Christopher Peacocke

The principal thesis of A Study of Concepts is that a concept is individuated by its possession condition. Concepts are here understood to be sliced as finely as epistemic possibility. So now and 6 o’clock are different concepts, even if, in context, they pick out the same time; likewise for the observational concept circular and the complex concept locus of coplanar points equidistant from a given point. In the simplest cases, a possession condition is stated by giving a true, individuating statement of the form.

Only computational explanations of a content‐involving sort can answer certain ‘how’‐questions; can support content‐involving counterfactuals; and have the generality characteristic of psychological explanations. Purely formal characteriza‐tions of computations have none of these properties, and do not determine content. These points apply not only to psychological explanation, but to Turing machines themselves. Computational explanations which involve content are not opposed to naturalism. They are also required if we are to explain the content‐involving properties of mental states.

This paper has five theses, which are intended to address the claims in Jerry Fodor's paper. (1) The question arises of the relation between the philosophical theory of concepts and epistemology. Neither is explanatorily prior to the other. Rather, each relies implicitly on distinctions drawn from the other. To explain what makes something knowledge, we need distinctions drawn from the theory of concepts. To explain the attitudes mentioned in a theory of concepts, we need to use the notion of knowledge. (2) Concepts can have a normative dimension without their nature being interpretation‐dependent, and without their nature being mind‐dependent. The normative dimension traces back instead to the role of truth as a constitutive aim of judgement. (3) Conceptual combination is to be explained at the level of reference and semantic value. When we respect this fact, there is no difficulty in explaining compositionality for epistemically‐constrained concepts. (4) Epistemically‐constrained theories of concepts are committed to the applicability of the notion of the a priori. They are not committed to the applicability of the notion of analyticity, where this is construed as truth purely in virtue of meaning or the identity of concepts. (5) Possession of a concept has causal‐explanatory powers, whether given by a possession condition in the form presented in A Study of Concepts, or by possession of an implicit conception. A possession‐condition theory of concepts need not be a form of dispositionalism.

This paper is built around a single, simple idea. It is widely agreed that there is a distinctive kind of awareness each of us has of his own bodily actions. This action-awareness is different from any perceptual awareness a subject may have of his own actions; it can exist in the absence of such perceptual awareness. The single, simple idea around which this paper is built is that the distinctive awareness that subjects have of their own mental actions is a form of action-awareness. Subjects’ awareness of their own mental actions is a species of the same genus that also includes the distinctive awareness of bodily actions. More specifically, I claim

It seems to be an obvious truth that There could be something that doesn't actually exist.That is, it seems to be obiously true that ◊∃×).It is sufficient for the truth of that there could be more people, or trees, or cars, than there actually are. It is also sufficient for the truth of that there could be some pepole, or trees, or cars that are distinct from all those that actually exist. Do and suchlike statements involve a commitment to possibilia, to things that possibly exist, but do not actually exist? If not, why not? And if so, what is the nature of the possibilia to which and its ilk commit us? These simple little questions are at the tip of an iceberg.

There are issues in the theory of concepts about which A Study of Concepts could have said more. There are also some issues about which it would have done well to say something different. The commentators in this symposium have successfully identified a series of issues of one or other of these two kinds, and I am very grateful for their thought and detailed attention. I have learned from reflection on their comments, and I take this opportunity to try to carry the discussion forward by addressing a range issues underdeveloped in A Study of Concepts. Georges Rey raises global questions about the project of SoC. Answerability, Quinean challenges and the relations between my approach and covariation or ‘locking’ theories are amongst the problems he raises. The comments of David Papineau are at an intermediate level of generality. He poses questions about the subject-matter of a theory of concepts, and rejects my critique of teleological theories of content. He is also dissatisfied with my account of the relations between actual thought and the normative properties of concepts. I will consider that issue at some length. Jane Heal considers my elaboration of the approach for a specific concept, that of belief. I will take the topics in that order.