384 CRITICAL NOTICES: nature, we find Mr. Stout, in his opening chapter in volume i., discussing, with agreeable brevity, the general scope and methods of our science. The psychologist (p. 4) has a right to take account of any uniformities that can be observed or inferred in the course of mental events themselves ; and is not forced to proceed to physiological or other extra-conscious explanations, except in so far as (p. 20) the "existence and inter-connexion of conscious states is most distinctly and intelligibly formulated by the intro- duction of physiological links and co-operating conditions ". The psychologist may, however, also legitimately make use of the hypothesis of the so-called "psychical dispositions," either with or without a reference to their physiological aspect. In this way it becomes clear that the psychologist, as such, is primarily interested in detecting, if possible, uniformities with/in the field of consciousness. Where these uniformities fail him, he proceeds to fill up the gaps by appealing to " psychical dispositions " whose nature is so far more or less hypothetical, and then, on occasion, to the physiological bases of these dispositions. In order to dis- cover his facts, the psychologist appeals to "introspection,"' to "retrospection," and to communication with other minds. Of these three methods, Mr. Stout considers (p. 14) that the third is a "derivative method which presupposes the other two, although they do not presuppose it". He continues by observing that "there is no such a thing as direct observation of other minds; all that is immediately perceptible consists of sensible signs and tokens of inward events ; and these sensible signs and tokens are interpretable only through knowledge attained by introspection or retrospection ". Physiological knowledge in its present states of development is (p. 26 sqg.) of secondary importance for the psychologist ; and (p. 34) "it is clear that psychology must do the main body of its own work on its own lines " ; and (p. 35) "it is idle to require psychology to wait for the progress of physiology". When one has such a conception as this of the means by which the psychologist is to discover the laws of mental processes, we naturally inquire what types of laws one believes oneself to have discovered by those methods which, beginning with introspection and retrospection, regard all other psychological methods as second- ary to these. We shall probably not be mistaken in asserting that Mr. Stout finds these uniformities especially exemplified, in so far as they are accessible to direct introspection, in the early chapters of his second book, especially in the chapter on " The Concept of Mental Activity," and in the chapter on " The Process of Attention ". Numerous, and decidedly valuable, generalisations as to the laws of mental life appear in volume ii., and fill a considerable portion of our author's text. But one is especially concerned to observe that precisely where these laws are most definitely stated, they, for the most part, cannot be stated as the results of mere introspection. When, for instance, our attention
