Thinking makes itself into passive understanding, that is, into what is for it the objective; and thus it here becomes plain to what extent the dictum _nihil est in intellectu quod non fuerit in sensu_ expresses Aristotle’s meaning. Aristotle, raising difficulties, goes on to ask, “If reason is simple and unaffected by impressions, and has nothing in common with other objects, how can it think, since thinking is certainly a state of receptivity?” That is to say, in thinking there is a reference to an object distinct from itself. “For it is when two objects have something in common that the one appears to produce and the other to receive an impression. There is a further difficulty, whether understanding can itself be the object of thought. In that case understanding would either be inherent in other things—unless it is the object of thought in a different sense from that in which other things are so, but there is only one sense in which things can be objects of thought—or, on the other hand, it would have something compounded with it, making it an object of thought as other things are. Now it has been already said that passivity is so determined that understanding is in potentiality all that thought is exercised on: but at the same time it is in actuality nothing before the exercise of thought.” That is to say, thought is implicitly the content of the object of what is thought, and in coming into existence it only coincides with itself; but the self-conscious understanding is not merely implicit, but essentially explicit, since it is within itself all things. That is an idealistic way of expressing it; and yet they say that Aristotle is an empiricist.