What is the meaning of the togetherness of the perceiving mind, in that peculiar modification of perceiving which makes it perceive not a star but a tree, and the tree itself, is a problem for philosophy

Psychology is the science of the act of experiencing, and deals with the whole system of such acts as they make up mental life.

Curiosity begins as an act of tearing to pieces or analysis.

In the perception of a tree we can distinguish the act of experiencing, or perceiving, from the thing experienced, or perceived.

The interval between a cold expectation and a warm desire may be filled by expectations of varying degrees of warmth or by desires of varying degrees of coldness.

Thus the same object may supply a practical perception to one person and a speculative one to another, or the same person may perceive it partly practically and partly speculatively.

Such being the nature of mental life, the business of psychology is primarily to describe in detail the various forms which attention or conation assumes upon the different levels of that life.