The notion of a category appears to have suffered a tragic decline. It started life as a basic concept of the grand metaphysical tradition of philosophy. By the heyday of linguistic philosophy it had been reduced to a tool of a purely negative project, namely the critique of certain philosophical doctrines or questions as based on linguistic mistakes. Later even its negative potential was questioned and it became common opinion that no coherent doctrine of categories can be devised. Later still, even these failures and disappointments were almost forgotten and the notion of categories seemed relevant merely to scholars of Aristotle and Kant.