One point on which I sharply differ from Pippin is his claim that Aristotelian intellect is purely passive. I think I have sufficiently documented that this is not historically accurate. But the context of Pippin’s claim is Kant’s great elaboration of the active side of judging and thinking. And undoubtedly, Kant was arguing against a received view. So whose view was it?
I think the answer has to be Leibniz, his popularizer Christian Wolff, and the Wolffians like Mendelsohn and Baumgarten who dominated philosophy in German universities in Kant’s time. An examination of Kant’s work shows that most of the received views Kant argues against are Wolffian views.
Basic to Leibniz’s and the Wolffians’ point of view is a very categorical preformationism. One of Leibniz’s best known theses asserts a pre-established harmony that not only aims to explain the relationship of mind and body, but encompasses all things whatsoever. According to Leibniz, God creates nothing less than an entire, coherent world, every detail of which is providentially anticipated in advance. Once there is a world, God never “intervenes” in it, because all the work of providence was done in creation. (Providence in the Greek (pronoia) is literally forethought.) God’s creative act consists in the selection of the best of all possible worlds. I personally regard the pre-established harmony as a kind of Platonic myth or “as if” — a speculative hypothesis that makes a kind of poetic sense, but is nonetheless very extravagant.
Consistent with his assertion of pre-established harmony, Leibniz denies that there is real causal interaction between things in the world. Instead, each being carries within it a microcosm of the whole, and is causally affected only by God.
One of Kant’s earliest publications was a defense of real causal interaction against Leibniz. Whether or not Kant thought about it at the time, he was effectively defending an Aristotelian view of the reality of secondary causes. Against this wider background, Kant’s later insistence on the active character of thought can be seen as taking the perspective that we too rank among the real secondary causes.
If the harmony of all things were pre-established, there would be no active work for intellect to do. It would just need to assimilate itself to the pre-established harmony. Intellect would thus be a passive recognition of pre-existing structures. Thus the Leibnizian-Wolffian world view intrinsically promotes the passivity of intellect that Kant opposes.