
For Plato taught that immaterial subsisting forms, which he called "Ideas," are the proper objects of our intellect, and thus first and per se understood by us and, further, that material objects are known by the soul inasmuch as phantasy and sense are mixed up with the mind. I answer that, In the opinion of Plato, immaterial substances are not only understood by us, but are the objects we understand first of all. Therefore immaterial substances cannot be known by human investigation. On the contrary, It is written ( Wisdom 9:16): "The things that are in heaven, who shall search out?" But these substances are said to be in heaven, according to Matthew 18:10, "Their angels in heaven," etc. Therefore our intellect can understand all intelligible substances, even the superior and immaterial. But our sight can see all things corporeal, whether superior and incorruptible or lower and corruptible. Further, as sense is to the sensible, so is intellect to the intelligible. Therefore immaterial substances can be understood by us. ii) that " nature would be frustrated in its end" were we unable to understand abstract substances, "because it would have made what in itself is naturally intelligible not to be understood at all." But in nature nothing is idle or purposeless. Therefore they are much more known to us than are material things. As material things, however, are intelligible only so far as we make them actually so by abstracting them from material conditions, it is clear that those substances are more intelligible in themselves whose nature is immaterial. Therefore things which are in themselves in the highest degree of intelligibility, are likewise to us most intelligible. But the intellect is not subject to such a corrupting influence from its object, as is stated De Anima iii, 4. Further, the fact that objects which are in themselves most sensible are not most felt by us, comes from sense being corrupted by their very excellence. Since then our mind understands material things, much more is it able to understand immaterial things.

But the human mind is more akin to immaterial than to material things since its own nature is immaterial, as is clear from what we have said above ( I:76:1). Therefore the human mind understands immaterial substances. ix, 3) says: "As the mind itself acquires the knowledge of corporeal things by means of the corporeal senses, so it gains from itself the knowledge of incorporeal things." But these are the immaterial substances. It would seem that the human soul in the present state of life can understand immaterial substances in themselves.

Whether the human soul in the present state of life can understand immaterial substances in themselves?

