Abstract: The theory of concepts advanced in the dissertation aims at accounting for a) how a concept makes successful practice possible, and b) how a scientific concept can be subject to rational change in the course of history. Traditional accounts in the philosophy of science have usually studied concepts in terms only of their reference; their concern is to establish a stability of reference in order to address the incommensurability problem. My discussion, in contrast, suggests that each scientific concept consists of three components of content: 1) reference, 2) inferential role, and 3) the epistemic goal pursued with the concept's use. I argue that in the course of history a concept can change in any of these three components, and that change in one component—including change of reference—can be accounted for as being rational relative to other components, in particular a concept's epistemic goal. This semantic framework is applied to two cases from the history of biology: the homology concept as used in 19th and 20th century biology, and the gene concept as used in different parts of the 20th century. The homology case study argues that the advent of Darwinian evolutionary theory, despite introducing a new definition of homology, did not bring about a new homology concept (distinct from the pre-Darwinian concept) in the 19th century. Nowadays, however, distinct homology concepts are used in systematics/evolutionary biology, in evolutionary developmental biology, and in molecular biology. The emergence of these different homology concepts is explained as occurring in a rational fashion. The gene case study argues that conceptual progress occurred with the transition from the classical to the molecular gene concept, despite a change in reference. In the last two decades, change occurred internal to the molecular gene concept, so that nowadays this concept's usage and reference varies from context to context. I argue that this situation emerged rationally and that the current variation in usage and reference is conducive to biological practice. The dissertation uses ideas and methodological tools from the philosophy of mind and language, the philosophy of science, the history of science, and the psychology of concepts

Abstract: It is commonplace in cognitive science that concepts are individuated in terms of the roles they play in the cognitive lives of thinkers, a view that Jerry Fodor has recently been dubbed ‘Concept Pragmatism’. Quinean critics of Pragmatism have long argued that it founders on its commitment to the analytic/synthetic distinction, since without such a distinction there is plausibly no way to distinguish constitutive from non-constitutive roles in cognition. This paper considers Fodor’s empirical arguments against analyticity, and in particular his arguments against lexical decomposition and definitions, and argues that Concept Pragmatists have two viable options with respect to them. First, Concept Pragmatists can confront them head-on, and argue that they do not show that lexical items are semantically primitive or that lexical concepts are internally unstructured. Second, Pragmatists may accept that these arguments show that lexical concepts are atomic, but insist that this need not entail that Pragmatism is false. For there is a viable version of Concept Pragmatism that does not take lexical items to be semantically structured or lexical concepts to be internally structured. Adopting a version of Pragmatism that takes meaning relations to be specified by inference rules, or meaning postulates, allows one to accept the empirical arguments in favor of Concept Atomism, while at the same time deny that such arguments show that there are no analyticities. The paper concludes by responding to Fodor’s recent objection that such a version of Concept Pragmatism has unhappy consequences concerning the relation between concept constitution and concept possession