Desire then is the invasion of the whole self by the wish, which, as it invades, sets going more and more of the psychical processes; but at the same time, so long as it remains desire, does not succeed in getting possession of the self.

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.

The mental act of sensation which issues in reflex movement is so simple as to defy analysis.

An object is not first imagined or thought about and then expected or willed, but in being actively expected it is imagined as future and in being willed it is thought.

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

The perceptive act is a reaction of the mind upon the object of which it is the perception.

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