256 CRITICAL NOTICES : such was not attempted, yet such a comparison, difficult as it would be in practice, is alone relevant to our author's theory. Many other points, which call for discussion, have been un- noticed, as not bearing directly on the argument of the work. There are throughout many subtle and suggestive observations on quantity, measurement, and relations. The author's contention, if it perhaps simplifies the question, especially in the interpretation of Weber's Law, with somewhat excessive optimism, is based on very close and careful reasoning, and offers, on essentials, very few vulnerable points. B. EUSSELL. Psychologic als Erfahrungswissenschaft. Von HANS COKNELIUS. Leipzig : Druck und Verlag von B. G. Teubner. London : Williams & Norgate, 1897. Pp. xv., 445. THE title of this work is somewhat deceptive. It is concerned more with theory of knowledge than with psychology ; indeed, it would seem that the author does not recognise the distinction between the two. He assumes that an account of the way in which knowledge grows in the individual mind is at the same time an explanation of its nature and validity. The result is not good ; both his psychology and theory of knowledge suffer. He has written a valuable and interesting book, as a man of his ability could not fail to do. But the confusion between two- distinct lines of inquiry is a great drawback. The theory of knowledge advocated by Prof. Cornelius is clear and simple. He begins by recognising what he calls the " symbolic function of memory-images " as an ultimate and inexplicable fact. The present image represents for the con- sciousness of the subject the previous experience of which it is a reproduction. It is impossible to say how it comes to play this- part. Its representative function must simply be accepted as a final inexplicability (pp. 20-28). On the other hand, he makes ar interesting attempt to trace all other symbolic functions of presen- tation to that which is involved in memory. I do not think that this attempt is successful (pp. 57-62). But this part of his worl is suggestive. Given a mental image which is symbolic of ar experience not actually present at the moment, the question of the truth or falsehood of the symbolism may arise. The test of trutt is verification by the actual experience of the cognitive subject. If it is possible for the subject to actualise his symbols by obtain- ing the experiences symbolised in the order and manner in whicl they are symbolised, his mental representations are true. The conception of objective existence is identical with the conceptior of the possible realisation in terms of individual experience of what is ideally represented by the cognitive subject. The author applies this theory to explain the nature of oui
