(b) Efficient causality, actio et passio, can undoubtedly be the ground of real predicamental relations. If the action is transitive[414] the patiens or recipient of the real change acquires by this latter the basis of a relation of real dependence on the cause or agens. Again, if the action provokes reaction, so that there is real interaction, each agens being also patiens, there arises a mutual predicamental relation of interdependence between the two agencies. Furthermore, if the agent itself is in any way really perfected by [pg 348] the action there arises a real predicamental relation which is mutual: not merely a real relation of effect to agent but also of agent to effect. This is true in all cases of what scholastics call “univocal” as distinct from “equivocal” causation. Of the former, in which the agent produces an effect like in nature to itself, the propagation of their species by living things is the great example. Here not only is the relation of offspring to parents a real relation, but that of parents to offspring is also a real relation. And this real relation is permanent because it is grounded not merely in the transient generative processes but in some real and abiding result of these processes—either some physical disposition in the parents themselves,[415] or some specific perfection attributed by extrinsic denomination to the individual parents: the parents are in a sense continued in their offspring: “generation really perpetuates the species, the specific nature, and in this sense may be said to perfect the individual parents”.[416] In cases of “equivocal” causation—i.e. where the effect is different in nature from the cause, as when a man builds a house—the agent does not so clearly benefit by the action, so that in such cases, while the relation of the effect to the cause is real, some authors would regard that of the cause to the effect as logical.[417] When, however, we remember that the efficient activity of all created causes is necessarily dependent on the Divine Concursus, and necessarily involves change in the created cause itself, we can regard this change as in all cases the ground of a real relation of the created cause to its effect. But the creating and conserving activity of the Divine Being cannot ground a real relation of the latter to creatures because the Divine Being is Pure and Unchangeable Actuality, acquiring no new perfection, and undergoing no real change, by such activity.[418]
(c) By commensuration as a basis of real relations Aristotle does not mean quantitative measurement, but the determination of the perfection of one reality by its being essentially conformed to, and regulated by, another: as the perfection of knowledge or [pg 349] science, for instance, is determined by the perfection of its object. This sort of commensuration, or essential ordination of one reality to another, is obviously the basis of transcendental relations. Some authors would consider that besides the transcendental relation of science to its object, a relation which is independent of the actual existence of the latter, there also exists an accidental relation in science to its object as long as this latter is in actual existence. But rather it should be said that just as the transcendental truth-relation of any real object to intellect is fundamental (potential) or formal (actual) according as this intellect merely can know this object or actually does know it, so also the transcendental relation of knowledge to its object is fundamental or formal according as this object is merely possible or actually existing.
We gather from the foregoing analysis that the three main classes of predicamental relations are those based on quantity, quality, and causality, respectively.
93. In What does the Reality of Predicamental Relations Consist?—We have seen that not all relations are purely logical. There are real relations; and of these some are not merely aspects of the other categories of real being, not merely transcendental attributes virtually distinct from, but really identical with, these other absolute modes of real being which we designate as “substance,” “quantity,” “quality,” “cause,” “effect,” etc. There are real relations which form a distinct accidental mode of real being and so constitute a category apart. The fact, however, that these predicamental relations have been placed by Aristotle and his followers in a category apart does not of itself prove that the predicamental relation is a special reality sui generis, really and adequately distinct from the realities which constitute the other categories ([60]). If the predicamental relation be not a purely logical entity, if it be an ens rationis cum fundamento in re, or, in other words, if the object of our concept of “predicamental relation,” has a foundation in reality (e.g. like the concepts of “space” and “time”), then it may reasonably be placed in a category apart, even although it may not be itself formally a reality. We have therefore to see whether or not the predicamental relation is, or embodies, any mode of real being adequately distinct from these modes which constitute the other categories.
The predicamental relation is real in the sense that it implies, in addition to two really distinct extremes, a real foundation in [pg 350] one or both of these extremes, a real accident such as quantity, quality, or causality. That is to say, considered in its foundation or cause, considered fundamentally or secundum suum esse in subjecto, the predicamental relation is real, inasmuch as its foundation is a reality independently of the consideration of the mind. No doubt, if the predicamental relation, adequately considered, implies no other reality than that of its foundation and terms, then the predicamental relation does not contain any special reality sui generis, distinct from substances, quality, quantity, and other such absolute modes of real being. This, however, does not prevent its ranking as a distinct category provided it adds a virtually distinct and altogether peculiar aspect to those absolute realities. Now, considered adequately, the predicamental relation adds to the reality it has in its foundation the actual reference of subject to term. In fact, it is in this reference of subject to term, this “esse ad,” that the relation formally consists. The question therefore may be stated thus: Is this formal relation of subject to term, this “esse ad” a real entity sui generis, really distinct from the absolute entities of subject, term and foundation, and in contradistinction to these and all absolute entities a “relative entity,” actually existing in the real universe independently of our thought? Or is it, on the contrary, itself formally a mere product of our thought, a product of the mental act of comparison, an ens rationis an aspect superadded by our minds to the extremes compared, and to the foundation in virtue of which we compare them?
A good many scholastics, and some of them men of great name,[419] [pg 351] have espoused the former alternative, considering that the reality of the predicamental relation cannot be vindicated—against idealists, who would reduce all relations to mere logical entities—otherwise than by according to the relation considered formally, i.e. secundum suum “esse ad,” an entity in the actual order of things independent of our thought: adding as an argument that if relation formally as such is anything at all, if all relation be not a mere mental fabrication, it is essentially a “relative” entity, and that manifestly a “relative” entity cannot be really identical with any “absolute” entity. And they claim for this view the authority of St Thomas.[420]
The great majority of scholastics, however, espouse the second alternative: that the relation, considered formally, “secundum esse ad,” is a product of our mental comparison of subject with term. It is not itself a real entity or a real mode, superadded to the reality of extremes and foundation.
In the first place there is no need to suppose the reality of such a relative entity. Entia non sunt multiplicanda præter necessitatem. It is an abuse of realism to suppose that the formal element of a relation, its “esse ad,” is a distinct and separate reality. The reality of the praedicamental relation is safeguarded without any such postulate. Since the predicamental relation, considered adequately, i.e. not merely formally but fundamentally, not merely secundum esse ad but secundum esse in, involves as its foundation an absolute accident which is real independently of our thought, the predicamental relation is not a mere ens rationis. It has a foundation in reality. It is an ens rationis cum fundamento in re. This is a sufficient counter-assertion to Idealism, and a sufficient reason for treating relation as a distinct category of real being.
That there is no need for such a relative entity will be manifest if we consider the simple case of two bars of iron each a yard long. The length of each is an absolute accident of each. The length of either, considered absolutely and in itself, is not formally the equality of this with the other. Nor are both lengths considered separately the formal relation of equality. But both considered together are the adequate foundation of this formal relation; both considered together are this relation potentially, fundamentally, so that all that is needed for the actual, formal relation of equality is the mental apprehension of the two lengths together. The mental process of comparison is the only thing required to make the potential relation actual; and the product of this mental process is the formality or “esse ad” of the relation, the actual reference of the extremes to each other. Besides the absolute accidents which constitute the foundation of the relation something more is required for the constitution of the adequate predicamental relation. This “something more,” however, is a mind capable of comparing the extremes, and not any real entity distinct from extremes and foundation. Antecedently to the act of comparison the formally relative element of the relation, its “esse ad,” was not anything actual; it was the mere comparability of the extremes in virtue of the foundation. If the “esse ad” were a separate real entity, a relative entity, really [pg 353] distinct from extremes and foundation, what sort of entity could it be? Being an accident, it should inhere in, or be a mode of its subject. But if it did it would lose its formally relative character by becoming an inherent mode of an absolute reality. While to conceive it as an entity astride on both extremes, and bridging or connecting these together, would be to substitute the crude imagery of the imagination for intellectual thought.
In the second place, if a subject can acquire a relation, or lose a relation, without undergoing any real change, then the relation considered formally as such, or secundum “esse ad,” cannot be a reality. But a subject can acquire or lose a relation without undergoing any real change. Therefore the relation considered formally, as distinct from its foundation and extremes, is not a reality.