the problem of knowledge, the fundamental peculiarity of cognition In overlooked. In all cognition, strictly so-called, there is involved a certain synthesis or relation of parts of a characteristic nature, and if we attempt to discuss this synthesis as though it were in itself but one of the facts forming the matter of knowledge, we are driven to regard this relation as being of the quite external kind discovered by observation among matters of knowledge. The difficult of reconciling the two views is that which gives rise to much of the obscurity in Locke's treatment of the theory of knowledge; in Hume the effort to 1dent1fy them, and to explain the synthesis which is essential to cogn1t1on as merely the accidental result of external relations among the elements of conscious experience, appears w1th the utmost clearness, and gives the keynote of all h1s philosophical work. The final perplexity, concealed by various forms of expression, comes forward at the close of the Treahse as absolutely unsolved, and leads Hume, as will be pointed out, to a truly remarkable confession of the weakness of h1s own s stem.

While, then, the general idea of a theory of knowledge as based upon psy cholog1cal analysis is the groundwork of the Treatise, It is a particular consequence of th1s idea that furnishes to Hume the characteristic criterion applied bv him to all philosophical questions. If the relations involved in the fact of cognition are only those discoverable by observation of any particular portion of known experience, then such relations are quite external and contingent. The only necessary relation which can be discovered in a given fact of experience is that of no11-contrad1ct1on (z.e. purely formal); the thing must be what it is, and cannot be conceived as having qualities contradictory of its nature. The universal test, therefore, of any supposed philosophical prmciple is the possibility or impossibility of imagining Its contradictory. All our knowledge is but the sum of our conscious experience, and is consequently material for imagination. “ Let us f1x our attention out of ourselves as much as possible; let us chase our imagination to the heavens or to the utmost l1mits of the universe; we never really advance a step beyond ourselves, nor can conceive any k1nd of existence, but those perceptions which haye appeared in that narrow compass. This IS the 11n1verse of the 1mag1nat1on, nor have we any 1dea but what is there produced." (Works, ed. of 1854, 1. 93, cf. i. 107)

The course of Hume's work follows immediately from his fundamental principle, and the several divisions of the treatise, so far as the theoretical portions are concerned, are but 1ts logical consequences The first part of the first book contains a brief statement of the contents of mmd, a description of all that observation Cdfl discover 1n conscious experience. The second part deals with those judgments which rest upon the formal elements of experience, space and time. The third part discusses the principle of real connexion amon the elements of experience, the relation of cause and effect The fourth part is virtually a consideration of the ultimate significance of th1s conscious experience, of the place it is supposed to occupy in the universe of existence, in other words, of the relat|o11s between the conscious experience of an individual m1nd as disclosed to observation and the supposed realities of self and external things. urst part Hume gives h1s own statement of the s cho ln the p ylogical

foundations of his theory. Viewing the contents of n11nd as matter of experience, he can discover among them only

?;7m one d1st1nct1on, a distinction expressed by the terms

Pressio” 1mQresswns and ideas. Ideas are secondary in naturc, copies of data supplied we know not whence. All that appears 1n conscious experience as primary, as a11sing from some unknown ca11se, and therefore relatively as or1g1nal, Hume designates by the term impress um, and claims to imply by s11ch term no theory whatsoever as to the origin of th1s portion of experience. There is simply the fact of conscious experience, ultimate and inexplicable. Ioreover, if we remain faithful to the fundamental conception that the contents of the m1nd are merely matters of experience, It is evident 1n the first place that as inipressions are strictly individual, ideas also 1nust be strictly particular, and in the second place that the faculties of combining, d1scr1m1nat1ng, abstracting and judging, h1ch Locke had admitted, are merely expressions for particular modes of haying mental experience, 1 e. are modifications of conceding (cf 1 128 n., 137. 192). By this theory, Hume IS freed from all the problems of abstraction and judgment. A comparative judgment 1s simplified into an isolated perception of a peculiar form, and a series of s11n1lar facts are grouped under a single symbol, representing a particular perception, and only by the accident of custom treated as universal (see 1. 37, 38, 100).

Such, Ill substance, is Hume's restatement of Locke's empirical view Conscious experience consists of isolated states, each of which lb to be regarded as a fact and IS related to others in a q111te external fashion. It remains to be seen how knowledge can be explained on such a basis; but, before proceeding to sketch Hume's answer to this question, It IS necessary to draw attention, first, to the peculiar dey ice invariably resorted to by him when any exception to his general prmciple that ideas are secondary copies of impressions presents itself, and, secondly, to the nature of the substitute offered by him for that perception of relations or synthesis which even 1n Locke's confused statements had appeared as the essence of cognition. Whenever Hume finds it impossible to recognize in an idea the mere copy of a particular impression, he introduces the phrase “ manner of conceiving.” I'hus general or abstract ideas are merely copies of a particular impression conceived in a particular manner. The ideas of space and time, as will presently be pomted out, are copies of impressions conceived in a particular manner. The idea of necessary connexion is merely the reproduction of an impression which the mind feels itself co1npelled to conceive in a particular manner. Such a fashion of disguismg difficulties points, not only to an inconsistency in Hume's theory as stated by himself, but to the initial error upon which it proceeds; for these perplexities are but the consequences of the doctrine that cognition is to be explained on the basis of particular perceptions. These external relations are, in fact, what Hume describes as the natural bonds of connexion among ideas, and, regarded subjectively as principles of association among the facts of 1nental experience, they for1n the substitute he offers for the synthesis implied in knowledge. 'Ihese principles of association determine the imagination to C0mbilI€ 1deas in various modes, and by th1s mechanical combination Hume, for a time, endeavoured to explain what are otherwise called judgments of relation. It was impossible, however, for h1m to carry out this view consistently. The only combination which, even in appearance, could be explained satisfactorily by its means was the formation of a complex idea out of simpler parts, but the idea of a relation among facts is not accurately described as a complex idea; and, as such relations have no basis in impressions, Hume is linall driven to a confession of the absolute impossibility of explaining thlem. Such confession, however, is only reached after a vigorous effort had been made to render some account of knowledge by the experimental method. The psychological conception, then, on the basis of which Hume p.oceeds to discuss the theory of knowledge, is that of conscious experience as containing merely the succession of isolated A I impressions and their fainter copies, ideas, and as bound “SSM” together by merely natural or external l1nks of connexion, ou the principles of association among ideas. The foundations of cognition must be discovered by observation or analysis of experience so conceived. Hume way ers somewhat in his division of the yarious kinds of cognition, laymg stress now upon one now upon another of the points m which mainly they differ from one another. Nor IS It of the first importance, save with the view of criticizing his own consistency, that we should adopt any of the divisions implied ll] his exposition. For p1act1cal purposes we may regard the most important discussions in the Treatise as falling under two heads. In the first place there are certain principles of cognition which appear to rest upon and to express relations of the universal elements m conscious experience, viz. space and time. The propositions of mathematics seem to be independent of this or that special fact of experience, and to remain unchanged even when the concrete matter of experience varies. They are formal. In the second place, cognition, 1n any real sense of that term, im l1es connexion for the indidual mind between the present fact of) experience and other facts, whether past or fut11re. It appears to mvolye, therefore, some real relation among the portions of experience, on the basis of which relation judgments and inferences as to matters of fact can be shown to rest. The theoretical question is consequently that of the nature of the supposed relation, and of the certainty of judgments and inferences resting on it.

Hume's well-known distinction between relations of ideas and matters of fact corresponds fairly to th1s separation of the formal and rcal problems in the theory of cognition. although that distinction is 1n itself inadequate and not fully representative of Hume's own conclusions.

With regard, then, to the first problem, the formal element in knowledge, Hume has to consider several questions, distinct in nature and hardly discriminated by him with sufficient precision. For a complete treatment of this portion of the theory of knowledge, there require to be taken into cons1derat1on at least the following po1nts (a) the exact nature and s1gn1f1cance of the space and time relations in our experience, (b) the mode 1n which the primary data, facts or pr1nc1ples, of mathematical cogn1t1on are obtained, (c) the nature, extent and certainty of such data, in themselves and with reference to the concrete material of experience, (d) the principle of inference from the data, however obtamed. Not all of these points are discussed bv Hume w1th the same fulness, and with regard to some of them it is d1ff1cult to State his conclusions. It will be of service, however, to attempt a summary of his treatment under these several heads, -the more so as almost all expositions of his philosophy are entirely defective in the account given of this essential portion. The brief statement in the Inquzry, § iv., is of no value, and indeed is almost un1ntell1g1ble unless taken in reference tcrtjhe full discussion contained in part ii. of the Treatise. (a) The nature of space and time as elements in conscious experience is considered by Hume in relation to a special problem, that of their supposed 1nf1n1tc d1y1s1b1lity. Evidently upon his S d

I0W of conscious experience, of the world of imagination, ug? an

such infinite divisibility must be a fiction. The ultimate elements of experience mllSt be real units, capable of being represented or ima 1ned m isolation. Whence then do these units arise? or, if we put tie problem as it was necessary Hume should put it to himself, 1n what orders or classes of impressions do we find the elements of space and time? Beyond all question Hume, in endeavouring to answer this problem, is brought face to face with one

of the difficulties inherent Ill his conception of conscious experience.