Critique of Pure Reason

By

Immanuel Kant

CHAPTER III

Section Four

THE IMPOSSIBILITY OF AN ONTOLOGICAL PROOF OF THE EXISTENCE OF GOD

It is evident, from what has been said, that the concept of an absolutely necessary being is a concept of pure reason, that is, a mere idea the objective reality of which is very far from being proved by the fact that reason requires it. For the idea instructs us only in regard to a certain unattainable completeness, and so serves rather to limit the understanding than to extend it to new objects. But we are here faced by what is indeed strange and perplexing, namely, that while the inference from a given existence in general to some absolutely necessary being seems to be both imperative and legitimate, all those conditions under which alone the understanding can form a concept of such a necessity are so many obstacles in the way of our doing so.

In all ages men have spoken of an absolutely necessary being, and in so doing have endeavoured, not so much to understand whether and how a thing of this kind allows even of being thought, but rather to prove its existence. There is, of course, no difficulty in giving a verbal definition of the concept, namely, that it is something the non-existence of which is impossible. But this yields no insight into the conditions A593 B621 which make it necessary to regard the non-existence of a thing as absolutely unthinkable. It is precisely these conditions that we desire to know, in order that we may determine whether or not, in resorting to this concept, we are thinking anything at all. The expedient of removing all those conditions which the understanding indispensably requires in order to regard something as necessary, simply through the introduction of the word unconditioned, is very far from sufficing to show whether I am still thinking anything in the concept of the unconditionally necessary, or perhaps rather nothing at all.

Nay more, this concept, at first ventured upon blindly, and now become so completely familiar, has been supposed to have its meaning exhibited in a number of examples; and on this account all further enquiry into its intelligibility has seemed to be quite needless. Thus the fact that every geometrical proposition, as, for instance, that a triangle has three angles, is absolutely necessary, has been taken as justifying us in speaking of an object which lies entirely outside the sphere of our understanding as if we understood perfectly what it is that we intend to convey by the concept of that object.

All the alleged examples are, without exception, taken from judgments, not from things and their existence. But the unconditioned necessity of judgments is not the same as an absolute necessity of things. The absolute necessity of the judgment is only a conditioned necessity of the thing, or of the predicate in the judgment. The above proposition does not A594 B622 P 502 declare that three angles are absolutely necessary, but that, under the condition that there is a triangle (that is, that a triangle is given), three angles will necessarily be found in it. So great, indeed, is the deluding influence exercised by this logical necessity that, by the simple device of forming an a priori concept of a thing in such a manner as to include existence within the scope of its meaning, we have supposed ourselves to have justified the conclusion that because existence necessarily belongs to the object of this concept -- always under the condition that we posit the thing as given (as existing) -- we are also of necessity, in accordance with the law of identity, required to posit the existence of its object, and that this being is therefore itself absolutely necessary -- and this, to repeat, for the reason that the existence of this being has already been thought in a concept which is assumed arbitrarily and on condition that we posit its object.

If, in an identical proposition, I reject the predicate while retaining the subject, contradiction results; and I therefore say that the former belongs necessarily to the latter. But if we reject subject and predicate alike, there is no contradiction; for nothing is then left that can be contradicted. To posit a triangle, and yet to reject its three angles, is self-contradictory; but there is no contradiction in rejecting the triangle together with its three angles. The same holds true of the concept of an absolutely necessary being. If its existence is rejected, we reject A595 B623 the thing itself with all its predicates; and no question of contradiction can then arise. There is nothing outside it that would then be contradicted, since the necessity of the thing is not supposed to be derived from anything external; nor is there anything internal that would be contradicted, since in rejecting the thing itself we have at the same time rejected all its internal properties. 'God is omnipotent' is a necessary judgment. The omnipotence cannot be rejected if we posit a Deity, that is, an infinite being; for the two concepts are identical. But if we say, 'There is no God', neither the omnipotence nor any other of its predicates is given; they are one and all rejected together with the subject, and there is therefore not the least contradiction in such a judgment.

We have thus seen that if the predicate of a judgment is rejected together with the subject, no internal contradiction P 503 can result and that this holds no matter what the predicate may be. The only way of evading this conclusion is to argue that there are subjects which cannot be removed, and must always remain. That, however, would only be another way of saying that there are absolutely necessary subjects; and that is the very assumption which I have called in question, and the possibility of which the above argument professes to establish. For I cannot form the least concept of a thing which, should it be rejected with all its predicates, leaves behind a A596 B624 contradiction; and in the absence of contradiction I have, through pure a priori concepts alone, no criterion of impossibility.

Notwithstanding all these general considerations, in which every one must concur, we may be challenged with a case which is brought forward as proof that in actual fact the contrary holds, namely, that there is one concept, and indeed only one, in reference to which the not-being or rejection of its object is in itself contradictory, namely, the concept of the ens realissimum. It is declared that it possesses all reality, and that we are justified in assuming that such a being is possible (the fact that a concept does not contradict itself by no means proves the possibility of its object: but the contrary assertion I am for the moment willing to allow). Now [the argument proceeds] 'all reality' includes existence; existence is therefore contained in the concept of a thing that is possible. If, then, this thing is rejected, the internal possibility of the thing is A597 B625 rejected -- which is self-contradictory.

My answer is as follows. There is already a contradiction in introducing the concept of existence -- no matter under what title it may be disguised -- into the concept of a thing which we profess to be thinking solely in reference to its possibility. If that be allowed as legitimate, a seeming victory has been won; but in actual fact nothing at all is said: the assertion is a mere tautology. We must ask: Is the proposition that this or that thing (which, whatever it may be, is allowed as possible) exists, an analytic or a synthetic proposition? If it is analytic, the assertion of the existence of the thing adds nothing to the thought of the thing; but in that case either the thought, which is in us, is the thing itself, or we have presupposed an existence as belonging to the realm of the possible, and have then, on that pretext, inferred its existence from its internal possibility -- which is nothing but a miserable tautology. The word 'reality', which in the concept of the thing sounds other than the word 'existence' in the concept of the predicate, is of no avail in meeting this objection. For if all positing (no matter what it may be that is posited) is entitled reality, the thing with all its predicates is already posited in the concept of the subject, and is assumed as actual; and in the predicate this is merely repeated. But if, on the other hand, A598 B626 we admit, as every reasonable person must, that all existential propositions are synthetic, how can we profess to maintain that the predicate of existence cannot be rejected without contradiction? This is a feature which is found only in analytic propositions, and is indeed precisely what constitutes their analytic character.

I should have hoped to put an end to these idle and fruitless disputations in a direct manner, by an accurate determination of the concept of existence, had I not found that the illusion which is caused by the confusion of a logical with a real predicate (that is, with a predicate which determines a thing) is almost beyond correction. Anything we please can be made to serve as a logical predicate; the subject can even be predicated of itself; for logic abstracts from all content. But a determining predicate is a predicate which is added to the concept of the subject and enlarges it. Consequently, it must not be already contained in the concept.

'Being' is obviously not a real predicate; that is, it is not a concept of something which could be added to the concept of a thing. It is merely the positing of a thing, or of certain determinations, as existing in themselves. Logically, it is merely the copula of a judgment. The proposition, 'God is omnipotent', P 505 contains two concepts, each of which has its object -- God and omnipotence. The small word 'is' adds no new predicate, but only serves to posit the predicate in its relation to the subject. If, A599 B627 now, we take the subject (God) with all its predicates (among which is omnipotence), and say 'God is', or 'There is a God', we attach no new predicate to the concept of God, but only posit the subject in itself with all its predicates, and indeed posit it as being an object that stands in relation to my concept. The content of both must be one and the same; nothing can have been added to the concept, which expresses merely what is possible, by my thinking its object (through the expression 'it is') as given absolutely. Otherwise stated, the real contains no more than the merely possible. A hundred real thalers do not contain the least coin more than a hundred possible thalers. For as the latter signify the concept, and the former the object and the positing of the object, should the former contain more than the latter, my concept would not, in that case, express the whole object, and would not therefore be an adequate concept of it. My financial position is, however, affected very differently by a hundred real thalers than it is by the mere concept of them (that is, of their possibility). For the object, as it actually exists, is not analytically contained in my concept, but is added to my concept (which is a determination of my state) synthetically; and yet the conceived hundred thalers are not themselves in the least increased through thus acquiring existence outside my concept.

By whatever and by however many predicates we may A600 B628 think a thing -- even if we completely determine it -- we do not make the least addition to the thing when we further declare that this thing is. Otherwise, it would not be exactly the same thing that exists, but something more than we had thought in the concept; and we could not, therefore, say that the exact object of my concept exists. If we think in a thing every feature of reality except one, the missing reality is not added by my saying that this defective thing exists. On the contrary, it exists with the same defect with which I have thought it, since otherwise what exists would be something different from what I thought. When, therefore, I think a being as the supreme reality, without any defect, the question still remains whether P 506 it exists or not. For though, in my concept, nothing may be lacking of the possible real content of a thing in general, something is still lacking in its relation to my whole state of thought, namely, [in so far as I am unable to assert] that knowledge of this object is also possible a posteriori. And here we find the source of our present difficulty. Were we dealing with an object of the senses, we could not confound the existence of the thing with the mere concept of it. For through the concept the object is thought only as conforming to the universal conditions of possible empirical knowledge in general, whereas through its existence it is thought as belonging to the context A601 B629 of experience as a whole. In being thus connected with the content of experience as a whole, the concept of the object is not, however, in the least enlarged; all that has happened is that our thought has thereby obtained an additional possible perception. It is not, therefore, surprising that, if we attempt to think existence through the pure category alone, we cannot specify a single mark distinguishing it from mere possibility.

Whatever, therefore, and however much, our concept of an object may contain, we must go outside it, if we are to ascribe existence to the object. In the case of objects of the senses, this takes place through their connection with some one of our perceptions, in accordance with empirical laws. But in dealing with objects of pure thought, we have no means whatsoever of knowing their existence, since it would have to be known in a completely a priori manner. Our consciousness of all existence (whether immediately through perception, or mediately through inferences which connect something with perception) belongs exclusively to the unity of experience; any [alleged] existence outside this field, while not indeed such as we can declare to be absolutely impossible, is of the nature of an assumption which we can never be in a position to justify.

The concept of a supreme being is in many respects a very useful idea; but just because it is a mere idea, it is altogether incapable, by itself alone, of enlarging our knowledge in regard to what exists. It is not even competent to enlighten us A602 B630 as to the possibility of any existence beyond that which is known in and through experience. The analytic criterion of P 507 possibility, as consisting in the principle that bare positives (realities) give rise to no contradiction, cannot be denied to it. But since the realities are not given to us in their specific characters; since even if they were, we should still not be in a position to pass judgment; since the criterion of the possibility of synthetic knowledge is never to be looked for save in experience, to which the object of an idea cannot belong, the connection of all real properties in a thing is a synthesis, the possibility of which we are unable to determine a priori. And thus the celebrated Leibniz is far from having succeeded in what he plumed himself on achieving -- the comprehension a priori of the possibility of this sublime ideal being.

The attempt to establish the existence of a supreme being by means of the famous ontological argument of Descartes is therefore merely so much labour and effort lost; we can no more extend our stock of [theoretical] insight by mere ideas, than a merchant can better his position by adding a few noughts to his cash account.

CHAPTER III A603 B631

Section Five

THE IMPOSSIBILITY OF A COSMOLOGICAL PROOF OF THE EXISTENCE OF GOD

To attempt to extract from a purely arbitrary idea the existence of an object corresponding to it is a quite unnatural procedure and a mere innovation of scholastic subtlety. Such an attempt would never have been made if there had not been antecedently, on the part of our reason,the need to assume as a basis of existence in general something necessary (in which our regress may terminate); and if, since this necessity must be unconditioned and certain a priori, reason had not, in consequence, been forced to seek a concept which would satisfy, if possible, such a demand, and enable us to know an existence in a completely a priori manner. Such a concept was supposed to have been found in the idea of an ens realissimum; and that P 508 idea was therefore used only for the more definite knowledge of that necessary being, of the necessary existence of which we were already convinced, or persuaded, on other grounds. This natural procedure of reason was, however, concealed from view, and instead of ending with this concept, the attempt was made to begin with it, and so to deduce from it that necessity of existence which it was only fitted to supplement. A604 B632 Thus arose the unfortunate ontological proof, which yields satisfaction neither to the natural and healthy understanding nor to the more academic demands of strict proof.

The cosmological proof, which we are now about to examine, retains the connection of absolute necessity with the highest reality, but instead of reasoning, like the former proof, from the highest reality to necessity of existence, it reasons from the previously given unconditioned necessity of some being to the unlimited reality of that being. It thus enters upon a course of reasoning which, whether rational or only pseudo- rational, is at any rate natural, and the most convincing not only for common sense but even for speculative understanding. It also sketches the first outline of all the proofs in natural theology, an outline which has always been and always will be followed, however much embellished and disguised by superfluous additions. This proof, termed by Leibniz the proof a contingentia mundi, we shall now proceed to expound and examine.

It runs thus: If anything exists, an absolutely necessary being must also exist. Now I, at least, exist. Therefore an absolutely necessary being exists. The minor premiss contains an experience, the major premiss the inference from there A605 B633 being any experience at all to the existence of the necessary. The proof therefore really begins with experience, and is not wholly a priori or ontological. For this reason, and because the object of all possible experience is called the world, it is entitled the cosmological proof. P 508 Since, in dealing with the objects P 509 of experience, the proof abstracts from all special properties through which this world may differ from any other possible world, the title also serves to distinguish it from the physico- theological proof, which is based upon observations of the particular properties of the world disclosed to us by our senses.

The proof then proceeds as follows: The necessary being can be determined in one way only, that is, by one out of each possible pair of opposed predicates. It must therefore be completely determined through its own concept. Now there is only one possible concept which determines a thing completely a priori, namely, the concept of the ens realissimum. The concept of the ens realissimum is therefore the only concept A606 B634 through which a necessary being can be thought. In other words, a supreme being necessarily exists.

In this cosmological argument there are combined so many pseudo-rational principles that speculative reason seems in this case to have brought to bear all the resources of its dialectical skill to produce the greatest possible transcendental illusion. The testing of the argument may meantime be postponed while we detail in order the various devices whereby an old argument is disguised as a new one, and by which appeal is made to the agreement of two witnesses, the one with credentials of pure reason and the other with those of experience. In reality the only witness is that which speaks in the name of pure reason; in the endeavour to pass as a second witness it merely changes its dress and voice. In order to lay a secure foundation for itself, this proof takes its stand on experience, and thereby makes profession of being distinct from the ontological proof, which puts its entire trust in pure a priori concepts. But the cosmological proof uses this experience only for a single step in the argument, namely, to conclude the existence of a necessary being. What properties this being may have, the empirical premiss cannot tell us. Reason therefore abandons experience altogether, and endeavours to discover from mere concepts what properties an absolutely A607 B635 necessary being must have, that is, which among all possible things contains in itself the conditions (requisita) essential to absolute necessity. Now these, it is supposed, are nowhere to be found save in the concept of an ens realissimum; and the conclusion is therefore drawn, that the ens realissimum is the P 510 absolutely necessary being. But it is evident that we are here presupposing that the concept of the highest reality is completely adequate to the concept of absolute necessity of existence; that is, that the latter can be inferred from the former. Now this is the proposition maintained by the ontological proof; it is here being assumed in the cosmological proof, and indeed made the basis of the proof; and yet it is an assumption with which this latter proof has professed to dispense. For absolute necessity is an existence determined from mere concepts. If I say, the concept of the ens realissimum is a concept, and indeed the only concept, which is appropriate and adequate to necessary existence, I must also admit that necessary existence can be inferred from this concept. Thus the so- called cosmological proof really owes any cogency which it may have to the ontological proof from mere concepts. The appeal to experience is quite superfluous; experience may perhaps lead us to the concept of absolute necessity, but is unable to demonstrate this necessity as belonging to any determinate thing. For immediately we endeavour to do so, we must abandon all experience and search among pure concepts to discover whether any one of them contains the conditions of the possibility of an absolutely necessary being. If A608 B636 in this way we can determine the possibility of a necessary being, we likewise establish its existence. For what we are then saying is this: that of all possible beings there is one which carries with it absolute necessity, that is, that this being exists with absolute necessity.

Fallacious and misleading arguments are most easily detected if set out in correct syllogistic form. This we now proceed to do in the instance under discussion.

If the proposition, that every absolutely necessary being is likewise the most real of all beings, is correct (and this is the nervus probandi of the cosmological proof), it must, like all affirmative judgments, be convertible, at least per accidens. It therefore follows that some entia realissima are likewise absolutely necessary beings. But one ens realissimum is in no respect different from another, and what is true of some under this concept is true also of all. In this case, therefore, I can convert the proposition simpliciter, not only per accidens, and say that every ens realissimum is a necessary being. But P 511 since this proposition is determined from its a priori concepts alone, the mere concept of the ens realissimum must carry with it the absolute necessity of that being; and this is precisely what the ontological proof has asserted and what the cosmological proof has refused to admit, although the conclusions A609 B637 of the latter are indeed covertly based on it.

Thus the second path upon which speculative reason enters in its attempt to prove the existence of a supreme being is not only as deceptive as the first, but has this additional defect, that it is guilty of an ignoratio elenchi. It professes to lead us by a new path, but after a short circuit brings us back to the very path which we had deserted at its bidding.

I have stated that in this cosmological argument there lies hidden a whole nest of dialectical assumptions, which the transcendental critique can easily detect and destroy. These deceptive principles I shall merely enumerate, leaving to the reader, who by this time will be sufficiently expert in these matters, the task of investigating them further, and of refuting them.

We find, for instance, (1) the transcendental principle whereby from the contingent we infer a cause. This principle is applicable only in the sensible world; outside that world it has no meaning whatsoever. For the mere intellectual concept of the contingent cannot give rise to any synthetic proposition, such as that of causality. The principle of causality has no meaning and no criterion for its application save only in the sensible world. But in the cosmological proof it is precisely in order to enable us to advance beyond the sensible world that it is employed. (2) The inference to a first cause, from the A610 B638 impossibility of an infinite series of causes, given one after the other, in the sensible world. The principles of the employment of reason do not justify this conclusion even within the world of experience; still less beyond this world in a realm into which this series can never be extended. (3) The unjustified self-satisfaction of reason in respect of the completion of this series. The removal of all the conditions without which no concept of necessity is possible is taken by reason to be a completion of the concept of the series, on the ground that we can then conceive nothing further. (4) The confusion between the P 512 logical possibility of a concept of all reality united into one (without inner contradiction) and the transcendental possibility of such a reality. In the case of the latter there is needed a principle to establish the practicability of such a synthesis, a principle which itself, however, can apply only to the field of possible experiences -- etc.

The procedure of the cosmological proof is artfully designed to enable us to escape having to prove the existence of a necessary being a priori through mere concepts. Such proof would require to be carried out in the ontological manner, and that is an enterprise for which we feel ourselves to be altogether incompetent. Accordingly, we take as the starting-point of our inference an actual existence (an experience in general), and advance, in such manner as we can, to some absolutely necessary condition of this existence. We have then no need to show the possibility of this condition. For if it has been proved to exist, A611 B639 the question as to its possibility is entirely superfluous. If now we want to determine more fully the nature of this necessary being, we do not endeavour to do so in the manner that would be really adequate, namely, by discovering from its concept the necessity of its existence. For could we do that, we should be in no need of an empirical starting-point. No, all we seek is the negative condition (conditio sine qua non), without which a being would not be absolutely necessary. And in all other kinds of reasoning from a given consequence to its ground this would be legitimate; but in the present case it unfortunately happens that the condition which is needed for absolute necessity is only to be found in one single being. This being must therefore contain in its concept all that is required for absolute necessity, and consequently it enables me to infer this absolute necessity a priori. I must therefore be able also to reverse the inference, and to say: Anything to which this concept (of supreme reality) applies is absolutely necessary. If I cannot make this inference (as I must concede, if I am to avoid admitting the ontological proof), I have come to grief in the new way that I have been following, and am back again at my starting-point. The concept of the supreme being satisfies all questions a priori which can be raised regarding the inner determinations of a thing, and is therefore an ideal that is quite unique, in that the A612 B640 concept, while universal, also at the same time designates an P 513 individual as being among the things that are possible. But it does not give satisfaction concerning the question of its own existence -- though this is the real purpose of our enquiries -- and if anyone admitted the existence of a necessary being but wanted to know which among all [existing] things is to be identified with that being, we could not answer: "This, not that. is the necessary being."

We may indeed be allowed to postulate the existence of an all-sufficient being, as the cause of all possible effects, with a view to lightening the task of reason in its search for the unity of the grounds of explanation. But in presuming so far as to say that such a being necessarily exists, we are no longer giving modest expression to an admissible hypothesis, but are confidently laying claim to apodeictic certainty. For the knowledge of what we profess to know as absolutely necessary must itself carry with it absolute necessity.

The whole problem of the transcendental ideal amounts to this: either, given absolute necessity, to find a concept which possesses it, or, given the concept of something, to find that something to be absolutely necessary. If either task be possible, so must the other; for reason recognises that only as absolutely necessary which follows of necessity from its concept. But both tasks are quite beyond our utmost efforts to satisfy our A613 B641 understanding in this matter; and equally unavailing are all attempts to induce it to acquiesce in its incapacity.

Unconditioned necessity, which we so indispensably require as the last bearer of all things, is for human reason the veritable abyss. Eternity itself, in all its terrible sublimity, as depicted by a Haller, is far from making the same overwhelming impression on the mind; for it only measures the duration of things, it does not support them. We cannot put aside, and yet also cannot endure the thought, that a being, which we represent to ourselves as supreme amongst all possible beings, should, as it were, say to itself: 'I am from eternity to eternity, and outside me there is nothing save what is through my will, but whence then am I? ' All support here fails us; and the greatest perfection, no less than the least perfection, is unsubstantial and baseless for the merely speculative reason, which P 514 makes not the least effort to retain either the one or the other, and feels indeed no loss in allowing them to vanish entirely.

Many forces in nature, which manifest their existence through certain effects, remain for us inscrutable; for we cannot track them sufficiently far by observation. Also, the transcendental object lying at the basis of appearances (and with it the reason why our sensibility is subject to certain supreme conditions rather than to others) is and remains for us inscrutable. A614 B642 The thing itself is indeed given, but we can have no insight into its nature. But it is quite otherwise with an ideal of pure reason; it can never be said to be inscrutable. For since it is not required to give any credentials of its reality save only the need on the part of reason to complete all synthetic unity by means of it; and since, therefore, it is in no wise given as thinkable object, it cannot be inscrutable in the manner in which an object is. On the contrary it must, as a mere idea, find its place and its solution in the nature of reason, and must therefore allow of investigation. For it is of the very essence of reason that we should be able to give an account of all our concepts, opinions, and assertions, either upon objective or, in the case of mere illusion, upon subjective grounds.