In considering the cognitive powers of soul (what are now called mind or consciousness) Aristotle raises an important question:
Again, which ought we to investigate first, these parts or their functions, mind or thinking, the faculty or the act of sensation, and so on? If the investigation of the functions precedes that of the parts, the further question suggests itself: ought we not before either to consider the correlative objects, e.g. of sense or thought?
Aristotle’s answer comes in the next book:
If we are to express what each is, viz. what the thinking power is, or the perceptive, or the nutritive, we must go farther back and first give an account of thinking or perceiving, for in the order of investigation the question of what an agent does precedes the question, what enables it to do what it does. If this is correct, we must on the same ground go yet another step farther back and have some clear view of the objects of each; thus we must start with these objects, e.g. with food, with the sensible object, or with what is intelligible.
The axiom that Aristotle is working from is the intelligible priority of act, or, alternatively, the derivative intelligibility of possibility and potency, i.e. possibility only gets a logos relative to what arises from it. Cognitive powers are only intelligible relative to objects. This is why STA defines knowledge by starting with its object, specifying that the object is what is apt to be in another. Mind, therefore, first arises as the “other” of its cognitive world.
Descartes reverses all of this, or perhaps puts an interesting spin on it. For him, mind or consciousness becomes self-luminous and gets an intelligible priority to its objects. The power or faculty is seen as more fundamental and “farther back” in causality than its object.
This Cartesian move is part of a much larger class of arguments that (usually tacitly) attempt to derive actuality from potency, whether David of Dinant’s claim that God is prime matter or the Democratian/Evolutionist/multiverse theory belief that explaining any actual thing is just a matter of making a large enough domain of probabilities so as to diminish our surprise in the fact that it exists.*
*With infinite trails, all outcomes happen infinitely and so we have no right to be surprised by any outcome. Of course it happens. But all this means is that we can’t confuse explaining something with lacking surprise that it exists.