues that, to the extent that functions purport to offer causal explanations for the existence of a trait, there are no viable alternatives to the selected effects view. -/- The debate about biological functions is still as relevant and important to biology and philosophy as it ever was. Recent controversies surrounding the ENCODE Project Consortium in genetics, the nature of psychiatric classification, and the value of ecological restoration, all point to the continuing relevance to biology of philosophical discussion about the nature of functions. In philosophy, ongoing debates about the nature of biological information, intentionality, health and disease, mechanism, and even biological trait classification, are closely related to debates about biological functions. (shrink)

I defend the historical definition of "function" originally given in my Language, Thought and Other Biological Categories (1984a). The definition was not offered in the spirit of conceptual analysis but is more akin to a theoretical definition of "function". A major theme is that nonhistorical analyses of "function" fail to deal adequately with items that are not capable of performing their functions.

Finding a naturalistic account of biological function is important both for making sense of the way functions are talked about in biology and medicine and for the project in the philosophy of mind of naturalising mental content via teleosemantics. The selected effects theory accounts for the proper functions of traits in terms of their selectional history, and is widely considered to be the most promising approach to naturalising biological functions. However, new challenges to the selected effects account have recently emerged. (...) Matthewson ( 2020 ) argues that natural selection comes in degrees and that on the face of it biological function does not, suggesting that analysing the latter in terms of the former is therefore problematic. Christie et al. (forthcoming) argue that the selected effects account of function does not fit with biologically detailed accounts of actual selection processes, in that it focuses on the functions of traits of individuals rather than the frequency of traits in populations and does not generate accurate selectional explanations in cases in which there is not a uniform selective environment. This paper defends the selected effects account against these challenges, arguing that a viable response to Matthewson is that _any_ degree of selection suffices to confer proper functions, and that Christie et al. mischaracterise the aims and assumptions of the selected effects account. (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.

In this paper I defend an etiological theory of biological functions (according to which the proper function of a trait is the effect for which it was selected by natural selection) against three objections which have been influential. I argue, contrary to Millikan, that it is wrong to base our defense of the theory on a rejection of conceptual analysis, for conceptual analysis does have an important role in philosophy of science. I also argue that biology requires a normative notion (...) of a "proper function", and that a normative notion is not ahistorical. (shrink)

The etiological approach to ‘proper functions’ in biology can be strengthened by relating it to Robert Cummins' general treatment of function ascription. The proper functions of a biological trait are the functions it is assigned in a Cummins-style functional explanation of the fitness of ancestors. These functions figure in selective explanations of the trait. It is also argued that some recent etiological theories include inaccurate accounts of selective explanation in biology. Finally, a generalization of the notion of selective explanation allows (...) an analysis of the proper functions of human artifacts. (shrink)

Biological functions are dispositions or effects a trait has which explain the recent maintenance of the trait under natural selection. This is the "modern history" approach to functions. The approach is historical because to ascribe a function is to make a claim about the past, but the relevant past is the recent past; modern history rather than ancient.

The success of a piece of behaviour is often explained by its being caused by a true representation (similarly, failure falsity). In some simple organisms, success is just survival and reproduction. Scientists explain why a piece of behaviour helped the organism to survive and reproduce by adverting to the behaviour’s having been caused by a true representation. That usage should, if possible, be vindicated by an adequate naturalistic theory of content. Teleosemantics cannot do so, when it is applied to simple (...) representing systems (Godfrey-Smith 1996). Here it is argued that the teleosemantic approach to content should therefore be modified, not abandoned, at least for simple representing systems. The new ‘infotel-semantics’ adds an input condition to the output condition offered by teleosemantics, recognising that it is constitutive of content in a simple representing system that the tokening of a representation should correlate probabilistically with the obtaining of its specific evolutionary success condition. (shrink)

The selected effects or ‘etiological’ theory of Proper function is a naturalistic and realist account of biological teleology. It is used to analyse normativity in philosophy of language, philosophy of mind, philosophy of medicine, and elsewhere. The theory has been developed with a simple and intuitive view of natural selection. Traits are selected because of their positive effects on the fitness of the organisms that have them. These ‘selected effects’ are the Proper functions of the traits. Proponents argue that this (...) analysis of biological teleology has the unique advantage that the selected effect function of a trait is also a causal explanation of the trait: the trait exists because it performs this function. We show, however, that selected effect functions as currently defined explain the existence of traits only under highly restrictive assumptions about evolutionary dynamics. In many common scenarios in which traits evolve by natural selection, selected effect functions do not explain those traits. This is because definitions of selected effect function extract from any evolutionary scenario only the information that would be explanatorily relevant in the simple evolutionary scenario implicit in those definitions. When applied to more complex scenarios, selected effect functions omit the key information that is explanatorily relevant in those scenarios. The assumptions required for selected effect functions to be explanatory are particularly unlikely to hold in the domain that its proponents care most about—the evolution of representation. A more adequate selected effects theory of Proper functions may be possible, but will require much greater attention to the structure of actual evolutionary explanations. (shrink)

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)

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.