Online research in philosophy

The specialization of visual function within biological function is reason for introducing “homology thinking” into explanations of the visual system. It is argued that such specialization arises when organisms evolve by differentiation from their predecessors. Thus, it is essentially historical, and visual function should be regarded as a lineage property. The colour vision of birds and mammals do not function the same way as one another, on this account, because each is an adaptation to special needs of the visual functions of predecessors—very different kinds of predecessors in each case. Thus, history underlies function. We also see how homology thinking figures in the hierarchical classification of visual systems, and how it supports the explanation of visual function by functional role analysis.

Teleological theories of content are thought to suffer from two related difficulties. According to the problem of indeterminacy, biological function is indeterminate in the sense that, in the case of two competing interpretations of the function of an evolved mechanism, there is often no fact of the matter capable of determining which function is the correct one. Therefore, any attempts to construct content out of biological function entail the indeterminacy of content. According to the problem of transparency, statements of biological function are transparent in that a statement of the form 'the function of evolved mechanism M is to represent Fs' can be substituted salva veritate by a statement of the form 'the function of evolved mechanism M is to represent Gs' provided that the statement 'F iff G' is counterfactual supporting. Therefore, any attempt to construct content out of biological function must fail to capture the intensionality of psychological ascriptions. This paper argues that the teleological account is undermined by neither of these problems. Failure to appreciate this point stems from a conflation of two types of proper function - organismic and algorithmic - possessed by an evolved mechanism. These functions underwrite attributions of content to distinct objects. The algorithmic proper function of a mechanism underwrites attributions of content to the mechanism itself, while the organismic proper function of a mechanism underwrites attribution of content to the organism that possesses the mechanism. However the problems of indeterminacy and transparency arise only if the attributions of content attach to the same object.

In virtue of what does a representational state have the content it does? Several philosophers have recently proposed that a representational state gets its content from its biological function. After explaining the sense of biological function used in these views, I criticise the proposal. I argue that biological function only determines representational content up to extensional equivalence. I maintain that this holds even if biological function is defined in terms of an intensional notion like Sober's "selection for".

Recently something close to a consensus about the best way to naturalize the notion of biological function appears to be emerging. Nonetheless, teleological notions in biology remain controversial. In this paper we provide a naturalistic analysis for the notion of natural design. Many authors assume that natural design should be assimilated directly to function. Others find the notion problematic because it suggests that evolution is a directed process. We argue that both of these views are mistaken. Our naturalistic account does not simply equate design with function. We argue that the distinction between function and design is important for understanding the evolution of the physical and behavioral traits of organisms.

“Functional homology” appears regularly in different areas of biological research and yet it is apparently a contradiction in terms—homology concerns identity of structure regardless of form and function. I argue that despite this conceptual tension there is a legitimate conception of ‘homology of function’, which can be recovered by utilizing a distinction from pre-Darwinian physiology (use versus activity) to identify an appropriate meaning of ‘function’. This account is directly applicable to molecular developmental biology and shares a connection to the theme of hierarchy in homology. I situate ‘homology of function’ within existing definitions and criteria for structural assessments of homology, and introduce a criterion of ‘organization’ for judging function homologues, which focuses on hierarchically interconnected interdependencies (similar to relative position and connection for skeletal elements in structural homology). This analysis of biological concepts has at least three broad philosophical consequences: (1) it provides the grounds for the study of behavior and psychological categories as homologues; (2) it demonstrates that philosophers who take selected effect function as primary effectively ignore large portions of comparative, structural, and experimental research, thereby misconstruing biological reasoning and knowledge; and, (3) it underwrites causal generalizations, which illuminates inferences made from model organisms in experimental biology.

In the biological realm, a complete explanation of a trait seems to include an explanation in terms of function. It is natural to ask of some trait, "What is its function?" or "What purpose in the organism does the particular trait serve?" or "What is the goal of its activity?" There are several views concerning the appropriate definition of function for biological matters. Two popular views of function with respect to living things are Cummins' organizational account and the Griffiths/Godfrey-Smith modern history account. Whereas Cummins argues that a trait functions so as to contribute to the general organization of some organism's present structure, Griffiths, and Godfrey-Smith argue that a trait functions because of its fitness with respect to the organism's recent evolutionary history. In this paper, I show how these accounts can be made compatible and compliment one another. Given that structure, organization, operational flexibility, function, and evolutionary history are all factors to be considered in an organism's makeup, we should expect that the traits of an organism function the way they do because such traits presently contribute to the overall organization of the organism (Cummins) as well as were selected for in the organism's species' recent ancestry (Griffiths/Godfrey-Smith).

According to historical theories of biological function, a trait's function is determined by natural selection in the past. I argue that, in addition to historical functions, ahistorical functions ought to be recognized. I propose a theory of biological function which accommodates both. The function of a trait is the way it contributes to fitness and fitness can only be determined relative to a selective regime. Therefore, the function of a trait can only be specified relative to a selective regime. Apart from its desirable pluralism, only this view of relational function can support the function/accident and function/malfunction distinctions commonly thought to be part of the concept of function. Furthermore, only relational function correctly characterizes the explanatory consequences of function attributions in evolutionary biology.

Many philosophers believe that 1) most uses of functional language in biology make implicit reference to natural selection and 2) the fundamental way in which biologists identify parts and processes in organisms is by their selected function(s). Both these claims are mistaken. Much functional language in biology refers to actual causal roles, and if this were not so, biology would be impossible. The extensive biological literature on the ‘character concept’ focuses on another principle of biological identity, namely homology. I outline some of this work and use it to refute philosophical arguments for the importance and ubiquity of classification by adaptive function.

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: (1) function as (mere) activity, (2) function as biological role, (3) function as biological advantage, and (4) function as selected effect. Notion (1) refers to what an item does by itself; (2) refers to the contribution of an item or activity to a complex activity or capacity of an organism; (3) refers to the value for the organism of an item having a certain character rather than another; (4) 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.