Certainty

Appendix 10.(1242).

The distinction between the various essences of things enables us to reconcile opinions of St. Thomas Aquinas which otherwise might seem opposed to one another. On more than one occasion he says that the substance and quiddity of a thing is the proper object of the intellect, provided however that 'the intellect penetrates the intimate nature of the species which is in the individuals themselves' (De Verit., q. 10, art 5). This takes place especially in the perception of ourselves. When we perceive ourselves, we perceive the term of the very act by which we exist, and hence our essence, to which that act extends.

Elsewhere he says that 'in a mind' such as the human mind 'which receives knowledge from things, the forms', the ideas, 'exist through a certain action of things in the soul'.

Again: That which is known through intellectual vision are things themselves, not the images of things. This takes place in the corporeal or sense-vision, not in the spiritual or imaginative vision. The objects of the imagination and sense are accidents from which are constituted certain figures or images of the things; but the object of the intellect is the very essence of the thing, although the intellect knows the essence of the thing through some likeness of the thing. This likeness is the means by which the intellect knows; it is not as though it were the object towards which it has first turned its gaze' (De Verit., 10, 4).

In this passage St. Thomas is speaking of a certain likeness by which the intellect knows essences, and of certain images of things, images which the intellect does not perceive because it reaches out to see things themselves. As far as I can see, the distinction between likeness and the images is that feeling as such has sensation (properly speaking) and corporeal sense-perception. This corporeal sense-perception is the term of the action of external things on us, and renders sensation extra-subjective. But this term of the action (which we need not describe here) corresponds to St. Thomas' feelable image, the phenomenon of sense.

The soul, however, is conscious of experiencing the term of action from external bodies and (in so far as the soul is intellective) sees in the term a being operating on it. This being is thought by means of the idea of being in general which is applied and added to the term of action experienced in feeling. This idea is St. Thomas' likeness by which the intellect knows things. But things are known by the intellect because being is its object. Universal being is determined by the term of action in feeling.

The quality of our knowledge of things, therefore, and their essence as known to us, corresponds to the nature of the action carried out in us. In bodies, as we have shown, the action upon us is substantial. When we speak of corporeal essence, we mean to name the kind of power which modifies us in the way we have shown (cf. 0 T, 692 ss.).

Even in bodies, therefore, we do not perceive the first act by which they are beings, but only their action, the essence known by us which we then express with the word 'body'.

Bodies, however, have different powers over us which specify them from one another, or their various states. This explains why the distinction of the ideas we have of these bodies is determined solely by their accidental actions on us, and why such ideas enable us to know only generic essences, which properly speaking are not complete essences; the powers operating in us take the place of essences. St. Thomas is speaking of these essences in passages where he maintains that the essences of things are unknown to us.

For example, in De Verit., q. 10, art. 1, he says: 'The essences of things are unknown to us, but their power is manifested to us through their acts, and we FREQUENTILY', not always, therefore, use the words indicating their powers or potencies to mean their essences.' Shortly afterwards he goes on: 'The substantial differences of things are unknown to us. As a result, those who define these things sometimes' INTERDUM 'use accidental instead of substantial differences in so far as the accidental differences indicate or notify the essence, just as effects proper to a thing notify the cause. Consequently, that which is feelable, taken as the constitutive difference of the animal, is not drawn from feeling understood as potency, but as signifying the very essence of the soul from which the potency flows.'

Our knowledge of God remains negative because we know only the effects of God, and effects which, as finite, are inadequate relative to their cause. St. Thomas says: 'We can love God directly without need to love anything prior to him, even though we are sometimes swept up from visible to invisible things.

Nevertheless we cannot in our state as sojourners know God directly without needing knowledge of something prior to him. Desire follows understanding; the action of desire begins where understanding, which proceeds from effects to causes, ends by coming finally to some kind of knowledge of God by knowing of him what he is not. Then desire reaches out to that which the intellect offers it, without its needing to take all the steps the understanding has taken' (De Verit., q. 10, art. 11).