Peirce’s theory of categorization is reconstructed and shown that the canonical form of the categories proposed by him are Firstness, Secondness, Thirdness. The related categories of Tychism, Synechism and Agapism are also discussed and shown several problems. In particular, I discuss about the sense in which we can speak of ultimate and basic categories, the different forms of relations, the different kinds of causes, the principle of habit-forming, the possible evolution of laws, the role of representation in our dealing with (...) reality. (shrink)