As mere subjective function, which it is to the psychologist, it is best spoken of by an unambiguous name, and for this there seems none better than Intellection.
And what Spinoza has to say of the requisites of definition and the marks of intellection makes it clear that insight comes with coherence, and that the work of method on the " inductive " side is by means of the unravelling of all that makes for artificial limitation to lay bare what can then be seen to exhibit nexus in the one great system.
We may then say that psychology is occupied with the natural function of Intellection, seeking to discover its laws and distinguishing its various modes (perception, representative imagination, conception, &c.) according to the various circumstances in which the laws are found at work.
He defined his problem as the quid juris or the question of the validity of knowledge, not its quid facti or the laws of the empirical genesis and evolution of intellection (to use Croom Robertson's phraseology).