-Thomist theories of knowledge are grounded on De veritate 2.2. Though the article deals formally with God’s knowledge of himself Thomas answers the problem from an account of knowledge as such.
-The account starts from the perfectio rei or actuality as opposed to potency.
-Our first notion of actuality is what constitutes a thing in act and so gives it a species. This is basic hylomorphic theory.
-The theory of knowledge begins with Thomas’s claim that (hylomorphic) perfection considered in itself is imperfect, since it is only a part of the universe. Thomas calls “the remedy” of this that the actuality itself perfects both what it gives specific existence to and another. This remedy is not something bolted on top of actuality but is just another dimension of actuality itself.
-Note that by Thomas’s premises the actuality A as known must perfect some other B so far as A is part of the universe, i.e. A must come to B along with the whole plurality of the universe. Before it is anything else, knowledge is the known object existing as part-of-the-universe for another. The order of causality is not first a knower then the known, but first the known, which is nothing other than the actuality of a thing existing in a whole, and that whole exists for another. Just as there is not first the radio then the broadcast, but the broadcast goes forth whether there are radios to receive it or not, so too actuality broadcasts itself, though not according to the existence it has as separate from other things, but according to the existence it has as a part of the universe, and therefore along with the universe.
-Let’s hammer that last point home: Following Aristotle in 1 De anima 1 and 2, Thomas’s account of knowledge starts from the object. We moderns want it to start from the knower, but for Thomas this is the futile attempt to make potency the absolute principle of act. “The object” in a cognitive sense is simply actuality’s self-broadcast going forth whether there is a knower there to receive it or not. A knower is simply one that has found a way to tap into or harness or be perfected by “the object” that actuality has been broadcasting from the beginning, and that it would continue to broadcast even to a cosmos that, whether through its underdevelopment or a catastrophic calamity, had nothing yet sentient or intellective within it. This is also the first meaning of “intentional being” or esse intentionale. It is not first of all being in the mind, but being as broadcast from the world, together with the whole universe, for the reception by another (in fact, a radio wave carrying a signal or an arrow flyign to a target is literally intentional being.) This allows for a certain sense in which the knower is prior to the known, i.e. the way in which a target is prior to the flight of the arrow, but we know now that the broadcast goes forth whether there are knowers to receive it or not. The cosmos first shot the arrow and then made the target.
-Actuality or perfection founds distinct orders of being and knowing, but this distinction arises precisely as actuality is made finite. Actuality as such is infinite and perfect apart from its union to potency (cf. ST 7. a. 1.) It is the same actuality that gives hylomorphic existence and overflows to constitute the order of knowing in its unity with all other actuality: the first unity makes the hylomorphic composite and the makes the universe. Why say it “makes the universe”? Obviously not in some Berkelean sense of projecting it noetically but in the sense that the universe in itself is only one per accidens but it is one per se within knowledge, since knowledge unifies diverse actualities into one world. The sky, a bug and a tree are not one per se, but qua the umwelt of the bird they are.
-So the umwelt of sensation is inherently finite even while including the totality of the universe. Vision is not of being as being but being as broadcast though EM fields. The medium of touch is even more localized. The medium of the sensible, in fact, is always a mix of the world and the body of the animal, and so the objectivity of sense is always conditioned by its subjectivity and the exigencies of what evolved as necessary for survival. The division of primary and secondary sensibles was an attempt to neatly divide the objective and subjective polarities of sensation, but they are nonetheless different ends of an objective-subjective continuum. So sure, the shape of a fruit is probably more objective than its taste, but even shape is conditioned by the disposition of the organ.
-The umwelt of intellect is being, which is to name it according to the very minimal way in which we are intellectual. We know with absolute objectivity that things are but what they are is obscure to us. This obscurity is so profound that we can wonder even whether they are nothing but relations, which would be their only objective character if we lived in a Cartesian theater or a Parmenidean or Einsteinian universe where all motion, becoming, or separation of one thing from another in spacetime is only subjective.
-Cartesian theaters and Einsteinian block-worlds involve logical problems, but the logical problems are subtle and easily missed, allowing for an easy ignorance that makes theaters or block world conceivable (as what is conceivable or not is a function of how many contradictions of which we are aware.) Descartes himself also thought there was a contradiction in a Cartesian theater, as it requires a wicked divinity, but I claim the problem is more basic though more subtle.
-When Thomas defines even sensitive knowledge as non-material the material is only the potency that is informed by act to make finite being. Clearly sensation is non-material in this manner simply because an actuality is not taken as in matter but as a part of the sum of actualities constituting a universe or umwelt. The form of a bug in the order of being is the bug, but in the order of (a bird’s) knowing it is one part within an unbroken umwelt including trees, stars, rivers, the magnetic field of the earth, etc.
-Though Thomas does sometimes speak of the spirituality of sensation the non-materiality of knowledge becomes properly spiritual when the actuality of the object informs another precisely as act. Again, for us this is only in a very indistinct and vague way, so much so that it is to our benefit to have access to sensations that can be used as guides to what distinction, precision, and definiteness look like. Nevertheless, sensation can only be an imitation of what is more perfect in a higher order, and the exitus we exercise in gaining precision about the sensitive world through physical science, poetic creation or the development of prudence must be balanced by the reditus that sees these in their imitation of an order in which all the diverse perfections of sensation are unified in a higher synthesis.
-As said above, actuality as finite gives rise to distinct orders of knowing and being. Where actuality is not finite, therefore, knowing and being are one. We can say they are one in being but it has clearly shifted its sense as it is being no longer used as opposed to knowing but as transcending the opposition between the distinct orders. Note that this transcendent being is on the one hand simply actuality as such, and on the other hand it is not a being since it is not an actuality as opposed to knowledge. We thus have reasons both to call it a being and not a being, and this tension in naming is what gets called analogy, at least the theological analogy that interests Thomas.