Repetition and variation of sense-impressions stimulates and sharpens attention. Pleasure or pain evokes interest and the intellect concentrates on part of the sensuous experience, and the process of abstraction begins. Certain attributes are laid hold of, to the omission of others. Comparison and discrimination are also called into action, and the more accurate and perfect elaboration of concepts now proceeds rapidly. The notions of substance and accidents, of whole and parts, of permanent and changing, are evolved with increasing distinctness.
Generalization follows quickly upon abstraction.
When an attribute or an object has been singled out and recognized as a thing distinct from its surroundings, an act of reflection renders the mind aware of the object as capable of indefinite realization and multiplication in other circumstances, and we have now the formally reflex universal idea. The further activity of the intellect is fundamentally the same in kind, comparing, identifying, or discriminating. The activity of ratiocination is merely reiteration of the judicial activity. The final stage in the elaboration of a concept is reached when it is embodied for further use in a general name. Words presuppose intellectual ideas, but register them and render them permanent.