Page:Mind (Old Series) Volume 11.djvu/417

 416 CRITICAL NOTICES : We next pass to a study of images generally, and here Mr. Galton's studies do M. Binet yeoman's service. He is thereby enabled to give the gradations from impression to after-image, from after-image to memory-image, and from this to generic image. But M. Binet is not content with merely repeating previous observers : he has much of interest to add from his own special work, and this part of the book is filled with interesting details which recall the days of Abercrombie and Carpenter and what we may style anecdotic psychology. Most of these anecdotes have been published before by M. Binet, but he now brings them to bear with considerable skill on the theory of perception. He claims that this has been considerably advanced by the study of hallucination, and this is of course a favourite thesis just now with Prof. Eibot and his followers. Yet it would be difficult to point to any specific point in which our knowledge of the normal pro- cesses in perception has been advanced by a study of its abnormal conditions. Of course these latter serve as excellent illustrations, and enable us to show the elements of a complex in separation or with differing intensity. But it is doubtful whether we should recognise that these were part of the same complex unless we had observed the fact under normal conditions. The appeal is rather from the abnormal to the normal than vice versa. As a matter of fact in the case before us, the use of mental pathology seems to have confused rather than aided the study of the normal processes. What strikes one in hallucinations is the intolerable deal of imagination that clusters about the slightest scintilla of sensation. A few inequalities in a piece of cardboard are sufficient to form & point il'n^jini for a likeness of the hypno- tised patient who projects it upon the cardboaixl at the suggestion of the experimenter. But, small as is the modicum of sensation needed, there is always some : the more uniform the cardboard, the less chance of the portrait being projected (p. 57). Again, in the experiments of M. Binet the experimenter were hypnotised, or, in other words, their power of voluntary attention was dormant and that of involuntary attention was only capable of being ecu trally initiated by suggestion. But it is easy to see that, if only by a mere process of natural selection, an animal would learn to concentrate attention on the external sensation which came to it provided with local signs, and thus to subordinate the " images " which enable it to bring its former experience to bear on the presentation of the moment. In illusions and hallucinations the subordination is the other way. Thus, by looking at the subject from the point of view suggested by his hypnotic experiments, M. Binet is tempted to neglect the essential difference between the objectified sensation and the concomitant " images " and to leave out of account the action of attention. It is only by this means that he is able to assume the identification of perception and reasoning which forms the main thesis of his book. This identification he symbolises in a very suggestive way.