NEW BOOKS. 117 dents' and not with the 'essence' of judgment. Activity, therefore, being excluded, the question is : Does introspection reveal, besides the facts of association, some other psychological fact which may be taken as the differentia of judgment ? The author professes to have found such a fact in what he calls ' the negative relation of ideas,' i.e., the most primitive and simple form of the experience of error. The author illustrates the meaning of ' negative relation of ideas ' by the following example : I see a distant figure and take it to be a woman. On coming nearer, however, I perceive that the figure is pushing a cart and thereby I recognise it to be a man. Here we have the partial displacement of one idea (woman) by another (man) mediated by a third (pushing a cart). There need be, in primitive levels of mental life, no explicit judgment in all this, but we certainly have all the germs of judgment. For we have the correction of one idea by another, and of this correction we are aware as a distinct experience, which remains in memory and leaves an ' idea ' of itself behind. And this new idea, like any other idea, is capable of entering into all kinds of associative relations to others, and in particular it comes to accompany all combinations of ideas produced by the psycho- logical mechanism. In other words, we no longer simply accept these combinations, but, owing to the accompanying idea of former errors, we now learn to consider the possibility of error, and therefore the possi- bility of withholding our assent, unless we find reasons for giving it. In this idea of former error, which thus enters as a modifying factor into the ordinary associative process, we have the beginnings of ' critical thinking '. The remainder of the book is mainly concerned with the further developments of ' negative relation ' in the higher and more complex levels of Thought. Here the author adopts Taine's theory of substitution to show, that the idea of possible error, leading to suspension of judgment and setting the machinery of association in motion to bring up reasons for or against, need not be explicitly present in consciousness, but that its place may be taken by a ' symbol,' such as a word, a gesture, or even a mere feeling, whilst the idea itself remains below the threshold of consciousness. It is clear that the author's theories all rest on his peculiar but inter- esting view as to the limits of introspective self-observation, and as they will have to be judged on that basis, it may be worth while to characterise it a little more fully. It is a kind of Phenomenalism, and therefore con- fesses itself unable to deal with the realities of psychic life : ' we do not deny the existence of will, still less the existence of intellectual feelings. On the contrary we regard the latter as the most real elements of our psychic life. But we cannot discover them by introspection and ob- servation. Introspection reveals to us only sensations and ideas ' (p. 130), and, as we may add from other passages, the ' changes ' happening to those ideas. Because of this restriction to ideas the author charac- terises his Psychology as ' Intellectual srn ' (p. 54). The point in which he passes most clearly beyond Associationism is in not merely formu- lating ' laws ' of Association, but in assuming that the changes among ideas, and their mutual relations to each other, are themselves expe- rienced in such a way as to leave new ideas behind, which afterwards through the associations into which they enter themselves, modify the original stream of thought. This enables him to trace back all the higher developments of thought to that comparatively simple break with ordinary association which he calls the ' negative relation of ideas '. E. F. ALFRKD HOERNL&
