Makch 10, 1916] 



SCIENCE 



353 



tical iiiiitarisiii, are all set down as dualistic. 

 His own solution of the problem is that " the 

 psychical and the material are not two dis- 

 tinct entities, but denote two different kinds 

 of regularity — parallel regularity and causal 

 regularity" (I., 150). 



The following chapter treats of conscious- 

 ness. In common usage the term conscious- 

 ness has three essentially different meanings : 

 it denotes (1) a substantial unitary "self" 

 or " soul," (2) a specific process or function in 

 the psychical sphere, (3) a specific property of 

 the psychical. l^Tone of these uses appears 

 satisfactory. According to the author, as al- 

 ready stated, " the psychical denotes not a 

 specific entity, but merely the Qignomene in 

 so far as the latter includes parallel components 

 in accordance with the parallel laws " (I., 

 206). The notion of imconscious mental proc- 

 esses is not only self contradictory, but it is 

 quite superfluous from his viewpoint. On the 

 other hand, the " reduction constituents " of 

 the datum are unconscious, and in this sense 

 the term " unconscious " has a valid meaning. 

 The first volume concludes with a discussion 

 of the relation of psychology to logic, esthetics 

 and ethics. 



In the second part Professor Ziehen devel- 

 ops the autochthonous foundations of psychol- 

 ogy. He recognizes both the objective and the 

 subjective methods of research, including 

 under the latter self-observation and observa- 

 tion of others. But according to his view 

 " introspection " is not a special process : it is 

 rather an associative mode of succession of 

 mental processes. The introspection of a sen- 

 sation is a representation corresponding to 

 that sensation, and the representation of a 

 representation is merely a repetition of the 

 latter. Both induction and deduction are ap- 

 propriate methods of investigation in psychol- 

 ogy proper, whereas in psychophysics and 

 psychophysiology only induction is admissible. 

 Under induction he includes the genetic and 

 experimental methods, but considers the ques- 

 tionnaire method a caricature of the true ex- 

 perimental procedure. 



The aim of psychology may be either gen- 

 eral or individual. Under general psychology 



he includes anthropological psychology, ani- 

 mal psychology, and the special fields of gen- 

 eral mass psychology and the psychology of 

 types. Under individual psychology he notes 

 one special field: special mass psychology. 



The remainder of the work is devoted to an 

 examination of the psychical subject-matter. 

 The two universal characteristics of the 

 psychical are temporality and variability. At 

 the outset the author had divided the primary 

 datum into sensory and representative Gigno- 

 mene. Whether or not this classification is 

 exhaustive can only be determined by analysis 

 of every sort of experience. Taking up the 

 various types of experience which psychology 

 has recognized as fundamental, he proceeds to 

 show that they are all reducible to sensations 

 and representations, or transformations of 

 representations, or their simultaneous and. 

 successive combinations. The author's anal- 

 ysis of judgment, feeling and volition is espe- 

 cially thorough and interesting. Judgment is 

 resolved into a particular sort of representa- 

 tion. The hedonic experiences, instead of 

 forming a third distinct group of data, are 

 found to be merely specific properties of sen- 

 sations and representations. Volitions are 

 reducible to certain combinations of sensory 

 and representative data — namely, those in 

 which a strong pleasure-tone is united to the 

 representation of a " purpose." 



Professor Ziehen's book wiU interest the 

 psychologist of a speculative turn of mind. 

 His attempt to resolve the data of experience 

 into causal and parallel components is a defi- 

 nite contribution to the mind-body problem. 

 To the present reviewer, though he differs 

 with the author in standpoint, the theory ap- 

 pears to be developed logically from plausible 

 premises. The obscurity of language in the 

 early part of the analysis may be due to the 

 difficulty of defining fundamental ideas such 

 as reduction-component, etc., or it may be the 

 result of attempting to treat non-mathematical 

 terms by means of algebraic symbols and opera- 

 tions. Whatever the reason, the analysis here 

 is exceedingly difficult for even the psychol- 

 ogist to comprehend. It is doubtful whether 

 the physicist and physiologist, to whom these 



