ONE SPECIAL KIND OF CONCEPT

One use of the word “concept” equates a concept with whatever it is one has to learn in order to use a certain word correctly. So we can talk of the concept or and the concept of and the concepts hurrah, the, because, necessarily, ouch, good, true, two, exists, is – and so forth. We can talk that way, but then we should remember Wittgenstein's warning: “Think of the tools in a toolbox: there is a hammer, pliers, a saw, a screwdriver, a glue pot, nails and screws – The functions of words are as diverse as the functions of these objects” (1953, Section 11). Given this broad usage of “concept,” there will be little or nothing in common about any two of these various concepts. We mustn't expect a theory of how the tape measure works to double as a theory of how the glue works.

In this book, I propose a thesis about the nature of one and only one kind of concept, namely, concepts of what (with a respectful nod to Aristotle) I call “substances.” Paradigmatic substances, in my sense, are individuals (Mama, The Empire State Building), stuffs (gold, milk), and natural kinds (mouse, geode). The core of the theory is not, however, about grasp of the use of words for substances (although I will get to that). Rather, the core belongs to the general theory of cognition, in exactly the same way that theories of perception do. Substance concepts are primarily things we use to think with rather than to talk with.