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