Chapter 4: Intelligible Being And First Principles

St. Thomas, following Aristotle, teaches that the intelligible being, the intelligible reality, existing in sense objects is the first object of the first act of our intellect, i. e.: that apprehension which precedes the act of judging. Listen to his words: "The intellect's first act is to know being, reality, because an object is knowable only in the degree in which it is actual. Hence being, entity, reality, is the first and proper object of understanding, just as sound is the first object of hearing." [123] Now being, reality, is that which either exists (actual being) or can exist (possible being): "being is that whose act is to be." [124] Further, the being, the reality, which our intellect first understands, is not the being of God, nor the being of the understanding subject, but the being, the reality, which exists in the sense world, "that which is grasped immediately by the intellect in the presence of a sense object." [125] Our intellect, indeed, is the lowest of all intelligences, to which corresponds, as proper and proportioned object, that intelligible reality existing in the world of sense. [126] Thus the child, knowing by sense, for example, the whiteness and the sweetness of milk, comes to know by intellect the intelligible reality of this same sense object. "By intellect he apprehends as reality that which by taste he apprehends as sweet." [127] .

In the intelligible reality thus known, our intellect seizes at once its opposition to non-being, an opposition expressed by the principle of contradiction: Being is not non-being. "By nature our intellect knows being and the immediate characteristics of being as being, out of which knowledge arises the understanding of first principles, of the principle, say, that affirmation and denial cannot coexist (opposition between being and non-being): and other similar principles." [128] Here lies the point of departure in Thomistic realism.

Thus our intellect knows intelligible reality and its opposition to nothing, before it knows explicitly the distinction between me and non-me. By reflection on its own act of knowledge the intellect comes to know the existence of that knowing act and its thinking subject. Next it comes to know the existence of this and that individual object, seized by the senses. [129] In intellective knowledge, the universal comes first; sense is restricted to the individual and particular.

From this point of departure, Thomistic realism is seen to be a limited realism, since the universal, though it is not formally, as universal, in the individual sense object, has nevertheless its foundation in that object. This doctrine rises thus above two extremes, which it holds to be aberrations. One extreme is that of absolute realism held by Plato, who held that universals (he calls them "separated ideas") exist formally outside the knowing mind. The other extreme is that of Nominalism, which denies that the universal has any foundation in individual sense objects, and reduces it to a subjective representation accompanied by a common name. Each extreme leads to error. Platonist realism claims to have at least a confused intuition of the divine being (which it calls the Idea of Good). Nominalism opens the door to empiricism and positivism, which reduce first principles to experimental laws concerning sense phenomena. The principle of causality, for example, is reduced to this formula: every phenomenon presupposes an antecedent phenomenon. First principles then, conceived nominalistically, since they are no longer laws of being, of reality, but only of phenomena, do not allow the mind to rise to the knowledge of God, the first cause, beyond the phenomenal order.

This limited moderate realism of Aristotle and Aquinas is in harmony with that natural, spontaneous knowledge which we call common sense. This harmony appears most clearly in the doctrine's insistence on the objective validity and scope of first principles, the object of our first intellectual apprehension. These principles are laws, not of the spirit only, not mere logical laws, not laws merely experimental, restricted to phenomena, but necessary and unlimited laws of being, objective laws of all reality, of all that is or can be.

Yet even in these primary laws we find a hierarchy. One of them, rising immediately from the idea of being, is the simply first principle, the principle of contradiction; it is the declaration of opposition between being and nothing. It may be formulated in two ways, one negative, the other positive. The first may be given either thus: "Being is not nothing," or thus: "One and the same thing, remaining such, cannot simultaneously both be and not be." Positively considered, it becomes the principle of identity, which may be formulated thus: "If a thing is, it is: if it is not, it is not." This is equivalent to saying: "Being is not non-being." Thus we say, to illustrate: "The good is good, the bad is bad," meaning that one is not the other. [130] According to this principle, that which is absurd, say a squared circle, is not merely unimaginable, not merely inconceivable, but absolutely irrealizable. Between the pure logic of what is conceivable and the concrete material world lie the universal laws of reality. And here already we find affirmed the validity of our intelligence in knowing the laws of extramental reality. [131] .

To this principle of contradiction or of identity is subordinated the principle of sufficient reason, which in its generality may be formulated thus: "Everything that is has its raison d'etre, in itself, if of itself it exists, in something else, if of itself it does not exist." But this generality must be understood in senses analogically different.

This principle, we see, is to be understood analogically, according to the order in which it is found, whether that order is intrinsic (the nature of a circle related to its characteristics): or extrinsic (cause, efficient or final, to its effects). When I ask the reason why, says St. Thomas, [132] I must answer by one of the four causes. Why has the circle these properties? By its intrinsic nature. Why is this iron dilated? Because it has been heated (efficient cause). Why did you come? For such or such a purpose. Why is man mortal? Because he is a material composite, hence corruptible.

Thus the raison d'etre, answering the question "why" (propter quid): is manifold in meaning, but these different meanings are proportionally the same, that is, analogically. We stand here at a central point. We see that the efficient cause presupposes the very universal idea of cause, found also in final cause, and in formal cause, as well as in the agent. [133] Thus the principle of sufficient reason had been formulated long before Leibnitz.

We come now to the principle of substance. It is thus formulated: "That which exists as the subject of existence [134] is substance, and is distinct from its accidents or modes." [135] Thus in everyday speech we call gold or silver a substance. This principle is derived from the principle of identity, because that which exists as subject of existence is one and the same beneath all its multiple phenomena, permanent or successive. The idea of substance is thus seen to be a mere determination of the idea of being. Inversely, being is now conceived explicitly as substantial. Hence the conclusion: The principle of substance is simply a determination of the principle of identity: accidents then find their raison d'etre in the substance. [136] .

The principle of efficient causality also finds its formula as a function of being. Wrong is the formula: "Every phenomenon presupposes an antecedent phenomenon." The right formula runs thus: "Every contingent being, even if it exists without beginning, [137] needs an efficient cause and, in last analysis, an uncreated cause." Briefly, every being by participation (in which we distinguish the participating subject from the participated existence) depends on the Being by essence. [138] .

The principle of finality is expressed by Aristotle and Aquinas in these terms: "Every agent acts for a purpose." The agent tends to its own good. But that tendency differs on different levels of being. It may be, first, a tendency merely natural and unconscious, for example, the tendency of the stone toward the center of the earth, or the tendency of all bodies toward the center of the universe. Secondly, this tendency may be accompanied by sense knowledge, for example, in the animal seeking its nourishment. Thirdly, this tendency is guided by intelligence, which alone knows purpose as purpose, [139] that is, knows purpose as the raison d'etre of the means to reach that purpose. [140] .

On this principle of finality depends the first principle of practical reason and of morality. It runs thus: "Do good, avoid evil." It is founded on the idea of good, as the principle of contradiction on the idea of being. In other words: The rational being must will rational good, that good, namely, to which its powers are proportioned by the author of its nature. [141] .

All these principles are the principles of our natural intelligence. They are first manifested in that spontaneous form of intelligence which we call common sense, that is, the natural aptitude of intelligence, before all philosophic culture, to judge things sanely. Common sense, natural reason, seizes these self-evident principles from its notion of intelligible reality. But this natural common sense could not yet give these principles an exact and universal formulation. [142] .

As Gilson [143] well remarks, Thomistic realism is founded, not on a mere postulate, but on intellectual grasp of intelligible reality in sense objects. Its fundamental proposition runs thus: [144] The first idea which the intellect conceives, its most evident idea into which it resolves all other ideas, is the idea of being. Grasping this first idea, the intellect cannot but grasp also the immediate consequences of that idea, namely, first principles as laws of reality. If human intelligence doubts the evidence of, say, the principle of contradiction, then—as Thomists have repeated since the seventeenth century—the principle of Descartes [145] simply vanishes. If the principle of contradiction is not certain, then I might be simultaneously existent and non-existent, then my personal thought is not to be distinguished from impersonal thought, nor personal thought from the subconscious, or even from the unconscious. The universal proposition, Nothing can simultaneously both be and not be, is a necessary presupposition of the particular proposition, I am, and I cannot simultaneously be and not be. Universal knowledge precedes particular knowledge. [146] .

This metaphysical synthesis, as seen thus far, does not seem to pass notably beyond ordinary natural intelligence. But, in truth, the synthesis, by justifying natural intelligence, does pass beyond it. And the synthesis will rise higher still by giving precision to the doctrine on act and potency. How that precision has been reached is our next topic.