106 CEITICAL NOTICES: Under this head fall four stages of correlation : (1) that of uncon- scious readjustment; (2) that of concrete experience and the practical judgment; (3) that of conceptual thinking and will; and (4) that of rational system. In common with Prof. Wundt and Dr. Stout among psychologists, and with such students of animal life as Dr. Thorndike and Mr. Kinnaman, the author reaches the conclusion (to which we believe both Komanes and St. George Mivart, notwithstanding wide divergence of expression, would have subscribed) that "the highest animals have as much capacity for dealing with the practical exigencies of their surround- ings as can be attained by an intelligence limited in its scope to the concrete and the practical ". No doubt there may be some, perhaps much, difference of opinion as to what is psychologically involved in this limitation to the concrete and the practical as dis- tinguished from the abstract and the intellectual. But quite apart from any discussion as to the psychological status of the higher animals the difference between what Dr Stout calls the perceptual and the conceptual planes of mental development is so well marked and so important as to justify their being placed in separate categories. We should therefore advocate three, instead of two, main divisions : I. The instinctive ; II. The intel- ligent or perceptual ; and III. the rational, intellectual or concep- tual. Of these the second would be subdivided by Mr. Hobhouse into (a) the stage of unconscious readjustment and (6) that of concrete experience and the practical judgment. Whether uncon- scious readjustment is a satisfactory designation for the modifica- tion of response to stimulus as a consequence of the pleasure or pain immediately resulting, is questionable ; but the implication is that there is no consciousness of the purpose or end of the modification. The chick that avoids cinnabar caterpillars as the result of experience, Dahl's spider which ceased to spring upon flies soaked in turpentine, and Mobius's pike of the sore nose, afford simple examples of the genesis of elementary experience through the subconscious correlation of sensory data. But how difficult it is to describe such rudimentary cases of the devel- opment of a conscious situation without using phrases which overstep the limits of legitimate inference. Mobius's pike, after dashing itself for three months against a glass partition in the attempt to get at some minnows, became, we are told, "at last so persuaded of the danger of attacking them that, when the partition was removed, it left them quite unmolested ". The transition from this stage to the next rests on the growth of experience in clearness and comprehensiveness. " In the primitive experience, the feeling modifies the sensation which it follows. Let the consciousness be extended so that sensation and feeling may be apprehended together while yet remaining distinct, and the content sensation-giving-place-to-feeling comes into being. This is the germ of the higher stage." " Psychologically, the new departure which has taken place in this stage is that the related
