The article presents the cognitive basis of the differentiation and definition of names in word classes. Cognitively analyzed substantivation, qualification and quantification and their circularity explain grammaticalization as a process. Definiteness as a categorical phenomenon of names is a syncretic grammaticalization of a cognitive-perspective minimum. Pronouns are not considered here, since their cognitive specificity does not contain the initiality of the nominative. Pronouns are the subject of a separate analysis in our other works.