since ideas arise, so to speak, by the mind’s inertia and conceptions of things by its activity. Ideas are mental sediment; conceived things are mental growths. A concretion in discourse occurs by repetition and mere emphasis on a datum, but a concretion in existence requires a synthesis of disparate elements and relations. An idea is nothing but a sensation apperceived and rendered cognitive, so that it envisages its own recognised character as its object and ideal: yellowness is only some sensation of yellow raised to the cognitive power and employed as the symbol for its own specific essence. It is consequently capable of entering as a term into rational discourse and of becoming the subject or predicate of propositions eternally valid. A thing, on the contrary, is discovered only when the order and grouping of such recurring essences can be observed, and when various themes and strains of experience are woven together into elaborate progressive harmonies. When consciousness first becomes cognitive it frames ideas; but when it becomes cognitive of causes, that is, when it becomes practical, it perceives things.
Concretions of qualities recurrent in time and concretions of qualities associated in existence are alike involved in daily life and inextricably ingrown into the structure of reason. In consciousness and for logic, association by similarity, with its aggregations and identifications of recurrences in time, is fundamental rather than association