73. Distinction between the Individual Nature and its Subsistence. What constitutes Personality?—Knowing now what we mean by the terms “subsistence,” “suppositum,” “person,” and “personality,” we have next to inquire in what precisely does subsistence consist. What is it that constitutes a complete individual nature a “subsisting being,” or if the nature be rational, a “person”? Subsistence connotes, over and above the mode of “existing in itself” which characterizes all substance, the notion that the substance or nature is individual, that it is complete, that it is in every way incommunicable, that it is sui juris or autonomous in its existence and activities. These notions are all positive; they imply positive perfections: even incommunicability is really a positive perfection though the term is negative. But is any one of the positive perfections, thus contained in the notion of subsistence, a positive something over and above, and really distinct from, the perfection already implied in the concept of a complete individual nature as such?
Some of those philosophers who regard the distinction between essence and existence in creatures as a real distinction, identify the subsistence of the complete individual nature with its actual existence, thus placing a real distinction between nature and subsistence or personality.[292] Apart from these, however, it is not likely that any philosophers, guided by the light of reason alone, would ever have held, or even suspected, that the subsistence of an actually existing individual nature is a positive perfection really distinct from, and superadded to, the latter. For we never, in our natural experience, encounter an existing individual substance, or nature, or agent, that is not distinct, autonomous, independent, sui juris, and incommunicable in its mode of being and acting.
Rigorously, however, this would only prove that subsistence is a perfection naturally inseparable from the complete individual nature; conceivably [pg 267] it might still be really distinct from the latter. But whether or not such real distinction could be suspected by the unaided light of reason working on natural experience, at all events what we know from Divine Revelation concerning the hypostatic union of the human nature of our Lord Jesus Christ with the Person of the Divine Word, enables us to realize that there can be, in the actual order of things, a complete individual nature which is not a “subsisting being” or “person”; for the human nature of our Lord is de facto such a nature,—and ab actu ad posse valet consecutio. This information, however, is not decisive in determining the character of the distinction between the individual substance or nature and its subsistence.
It may be that the complete individual nature is eo ipso and identically a “subsisting being” or “person,” that it is always independent, autonomous, sui juris, by the very fact that it is a complete individual nature, unless it is de facto assumed into the personality of a higher nature, so that in this intercommunication with the latter, in the unity of the latter's personality, it is not independent, autonomous, sui juris, but dependent, subordinate, and alterius juris. In this condition, it loses nothing positive by the fact that it is not now a person and has not its own subsistence; nor does it gain any natural perfection, for it was ex hypothesi complete and perfect as a nature; but it gains something supernatural inasmuch as it now subsists in a manner wholly undue to it.[293] According to this view, therefore, subsistence would not be a perfection really distinct from the complete individual nature; it would be a mentally distinct aspect of the latter, a positive aspect, however, consisting in this nature's completeness, its self-sufficing, autonomous character, and consequent incommunicability.[294]
The principal difficulty against this view is a theological difficulty. As formulated by Urraburu,[295] it appears to involve an ambiguity in the expression “substantial union”. It is briefly this: If the subsistence proper to a complete individual nature adds no positive perfection to the latter, so that the latter necessarily subsists and is a person unless it is actually assumed into a higher personality, and by the very fact that it is not actually so assumed, then the human nature of Christ “is as complete in every way and in every line of substantial perfection, by virtue of its own proper entity, when actually united with the Divine Person, as it would be were it not so united, or as [pg 268] the person of Peter, or Paul, or any other human person is”. But this implies that there are in Christ “two substances complete in every respect”. Now between two such substances “there cannot be a substantial union,” a union which would constitute “one being,” “unum per se ens”. Hence the view in question would appear to be inadmissible.
But it is not proved that the union of “two substances complete in every respect” cannot result in the constitution of a being that is really and genuinely one—“unum per se ens”—in the case in which the union is a personal union. The hypostatic union of the human nature of Christ with the Divine Person is primarily a personal union whereby the former nature subsists by and in the Divine Personality. It has the effect of constituting the united terms “one subsisting being,” and therefore has supereminently, if not formally, the effect of a “substantial union”. Nay, it is a “substantial” union in the sense that it is a union of two substances, not of a substance and accidents; and also in the sense that it is not a mere accidental aggregation or artificial juxtaposition of substances, resulting merely in the constitution of collective or artificial unity, a unum per accidens. But is it a “substantial” union in the sense that it is such a union of substances as results in one “nature”? Most certainly not; for this was the heresy of the Monophysites: that in Christ there is only one nature resulting from the union of the human nature with the Divine. If then, with Urraburu, we mean by “nature” simply “substance regarded as a principle of action” ([71]), and if, furthermore, the hypostatic union does not result in one “nature,” neither does it result in one “substance,” nor can it be a “substantial” or “natural” union in this sense.[296] He does not say, of course, that the hypostatic union is a “substantial union” which results in “one nature,” or even explicitly that it results in “one substance,” but he says that the two substances are “substantially conjoined,” “substantialiter conjunguntur”; and he continues, “a substantial union is such a conjunction of two substantial realities that there results from it one substantial something, which is truly and properly one”—“unio enim substantialis, est talis duarum rerum substantialium conjunctio, per quam resultat unum aliquid substantiale quod vere et proprie sit unum,”[297]—and he concludes that “there is something substantial wanting in the human nature of Christ, viz. personality, which, of course, is most abundantly supplied in the hypostatic union by the Divine Person”—“reliquum est, ut naturae humanae in Christo aliquid desit substantiale, nempe personalitas, quod per unionem hypostaticam cumulatissime suppleatur a Verbo.”[298] Now, this “aliquid substantiale” cannot be “aliquid naturale” in the sense that it is something constitutive of the human [pg 269] substance or nature; for the human substance or nature of Christ is certainly complete and perfect as a substance or nature. It must be some complement or mode, that is naturally due to it, but supernaturally supplied by the Person of the Divine Word.[299] This brings us to the view that subsistence is a something positive, distinct in some real way, and not merely in our concepts, from the complete individual substance.
According to the more common view of catholic philosophers (and theologians) subsistence is some positive perfection really distinct from the complete individual nature. But the supporters of this general view explain it in different ways. We have already referred to the view of certain Thomists who, identifying subsistence with the actual existence of the complete substance or nature, place a real distinction between the existence and the substance or nature. Other Thomists, while defending the latter distinction, point out that actual existence confers no real perfection, but only actualizes the real; they hold, therefore, that subsistence is not existence, but is rather a perfection of the real, essential, or substantial order, as distinct from the existential order—a perfection presupposed by actual existence, and whose proper function is to unify all the substantial constituents and accidental determinations of the individual substance or nature, thus making it a really unitary being—“unum ens per se”—proximately capable of being actualized by the simple existential act: which latter is the ultimate actuality of the real being: esse est ultimus actus.[300]
The concrete individual nature, containing as it does a plurality of really distinct principles, substantial and accidental, needs some unifying principle to make these one incommunicable reality, proximately capable of receiving a corresponding unitary existential act: without such a principle, they say, each of the substantial and accidental principles in the concrete individual nature would have its own existence: so that the result would be not really one being, but a being really manifold and only accidentally one—“unum per accidens”. This principle is subsistence.
The human nature of our Divine Lord has not its own connatural subsistence; this is supplied by the subsistence of the Divine Person. Moreover, since the human nature in question has not its own subsistence, neither has it its own existence; existence is the actuality of the subsisting [pg 270] being; therefore there is in Christ but one existence, that of the Divine Person, whereby also the human nature of Christ exists.[301]
Of those who deny that the distinction between the existence and the essence of any created nature is a real distinction, some hold in the present matter the Scotist view that subsistence is not a positive perfection really distinct from the complete individual nature. Others, however, hold what we have ventured to regard as the more common view: that personality is something positive and really distinct from nature. But they explain what they conceive subsistence to be without any reference to existence, and without distinguishing between the essential and the existential order of reality.