VIII. DISCUSSIONS. PERCEPTION OF CHANGE AND DURATION SOME ADDITIONAL NOTES. THE following short notes, based upon certain considerations put forth by Dr. Stout in the January number of MIND, may, perhaps, be not altogether out of place. Dr. Stout there refers to three classes of experiences temporal perception, comparison, and the apprehension and recognition of ' form-qualities '. The present paper aims at drawing certain general distinctions ; and in so far as it deals mainly with comparison, it somewhat belies its title. Further, no attempt is made to give a scientific account of the mental processes at the bottom of these experiences ; nothing is undertaken beyond the preliminary task of ascertaining what is present in consciousness when we apprehend succession, compare, etc. It remains an open question whether the conscious or appar- ent factors are a true report of the real process. From the purely introspective method pursued there follows a possibly offensive predominance of the first personal pronoun. This seems to be unavoidable, but it must be understood from that very predomi- nance that the value to be attached to distinctions drawn below is purely temporary. The final verdict must rest with those who have the opportunity to observe themselves under the accurate and repeated conditions of experiment. Hence, too, no figures are given ; and as the papers containing the figures of various experimenters are so well known, it is unnecessary to give precise references. 1. Temporal perception. (a) The view of Duration that Schu- mann takes the trouble to overthrow can scarcely be considered serious psychology, for it commits the long-branded mistake of substituting a mathematical moment for the empirical or psychical present, (b) With regard to succession and change, it seems quite plain that when presentation B follows presentation A at a mode- rate interval, no memory-image of A need be present when we apprehend A to enable us to experience change. It may be present, but its presence is not essential. Nor is it evident that the a priori argument to the contrary would have cogency, for the simple perception is not a consciousness of change from A to B, but a mere ' change-consciousness,' as Dr. Stout well terms it.