This chapter offers arguments in support of categorialism and then inquires whether these arguments can be extended from the domain of singular thought to that of singular linguistic reference. It inquires whether it can reasonably be contended that a speaker cannot successfully refer to an object by means of a proper name unless he or she grasps, at least implicitly, that the name's referent falls under a certain categorial concept, which supplies a criterion of identity for the referent. The chapter talks interchangeably of terms and concepts. Sortal terms fall into hierarchies of subsumption. The chapter presents a note on criteria of identity and sortal persistence conditions. The notion of individuation with which the chapter is chiefly concerned at present is a purely cognitive notion. Categorialism is a thesis about singular thought, not about linguistic reference.