What directs itself, knows.
For unless someone is aware of his own self, he cannot direct it. Only a knower, therefore, can direct his self, properly speaking.
The above argument suffices but there are many others taken apart from proper cause: praise and blame, awareness and intention, our interior awareness that our knowledge is essentially related to our self direction, etc.
So what does not know, and has direction to something, is being directed by another.
But all that is moving has direction to something.
So all motion depends upon intelligence, for what is by another is properly from what is by itself.
Again, to be by another is a way of being after, what is by itself is before. To think that everything is by another is to think that everything is after an after an after.
Or again it is a failure to understand basic truths about relative terms. Relatives properly speaking cannot exist without their correlatives. To think all could be after of from another would be like thinking there could be all beneath and nothing above, all sons in a world where there never were fathers.
The first trace of actuality, motion, presupposes and depends upon that highest actuality, the immobile and intelligent.