Nay, it may be questioned how far it is either psychologically or logically possible to turn general scepticism into a coherent doctrine.
What Cousin finds psychologically in the individual consciousness, he finds also spontaneously expressed in the common sense or universal experience of humanity.
A judgment which is not prompted by motives and inspired by interest, which has not for its aim the satisfaction of a cognitive purpose, is psychologically impossible, and it is, therefore, mistaken to construct a logic which abstracts from all these facts.
Hence, our evidence for serpent-cults everywhere represents varying stages in the historical development of a few related fundamental ideas which are psychologically explicable; and it is impossible to deal with the subject geographically or historically.
As a branch of mathematics, arithmetic may be treated logically, psychologically, or historically.