Page:Mind (Old Series) Volume 12.djvu/598

 G. T. LADD, ELEMENTS OF PHYSIOLOGICAL PSYCHOLOGY. 585 then, to be the predominating function of the right Jiemi- as motion is of the left ". The next two chapters treat of " The Quality of Sensations," and here real progress has been made during the past forty years, both in experimental research and in psychological analysis. Prof. Ladd says (p. 306) : " As respects developed experience the simple sensation is a necessary fiction of psychophysical science. Consciousness is scarcely more able directly to analyse a presentation of sense into those factors out of which it origi- nated than it is to analyse a drop of water into its component oxygen and hydrogen gases." But he thinks " scientific analysis " can do what " introspec- tion " cannot. In so far as analysis of the sense-stimulus is meant by scientific analysis we are on ground foreign to psycho- logy. Physical and physiological research may lead us to look for complexity in consciousness where we had not expected it, as in the sound of the human voice, but the fact that the physical stimulus associated with the sensation of white light is more com- plex than that associated with blue does not make the sensation any the less simple. How far the introspective analysis of con- sciousness will be able to advance cannot be foretold ; we may however be sure that we shall never reach simple and isolated elements out of which consciousness can be constructed. Such a point of view has been the source of much evil to psychology. It either leads, as in Hume, to the practical denial of the unity of consciousness, or, as in Prof. Ladd's book, to the assumption of a mind with a mysterious power of creating unity of consciousness out of sensation-atoms. It is as though Prof. Ladd should analyse abc into a + b + c, and then say that as a + b + c does not equal a x b x c, it must be multiplied by x ; or as though he should divide the human body into head, limbs, &c., and say that as these parts when taken separately do not make up the body, they can- not when taken together. It seems necessary to lay stress on this fallacy, as it unfortunately plays a large part in the book. Prof. Ladd's account of the psychophysical researches into the quality of sensations is, in general, concise and accurate. He begins with smell and taste, thus reversing the usual order of treatment. I cannot agree with Prof. Ladd in thinking that, while it is impossible to classify smells, it is easy to classify tastes. No combination of sweet, sour, bitter and salt will give vanilla or chocolate, nor can the taste of lemon and sugar be analysed into sour + sweet. Sensations of sound are well, but considering the importance of the researches of Helmholtz, Stumpf and others somewhat briefly treated. Mr. Gurney's valuable book on The Power of Sound is not referred to. Impor- tant researches from the laboratory at Leipsic are probably too re- cent for mention : indeed some of these are only now in press, although the experiments were made so long as three years ago. 38