Proposition Xvii.
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Proclus and Taylor, Thomas
PROPOSITION XVII.
Every thing which moves itself primarily, is convertive to itself.
For if it moves itself, and its motive energy is directed to itself, that which moves, and that which is moved are at the same time one. For it either moves in a part but is moved in a part, or the whole moves and is moved, [or the whole moves, but a part is moved, or[217]] the contrary. But if one part indeed, is that which moves, and another part is that which is moved, it will not be essentially self-motive, since it will consist of things which are not self-motive, but which appear indeed to be so, yet are not so essentially.
If however, the whole moves, but the part is moved, or the contrary, there will be a certain part in both which according to one, moves and at the same time is moved.[218] And this is that which is primarily self-motive. If however, one and the same thing moves and is moved, it will have the energy of moving to itself, being motive of itself. But it is converted to that towards which it energizes. Every thing therefore which primarily moves itself, is converted to itself.