On The Soul   

Further, if the natural movement of the soul be upward, the soul

must be fire; if downward, it must be earth; for upward and downward

movements are the definitory characteristics of these bodies. The same

reasoning applies to the intermediate movements, termini, and

bodies. Further, since the soul is observed to originate movement in

the body, it is reasonable to suppose that it transmits to the body

the movements by which it itself is moved, and so, reversing the

order, we may infer from the movements of the body back to similar

movements of the soul. Now the body is moved from place to place

with movements of locomotion. Hence it would follow that the soul

too must in accordance with the body change either its place as a

whole or the relative places of its parts. This carries with it the

possibility that the soul might even quit its body and re-enter it,

and with this would be involved the possibility of a resurrection of

animals from the dead. But, it may be contended, the soul can be moved

indirectly by something else; for an animal can be pushed out of its

course. Yes, but that to whose essence belongs the power of being

moved by itself, cannot be moved by something else except

incidentally, just as what is good by or in itself cannot owe its

goodness to something external to it or to some end to which it is a

means.

If the soul is moved, the most probable view is that what moves it

is sensible things.

We must note also that, if the soul moves itself, it must be the

mover itself that is moved, so that it follows that if movement is

in every case a displacement of that which is in movement, in that

respect in which it is said to be moved, the movement of the soul must

be a departure from its essential nature, at least if its

self-movement is essential to it, not incidental.

Some go so far as to hold that the movements which the soul

imparts to the body in which it is are the same in kind as those

with which it itself is moved. An example of this is Democritus, who