The Medieval world knew Aristotle from the translations of Boethius and the Muslim commentators, all of which interpreted the Stagarite through the lens of his Neoplatonic commentators. Aquinas realized that the Liber de Causis was written by Proclus, not Aristotle as tradition claimed. Yet, he continued commenting on that book and was influenced by it, and he was influenced by the Neoplatonism of the Pseudo-Dionysius. As Kristeller notes, during the time of the Renaissance philosophers began to examine the context and grammar of Aristotle’s writings, seeking to study him on his own terms rather than secondarily through the interpretation of the Neoplatonists.
However, this “rebirth” of the tools of investigation, particularly with regard to Aristotelian philosophy, did not lead theologians to dispose of all things Platonic in the search of a “perennial” philosophy. There were humanists, Thomists, Scotists, Occamists, Augustinians and many others during this era, still endeavoring to find the Archimedean point between the Queen of the sciences and her handmaiden. But, all of these groups were fundamentally Augustinian, and thus could not forsake a certain Neoplatonism. Peter Martyr exemplifies this humanist renewal in Aristotelean studies coupled with a reiterated Platonism. I demonstrated this a while back in a post on the Divine Ideas. Martyr carried on this doctrine, saying that these ideas are God’s contemplation of himself as he may be expressed in infinite ways and are thus the exemplar causes of all things. He also was not afraid to affirm that Plato had an accurate conception of God:
Plato had a very clear notion of God. First, that God is one and is ineffable: he is one, so we do not have to go on to infinity [immensum] in search of causes, for it is true that he is the first cause; he is ineffable, since in human speech there are no words that can express the divine properties. If a man acquired equine nature, he would not be able to transmit to other horses what ha had devised in his human mind. Similarly, philosophers and great thinkers, even if they have a sublime knowledge of God, have no words to express it. Besides, Plato knew that God comprises everything and at the same time exceeds everything, so that there is no kind of miniscule good that God would not possess, nor is there such enormous good that he would not surpass and to which he would not be superior. God pervades all things and never goes outside himself. Even if he is infinite, wherever he is, he is in himself. He produces everything and is prompted by no other reason than his own goodness. For there can exist nothing superior to his goodness that god would seek in creation of the universe; Good is good and produced everything that he made out of his goodness. His goodness is not acquired through application or effort as in the case o human goodness, but is inherent to him and is naturally implanted in his mind. Therefore he did not acquire it by his will or choice. Similarly, the sun enlightens everything with its brightness that it di not acquire, but possesses as something inborn and innate. And all things not only owe their creation to God but also tend toward him as their ultimate goal. Therefore it is no wonder that everything is related to him, since the perfection of all things depends on him. Plato understood and explained in his writings very clearly those aspects of God’s nature that I have just reviewed as well as many other concepts. The same concepts are contained both in holy scripture and in ancient ecclesiastical writers. (Commentary on Aristotle’s Nicomachean Ethics, pp. 136, 137.)
This attribution of divine knowledge to the pagan philosopher may be shocking to some Christians but it was a common opinion. Luther and Calvin believed that the pagan had a natural knowledge of the first table of the Decalogue but lacked a knowledge of the second. As I noted here, Calvin believed that the unbeliever needs to know how to worship God rather than just gain an understanding of God, an understanding that Calvin says they already have.
Peter Martyr’s perspective on Plato and Aristotle is still very much Medieval. He quotes Boethius and Averroes (whom he calls “the greatest of the Peripatetics”) as well as Augustine as authorities on the doctrine of the Ideas. Yet, he also translates Aristotle from the Greek text and examines phrases and words, demonstrating the philological methods of a new day and time. Plato’s doctrines are useful inasmuch as they reflect the true foundation of all things in the divine mind. Yet, Martyr, once again demonstrating his humanist mentality, does not care for Plato’s ideas beyond the necessity of exemplar causes. He notes, “For even if such Ideas – of one kind or another – really existed, we would not find them useful in our actions.” (ibid., p. 170.) In other words, even if men could have some sort of participation in the divine ideas through contemplation, this sort of knowledge would leave us no closer to the good than the mentally ill. We may only approach the good through acts of virtue and wisdom, and we must abandon Plato for Aristotle when he directs us elsewhere. Thus, Plato’s philosophy is necessary for certain principles of our doctrine of God, but we must lean on Aristotle for our method and pursuit of the common good.