Kant's Theory of Knowledge

by H. A. Prichard

The examples of mathematics and physics suggest, according to Kant, that metaphysics may require a similar revolution of standpoint, the lack of which will account for its past failure. An attempt should therefore be made to introduce such a change into metaphysics. The change is this. Hitherto it has been assumed that our knowledge must conform to objects. This assumption is the real cause of the failure to extend our knowledge a priori, for it limits thought to the analysis of conceptions, which can only yield tautological judgements. Let us therefore try the effect of assuming that objects must conform to our knowledge. Herein lies the Copernican revolution. We find that this reversal of the ordinary view of the relation of objects to the mind enables us for the first time to understand the possibility of a priori synthetic judgements, and even to demonstrate certain laws which lie at the basis of nature, e. g. the law of causality. It is true that the reversal also involves the surprising consequence that our faculty of knowledge is incapable of dealing with the objects of metaphysics proper, viz. God, freedom, and immortality, for the assumption limits our knowledge to objects of possible experience. But this very consequence, viz. the impossibility of metaphysics, serves to test and vindicate the assumption. For the view that our knowledge conforms to objects as things in themselves leads us into an insoluble contradiction when we go on, as we must, to seek for the unconditioned; while the assumption that objects must, as phenomena, conform to our way of representing them, removes the contradiction[13]. Further, though the assumption leads to the denial of speculative knowledge in the sphere of metaphysics, it is still possible that reason in its practical aspect may step in to fill the gap. And the negative result of the assumption may even have a positive value. For if, as is the case, the moral reason, or reason in its practical aspect, involves certain postulates concerning God, freedom, and immortality, which are rejected by the speculative reason, it is important to be able to show that these objects fall beyond the scope of the speculative reason. And if we call reliance on these postulates, as being presuppositions of morality, faith, we may say that knowledge must be abolished to make room for faith.

This answer to the main problem, given in outline in the Preface, is undeniably plausible. Yet examination of it suggests two criticisms which affect Kant's general position.

In the first place, the parallel of mathematics which suggests the 'Copernican' revolution does not really lead to the results which Kant supposes. Advance in mathematics is due to the adoption not of any conscious assumption but of a certain procedure, viz. that by which we draw a figure and thereby see the necessity of certain relations within it. To preserve the parallel, the revolution in metaphysics should have consisted in the adoption of a similar procedure, and advance should have been made dependent on the application of an at least quasi-mathematical method to the objects of metaphysics. Moreover, since these objects are God, freedom, and immortality, the conclusion should have been that we ought to study God, freedom, and immortality by somehow constructing them in perception and thereby gaining insight into the necessity of certain relations. Success or failure in metaphysics would therefore consist simply in success or failure to see the necessity of the relations involved. Kant, however, makes the condition of advance in metaphysics consist in the adoption not of a method of procedure but of an assumption, viz. that objects conform to the mind. And it is impossible to see how this assumption can assist what, on Kant's theory, it ought to have assisted, viz. the study of God, freedom, and immortality, or indeed the study of anything. In geometry we presuppose that individual objects conform to the universal rules of relation which we discover. Now suppose we describe a geometrical judgement, e. g. that two straight lines cannot enclose a space, as a mental law, because we are bound to think it true. Then we may state the presupposition by saying that objects, e. g. individual pairs of straight lines, must conform to such a mental law. But the explicit recognition of this presupposition and the conscious assertion of it in no way assist the solution of particular geometrical problems. The presupposition is really a condition of geometrical thinking at all. Without it there is no geometrical thinking, and the recognition of it places us in no better position for the study of geometrical problems. Similarly, if we wish to think out the nature of God, freedom, and immortality, we are not assisted by assuming that these objects must conform to the laws of our thinking. We must presuppose this conformity if we are to think at all, and consciousness of the presupposition puts us in no better position. What is needed is an insight similar to that which we have in geometry, i. e. an insight into the necessity of the relations under consideration such as would enable us to see, for example, that being a man, as such, involves living for ever.

Kant has been led into the mistake by a momentary change in the meaning given to 'metaphysics'. For the moment he is thinking of metaphysics, not as the inquiry concerned with God, freedom, and immortality, but as the inquiry which has to deal with the problem as to how we can know a priori. This problem is assisted, at any rate prima facie, by the assumption that things must conform to the mind. And this assumption can be said to be suggested by mathematics, inasmuch as the mathematician presupposes that particular objects must correspond to the general rules discovered by the mind. From this point of view Kant's only mistake, if the parallelism is to be maintained, is that he takes for an assumption which enables the mathematician to advance a metaphysical presupposition of the advance, on which the mathematician never reflects, and awareness of which would in no way assist his mathematics.

In the second place the 'Copernican' revolution is not strictly the revolution which Kant supposes it to be. He speaks as though his aim is precisely to reverse the ordinary view of the relation of the mind to objects. Instead of the mind being conceived as having to conform to objects, objects are to be conceived as having to conform to the mind. But if we consider Kant's real position, we see that these views are only verbally contrary, since the word object refers to something different in each case. On the ordinary view objects are something outside the mind, in the sense of independent of it, and the ideas, which must conform to objects, are something within the mind, in the sense of dependent upon it. The conformity then is of something within the mind to something outside it. Again, the conformity means that one of the terms, viz. the object, exists first and that then the other term, the idea, is fitted to or made to correspond to it. Hence the real contrary of this view is that ideas, within the mind, exist first and that objects outside the mind, coming into existence afterwards, must adapt themselves to the ideas. This of course strikes us as absurd, because we always think of the existence of the object as the presupposition of the existence of the knowledge of it; we do not think the existence of the knowledge as the presupposition of the existence of the object. Hence Kant only succeeds in stating the contrary of the ordinary view with any plausibility, because in doing so he makes the term object refer to something which like 'knowledge' is within the mind. His position is that objects within the mind must conform to our general ways of knowing. For Kant, therefore, the conformity is not between something within and something without the mind, but between two realities within the mind, viz. the individual object, as object of perception, i. e. a phenomenon, and our general ways of perceiving and thinking. But this view is only verbally the contrary of the ordinary view, and consequently Kant does not succeed in reversing the ordinary view that we know objects independent of or outside the mind, by bringing our ideas into conformity with them. In fact, his conclusion is that we do not know this object, i. e. the thing in itself, at all. Hence his real position should be stated by saying not that the ordinary view puts the conformity between mind and things in the wrong way, but that we ought not to speak of conformity at all. For the thing in itself being unknowable, our ideas can never be made to conform to it. Kant then only reaches a conclusion which is apparently the reverse of the ordinary view by substituting another object for the thing in itself, viz. the phenomenon or appearance of the thing in itself to us.

Further, this second line of criticism, if followed out, will be found to affect his statement of the problem as well as that of its solution. It will be seen that the problem is mis-stated, and that the solution offered presupposes it to be mis-stated. His statement of the problem takes the form of raising a difficulty which the existence of a priori knowledge presents to the ordinary view, according to which objects are independent of the mind, and ideas must be brought into conformity with them. In a synthetic a priori judgement we claim to discover the nature of certain objects by an act of our thinking, and independently of actual experience of them. Hence if a supporter of the ordinary view is asked to justify the conformity of this judgement or idea with the objects to which it relates, he can give no answer. The judgement having ex hypothesi been made without reference to the objects, the belief that the objects must conform to it is the merely arbitrary supposition that a reality independent of the mind must conform to the mind's ideas. But Kant, in thus confining the difficulty to a priori judgements, implies that empirical judgements present no difficulty to the ordinary view; since they rest upon actual experience of the objects concerned, they are conformed to the objects by the very process through which they arise. He thereby fails to notice that empirical judgements present a precisely parallel difficulty. It can only be supposed that the conformity of empirical judgements to their objects is guaranteed by the experience upon which they rest, if it be assumed that in experience we apprehend objects as they are. But our experience or perception of individual objects is just as much mental as the thinking which originates a priori judgements. If we can question the truth of our thinking, we can likewise question the truth of our perception. If we can ask whether our ideas must correspond to their objects, we can likewise ask whether our perceptions must correspond to them. The problem relates solely to the correspondence between something within the mind and something outside it; it applies equally to perceiving and thinking, and concerns all judgements alike, empirical as well as a priori. Kant, therefore, has no right to imply that empirical judgements raise no problem, if he finds difficulty in a priori judgements. He is only able to draw a distinction between them, because, without being aware that he is doing so, he takes account of the relation of the object to the subject in the case of an a priori judgement, while in the case of an empirical judgement he ignores it. In other words, in dealing with the general connexion between the qualities of an object, he takes into account the fact that we are thinking it, but, in dealing with the perception of the coexistence of particular qualities of an object, he ignores the fact that we are perceiving it. Further, that the real problem concerns all synthetic judgements alike is shown by the solution which he eventually reaches. His conclusion turns out to be that while both empirical and a priori judgements are valid of phenomena, they are not valid of things in themselves; i. e. that of things in themselves we know nothing at all, not even their particular qualities. Since, then, his conclusion is that even empirical judgements are not valid of things in themselves, it shows that the problem cannot be confined to a priori judgements, and therefore constitutes an implicit criticism of his statement of the problem.

Must there not, however, be some problem peculiar to a priori judgements? Otherwise why should Kant have been led to suppose that his problem concerned them only? Further consideration will show that there is such a problem, and that it was only owing to the mistake indicated that Kant treated this problem as identical with that of which he actually offered a solution. In the universal judgements of mathematics we apprehend, as we think, general rules of connexion which must apply to all possible cases. Such judgements, then, presuppose a conformity between the connexions which we discover and all possible instances. Now Kant's treatment of this conformity as a conformity between our ideas and things has two implications. In the first place, it implies, as has been pointed out, that relation to the subject, as thinking, is taken into account in the case of the universal connexion, and that relation to the subject, as perceiving, is ignored in the case of the individual thing. In the second place, it implies that what is related to the subject as the object of its thought must be subjective or mental; that because we have to think the general connexion, the connexion is only our own idea, the conformity of things to which may be questioned. But the treatment, to be consistent, should take account of relation to the subject in both cases or in neither. If the former alternative be accepted, then the subjective character attributed by Kant in virtue of this relation to what is object of thought, and equally attributable to what is object of perception, reduces the problem to that of the conformity in general of all ideas, including perceptions, within the mind to things outside it; and this problem does not relate specially to a priori judgements. To discover the problem which relates specially to them, the other alternative must be accepted, that of ignoring relation to the subject in both cases. The problem then becomes 'What renders possible or is presupposed by the conformity of individual things to certain laws of connexion?' And, inasmuch as to deny the conformity is really to deny that there are laws of connexion,[14] the problem reduces itself to the question, 'What is the presupposition of the existence of definite laws of connexion in the world?' And the only answer possible is that reality is a system or a whole of connected parts, in other words, that nature is uniform. Thus it turns out that the problem relates to the uniformity of nature, and that the question 'How are a priori synthetic judgements possible?' has in reality nothing to do with the problem of the relation of reality to the knowing subject, but is concerned solely with the nature of reality.

Further, it is important to see that the alternative of ignoring relation to the subject is the right one, not only from the point of view of the problem peculiar to a priori judgements, but also from the point of view of the nature of knowledge in general. Perceiving and thinking alike presuppose that reality is immediately object of the mind, and that the act of apprehension in no way affects or enters into the nature of what we apprehend about reality. If, for instance, I assert on the strength of perception that this table is round, I imply that I see the table, and that the shape which I judge it to have is not affected by the fact that I am perceiving it; for I mean that the table really is round. If some one then convinces me that I have made a mistake owing to an effect of foreshortening, and that the table is really oval, I amend my assertion, not by saying that the table is round but only to my apprehension, but by saying that it looks round. Thereby I cease to predicate roundness of the table altogether; for I mean that while it still looks round, it is not really so. The case of universal judgements is similar. The statement that a straight line is the shortest distance between its extremities means that it really is so. The fact is presupposed to be in no way altered by our having apprehended it. Moreover, reality is here just as much implied to be directly object of the mind as it is in the case of the singular judgement. Making the judgement consists, as we say, in seeing the connexion between the direction between two points and the shortest distance between them. The connexion of real characteristics is implied to be directly object of thought.[16] Thus both perceiving and thinking presuppose that the reality to which they relate is directly object of the mind, and that the character of it which we apprehend in the resulting judgement is not affected or altered by the fact that we have had to perceive or conceive the reality.[17]

Kant in the formulation of his problem implicitly admits this presupposition in the case of perception. He implies that empirical judgements involve no difficulty, because they rest upon the perception or experience of the objects to which they relate. On the other hand, he does not admit the presupposition in the case of conception, for he implies that in a priori judgements we are not confronted with reality but are confined to our own ideas. Hence we ought to ask why Kant is led to adopt an attitude in the latter case which he does not adopt in the former. The answer appears to be twofold. In the first place, there is an inveterate tendency to think of universals, and therefore of the connexions between them, as being not objective realities[18] but mere ideas. In other words, we tend to adopt the conceptualist attitude, which regards individuals as the only reality, and universals as mental fictions. In consequence, we are apt to think that while in perception, which is of the individual, we are confronted by reality, in universal judgements, in which we apprehend connexions between universals, we have before us mere ideas. Kant may fairly be supposed to have been unconsciously under the influence of this tendency. In the second place, we apprehend a universal connexion by the operation of thinking. Thinking is essentially an activity; and since activity in the ordinary sense in which we oppose action to knowledge originates something, we tend to think of the activity of thinking as also originating something, viz. that which is our object when we think. Hence, since we think of what is real as independent of us and therefore as something which we may discover but can in no sense make, we tend to think of the object of thought as only an idea. On the other hand, what is ordinarily called perception, though it involves the activity of thinking, also involves an element in respect of which we are passive. This is the fact pointed to by Kant's phrase 'objects are given in perception'. In virtue of this passive element we are inclined to think that in perception we simply stand before the reality in a passive attitude. The reality perceived is thought to be, so to say, there, existing independently of us; relation to the subject is unnoticed because of our apparently wholly passive attitude. At times, and especially when he is thinking of the understanding as a faculty of spontaneity, Kant seems to have been under the influence of this second tendency.

The preceding summary of the problem of the Critique represents the account given in the two Prefaces and the Introduction. According to this account, the problem arises from the unquestioned existence of a priori knowledge in mathematics and physics and the problematic existence of such knowledge in metaphysics, and Kant's aim is to determine the range within which a priori knowledge is possible. Thus the problem is introduced as relating to a priori knowledge as such, no distinction being drawn between its character in different cases. Nevertheless the actual discussion of the problem in the body of the Critique implies a fundamental distinction between the nature of a priori knowledge in mathematics and its nature in physics, and in order that a complete view of the problem may be given, this distinction must be stated.