Generalisation is the act of comprehending under a general name a number of objects which agree in one or more points. These points are specially attended to by the process of Abstraction (q.v.), and are indicated by the common name. The result of generalisation is a common name or general term, which stands for the many objects in so far only as they all agree. This process is closely akin to classification and to definition; and the higher kind of generalisation is Induction (q.v.).
In logic the genus is a higher class which includes a lower, the lower one being the Species; but the distinction is only relative. That which is a genus in relation to its species is itself a species in regard to a higher genus. The genus has the larger Extension (q.v.), the species the larger intension. For the great question as to whether the genera and species have a real existence, see NOMINALISM. For genus in natural history, see GENUS.