Difference between causation, excitation and motivation, to use the terms of Schopenhauer:

Causation is, for instance, in us, in the movement along the nerves; excitation in the alteration these make; and motivation in the action born of the excitation.

Thus excitation is the change of a mov[emen]t of transference to a movement of alteration. Motivation appears to be the passing of a movement of alteration into a movement of transference.

But what is a movement of alteration? Is it ideal? It is natural that anything occupying time should alter, and that all things in space should be in movement; these things are contained in the nature of the notions of time and of space.

How can this be by the side of the theory that excitation is the emotion, which is of the nature of idea = thing?

Everything is bound to be in time and in space, since these ideas exist. Therefore there cannot be any movement of alteration only, it must be accompanied by some movement of transference. Now, mo[vemen]t of transference is of 2 kinds: mov[emen]t of continuation and mov[emen]t of vibration, that is to say, mov[emen]t without return and mov[emen]t with return. Alteration itself is not material, it is a purely ideal phenomenon; the material correspondent is a movement of some kind.

The question then is made simpler; it becomes a question of transmission of movement purely of transference, all in the material plane.