The sensory acts are accordingly distinguished by their objects.

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.

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

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.

It is more difficult to designate this form of conation on its practical side by a satisfactory name.

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