Hollands, Edmund H. “Possibility and Reality.” The Philosophical Review 16, no. 6 (1907): 604. https://doi.org/10.2307/2177295
THERE are two typical ways in which the relation of the possible to the real may be conceived. According to the one, possibility is a merely subjective notion; all the possible is in some sense real, and the real includes the possible. According to the other, there is such a thing as absolute possibility; the realm of the possible includes that of the real, and realities are possibilities of a certain kind. The classical statements of these opposed positions are given by Spinoza and by Leibniz; but the issue, in one form or another, is a persistent one. Bosanquet holds that the problematic judgment is really an incomplete form, which would become apodictic so soon as its deficiencies were supplied, he is taking up the first position; and when certain other writers on logical theory teach that there are judgments which, although necessary, have no reference to reality, they are in a measure defending the second. It is possible, therefore, that an examination of the presuppositions of the first view in Spinoza, and of those of the second in Leibniz, may throw some light upon a question which is still under discussion.
Spinoza invariably defines possibility as a notion due to the limitations of our intellect and having no objective validity. The real division is between Necessity and Impossibility, and between these there is no middle ground. It is true that, in the Cogitata metaphysica, he speaks of a division of Being into Being whose essence necessarily involves existence, and Being whose essence involves only possible existence. But this can only be a slip in the use of 'possible,' which is corrected a little later by a definition in the sense already indicated. And with this all the other passages on the subject agree.
Their import is briefly as follows: All things are either necessary or impossible. They may be so either 'respect essential' or 'respect cause.' God is the only being who is necessary in the first way, or, as one might say, by definition. Anything whose nature involves a contradiction, as for example a Chimaera, will be impossible in the first way. On the other hand, all things falling between these two extremes of self-evident necessity and impossibility will be necessary or impossible according as their adequate cause does or does not exist. All actually existent finite things are necessary in this second way; and the necessity as to their essence, depends on the general laws of Nature, and, as to existence, on the particular order of the causal series in question. Possibility, however, is a classification born of our ignorance. When the notion of a finite thing is apparently self-consistent, and we know what its adequate cause would be, but do not know whether that cause exists, we call it contingent, because its concept permits of our attributing existence to it, without necessitating it; or possible, because we are uncertain as to the existence of its cause. The removal of this uncertainty would in every case put the thing provisionally styled possible under the head of the necessary or of the impossible.
This abbreviated statement of the position seems very abstract and formal, and in certain respects it is open to obvious objection. The notion that the mere analysis of a definition, apart from all experience, can show the impossibility of the thing defined, is of course entirely untenable. But criticism of this abstract conceptualism does not necessarily invalidate Spinoza's contention that all the existent is necessary both a priori and posteriori, and that there is no actual 'possibility' with which it might be compared. This view is essential to the whole system and is an inevitable result of its presuppositions.
The way in which it is deduced in the Cogitata metaphysic shows clearly its origin in the logical development of the Cartesian definition of substance. We can clearly conceive of any finite thing as non-existent, says Spinoza; therefore, its essence does not involve existence, and it can exist only because " of a cause, that is, God, the creator of all things." "If, therefore, it is contained in the divine decree that anything should exist, it will necessarily exist; but if not, its existence will be impossible. “The mention of a divine decree sounds like orthodox Cartesians: but we are told a moment later that, since God's nature is immutable, his decrees must be for all eternity ; and that " we cannot say that things are contingent, because God might have decreed otherwise ; for since in eternity there is no when, or before, or after, or any temporal qualification, it follows that God was not before his decrees, so that he could decree differently. “Consequently, “the existence of all created things is necessary from all eternity." The passage is interesting, both as showing how Spinoza was modifying the Cartesian doctrine while retaining its terms, and also because, by its retention of theological phraseology, it states his position in sharp contrast with that of Leibniz.
In the Ethics the logical principles involved come out more clearly, since the doctrine is given in its complete and proper form. God is the sum-total of all being. His existence is necessary, and all finite beings, which are but ' modes ' or parts of his, exist by the same necessity. It is true that their necessity is derivative; the existence of the parts is carried over from one moment to the other only by the nature of the whole; and this is the only form of 'contingency' which Spinoza allows. The order and nature of finite beings is absolutely determined by the nature of the whole; a different world would mean a different God, which is absurd. This is what might be called the exclusive side of the theory, its thoroughgoing determinism. But it has also an inclusive aspect. There is no such thing as bare possibility; infinite reality must realize itself with infinite diversity, and all the possible exists. Non-existence as well as existence requires a cause or reason; and therefore, all the really possible is really necessary. The necessities, of course, different in its immediate form for the finite individual thing and for the Absolute. The difference is parallel to that between duration and eternity. God has his necessity in himself; but it is the very characteristic of the finite to be determined from without. Every finite being, therefore, depends upon another finite, and the chain of finite causes is interminable. This conclusion is strikingly like Leibniz's description of the contingent (or finite, which for him is the same thing) as the indefinitely analyzable.
This hurried outline is, of course, an inadequate account of the grounds of Spinoza's position in this matter. And in any case, it might seem as though it were merely an outgrowth of his abstract conceptualism in epistemology and substantialist pantheism in metaphysics. So, to interpret it, however, would be unjust to the real strength of his position. It also rests upon certain other general presuppositions which do not stand or fall with his particular type of metaphysics. Chief among these is the assumption that there is a principle of order in the universe, a systematic whole of things.
Few philosophers of any period or type would deny this since it is the fundamental postulate of all philosophizing. Once grant this principle of universal order, however, and all the rest follows, from Spinoza's point of view, as a matter of course. We can then admit no gaps either in the series of general or 'eternal ‘truths, or in the chain of mechanical causation in which these general principles take effect. To admit that there are exceptions to their application, or that they do not determine every real thing to its last detail, would be to deny the unity of the universe. But this is just what we do when we pretend that there is such a thing as objective possibility. A thing that was merely possible would be one to which the actual system of things was indifferent, which was neither accepted nor rejected by it. Possible things, therefore, would have no place in the system of actual things, but would form a world of their own, which would require connection with the actual by some external link or bridge, such as the divine understanding according to Leibniz. As a matter of fact, Spinoza’s position implies a thorough acceptance of the existential theory of judgment. Every really definite judgment connects its subject with reality, and that the more precisely the more definite and complete it is. He is only putting this into metaphysical terms, when he tells us that every 'essence' which is not merely fictitious has existence at some time or other; it exists by the same right as the systematic whole in which it is given palace, and, as it were, at one stroke with it." God," as he says," is the efficient cause of all things which can be objects of the divine intellect." "If there is a God, he can have no fictitious ideas." For Spinoza the universe of thought and that of reality have, in their ideal completion, precisely the same boundaries, and the necessity of the one is also that of the other.
When we turn from Spinoza to Leibniz, we find that strict logical consistency has been to some extent given up, in order to meet what seem to be ethical and religious demands. At the same time, the logical principles involved are much more explicitly worked out, and the treatment of the matter is in many respects more concrete.
The theological reason why Leibniz insists that there are real possibilities is, baldly stated, that God does not seem to him to have real freedom unless he is able to choose between really possible alternatives. " If one tried to reject absolutely the purposeless, one would destroy contingency and liberty. For if there were nothing possible except what God has actually created, whatever God created would be necessary." The region of these real possibilities is the divine understanding, to which the essences of possible things are objects. Existence, a predicate which does not affect the essence of a thing, is given to such things as become actual by the divine will. God's " understanding is the source of essences, and His will is the origin of existences. “Essences, therefore, are necessarily what they are; but existing things, qua existing, are contingent. We must distinguish between eternal truths, which would be valid for every possible world, and those particular principles of existing being which are valid only for the actual world.
The objectivity of possibility is then an ethic-religious postulate for Leibniz. But it is also based on his logical theory, between which and his metaphysics there is an exact and too often neglected correspondence. He points out that we may sharply distinguish between necessary, self-evident, or eternal truths, and contingent or empirical truths. The opposite of the former is impossible; of the second, possible. But necessary truths can also be analyzed into primary simple ideas and propositions self-evidently true and irreducible, while the analysis of contingent truths, though possible, is endless, since it never arrives at self-evident, or identical, propositions. Now it is apparent that essences are only the metaphysical counterparts of eternal truths, while existent things, with their interminable chain of causation, correspond to contingent truths. The principle of contradiction is a sufficient test of the first pair, while for the second we must call in that of sufficient reason. The metaphysical distinction is, therefore, justified by the logical.
Leibniz also explicitly derives the principle of sufficient reason from the analytic theory of judgment. "In every affirmative proposition, whether veritable, necessary or contingent, universal or singular, the concept of the predicate is comprised in some sorting that of the subject." He says in a letter to Arnold: "It only in this sense that I say that the concept of an individual substance involves all of its changes and all its relations, even those which are commonly called extrinsic. . .. There must always be some foundation for the connection of the terms of a proposition; and this is found in their concepts. This is a fundamental proposition, which I think all philosophers ought to agree to, and one of the corollaries is that commonly accepted axiom: that nothing happens without a reason which can be given. “It is clear from the correspondence with Arnold that this dictum that all truth is analytic, and that therefore the concept of any particular thing must contain within itself the reasons for every change or state which can be predicated of it, lies at the root of the whole theory of monads. Couturat is scarcely overstating the case when he says that " this logical thesis is the foundation of all Leibniz's metaphysic."
It follows from this principle that all propositions concerning contingents, although they are not necessary, yet are demonstrable priori. Their concepts as complete embrace the decree of God, "taken as possible," which lead to their existence. And although this determinate demonstration is not attainable by the human understanding, we must admit that it is present to the mind of God; and its place is taken, for us, by a causal analysis which, though unending, by its definite nature shows the existence of a necessary ground for the contingent thus analyzed or ‘reduced.' All this, however, while it tells us that there must be a principle of sufficient reason to account for contingents, does not Tellus what that principle is, nor what is its relation to the principle of contradiction. Unfortunately, Leibniz himself is much confused in his statements on both these questions, especially the second. Couturat points out that in contemporary writings varying statements as to the application of the two principles appear. At times that of sufficient reason is said to apply to all truth, necessary as well as contingent; and from its logical derivation one would expect this to be the case. Then again, the principle of contradiction is said to apply only to logical and mathematical truths, while physical, metaphysical, and ethical truths depend only on the principle of sufficient reason. Couturat's solution of the difficulty is that the principle of sufficient reason is the "logical reciprocal" of that of contradiction, since it "affirms . . . that every true proposition is analytic, that is, virtually identical. "It therefore applies to all truths; but we do not need to use it in the abstract sciences which deal with possible essences, while we do need it for the natural sciences, which deal with real existences. “Hence, though all truths depend on the principle of contradiction, the truths of reason are considered as its special field; and in the same way, though all truths depend on the principle of sufficient reason, it is regarded as applying especially to factual truths, which cannot be proved without it." But the sharp division of territory between the two principles comes when we cease to consider the essence of things each for itself and raise the question of their 'compossibility.' It is, then, under the stress of the ethical and religious demand already noticed, that contradiction becomes the law of essences, and sufficient reason that of existences. "The principle of sufficient reason, purely logical in its origin, takes on a metaphysical and theological character."
Another recent commentator, Mr. Bertrand Russell, fails to notice the wider application of the principle, and considers it alone applying only to possible being. But he subjects it to a closer analysis in this sense than Couturat has done and finds that here again it has a double meaning. As a consequence of the principle of contradiction, and applying to all possible worlds whatever, it means that all possible causes are desires, designs, or intentions. But as coordinate with the law of contradiction, and applying only to the actual world, it means that all actual causes are desires for the good, or, in the case of God, for the best.
This last meaning is of course the form in which the principle appears in Leibniz's metaphysics. The principle of sufficient reason is a principium meliorism. Among the possible worlds present to his understanding, God's choice will naturally select the best Those essences 'compossible' with it will become existent; the others will remain merely possible.
But, without raising the difficulty of the origin of incompossibility among essences that in God's understanding are all corn possible, there is lurking under this apparently straightforward statement another conflict between the logic and the ethics of the system. "Essence of itself tends to existence," Leibniz tells us. If his possibilities are to be real, he must assert this. It follows, then, that the more essence, the more right to existence. “Perfection is nothing but a quantity of essence." "Hence it is most evident that out of the infinite possible combinations and series of possible things there exists that one through which the greatest amount of essence or possibility is brought to existence. “Thus, we have physical necessity coming from metaphysical necessity." But if this be true, the 'choice' of God is a mere fiction. The highest sum of essence must gain the day, as against other possible sums, and the principle of sufficient reason as Couturat remarks, takes on a mathematical or mechanical form.
Leibniz is also fond of describing the ' best ' as the largest possible whole of reality determined by the simplest possible principles, and God as the " wisest possible geometer." So that ultimately the principle of sufficient reason, which inclines without necessitating, is just this union of the simplest possible principles with the richest and most varied results.
It is obvious that some of the difficulties we have just rapidly reviewed arise from the fact that Leibniz had never cleared his ethics from the antinomies of common sense. But there are others which are fundamental, and it is significant that they all arise in connection with the doctrine of 'real ‘possibility, and the attempt to employ the principle of sufficient reason as a means to separate what in the possible becomes actual, from what remains merely possible.
Most radical among them are those arising from the separation of essence from existence. As we just saw, Leibniz holds that it makes no difference to the essence of a thing whether it exists or not. Existence is a merely external predicate, tacked on from without, as it were. This is an inevitable position in any attempt to separate actuality from possibility and give the latter an independent status. But note the result. In the first place, Leibniz contradicts his own view as to the nature of a proposition, and can get over the difficulty as to existential predicates only by adding the "sufficient reason" in each case to make up the “total concept" of the thing, a dangerous expedient, wild him at times very close to the Spinozism which he wished to avoid, and annuls real possibility after all. In the recomplete, what is only another aspect of the same dilemma, if existence makes no difference to the essence of a thing, then the existent and the possible belong to different worlds. Leibniz plays fast and loose with this alternative. At one time, the possible get what reality they have only from their being objects to the divine understanding, which serves as the connection between the world of essences and that of existences. At another, all true essences form one system, the only difference between them as to reality being in degree, and actuality or existence being simply a superior degree of reality. But this is certainly to give existence an internal and necessary relation to essence, even to make it a degree of essence.
It may seem that this review of the contrasting views of Spinoza and Leibniz as to the nature of possibility is an unnecessary statement of a well-worn subject. But there is, as I said in commencing it, a modern application of the discussion. One of the most recent theories as to the nature of judgment, that propounded some years since by Mr. G. E. Moore, and since then accepted and applied by Mr. Russell in his Principles of Mathematics, essentially depends on separating existence from the other relations or predicates asserted in judging, and putting it in a class by itself. A proposition, according to this theory, is a synthesis of concepts; and concepts are all logical subjects, immutable and indestructible quiddities or essences, the relations between which are as immutable as they themselves. "According to the nature of this relation, the proposition is either true or false." But "what kind of relation makes a proposition true, what false, cannot be further defined, but must be immediately recognized." By this refusal to define, one of the difficulties of Leibniz, that of the source of incompatibility of concepts, is avoided, at some expense of logical completeness, to be sure. Existence is one of these concepts, and things exist when they "have a specific relation “to it. All possible objects of thought tore beings; but not all are existences. "This distinction is essential if we are ever to deny the existence of anything. For what does not exist must be something, or it would be meaningless to deny its existence."
This last argument fails to recognize that we may by such denial negatively qualify existence. However, my objection would have no weight for one holding this position, since propositions for him would be relations of entities, quite independent of any knowing mind. These entities, or 'quiddities,' as I called them a moment ago, are also mutually independent, quite like the monads of Leibniz.
Now such a theory as this is really a logical monadology of assort; and the point that I wish to make is that it is exposed to all the antinomies and difficulties which we have found to confront any theory which divides essence from existence, possibility from reality. It is true that by taking refuge in the indefinable it avoids some of Leibniz's difficulties, especially that as to how concepts become incompatible, already mentioned, and those connected with the " sufficient reason." But the connection between essence and existence still remains to be defined and explained. Again, refuge is taken in the indefinable; existence is a concept, and this relation, like all those between concepts, is ultimate, immediately recognizable as true or false. This is mere skirmishing. No theory of judgment can justify its existence which stops at the brute facts which common sense has for ages recognized; and this is just what this theory of concepts does. If it is to make its claims good, it must go on to show some principle of order in the logical relations which it recognizes; and once it does so, I fail to see how it can avoid the self-contradiction which lies at the heart of all such distinctions of the possible from the real, or the essential from the existential.