[174]. Compare the following striking passage from Avenarius, Menschliche Weltbegriff, p. 75: “Let an individual M denote a definite whole of ‘perceived things’ (trunk, arms and hands, legs and feet, speech, movements, etc.) and of ‘presented thoughts’ as I, ... then when M says ‘I have a brain,’ this means that a brain belongs as part to the whole of perceived things and presented thoughts denoted as I. And when M says ‘I have thoughts,’ this means that the thoughts themselves belong as a part to the whole of perceived things and presented thoughts denoted as I. But though thorough analysis of the denotation of I thus leads to the result that we have a brain and thought, it never leads to the result that the brain has the thoughts. The thought is, no doubt, a thought of ‘my Ego,’ but not a thought of ‘my brain’ any more than my brain is the brain of ‘my thought.’ I.e. the brain is no habitation, seat, generator, instrument or organ, no support or substratum of thought. Thought is no indweller or commander, no other half or side, and also no product, indeed not even a physiological function or so much as a state of the brain.”
[175]. As elsewhere in this work, I am using the terms “mind” and “soul” as virtually interchangeable names for the object studied by the psychologist. So far as there is any definite distinction of meaning between the terms as currently used by English writers, “soul” seems to carry with it more of the implication of substantiality and relative independence than “mind.” It might not be amiss to adopt the term “soul” as a name for the finite subject of experience as he is for himself in actual social life, and to confine the name “mind” to the construction which symbolises this subject for psychological purposes. But the popular antithesis between soul and body is perhaps too strongly rooted to admit of this suggestion. In earlier passages, e.g., Book II. chap. 2, § 6, I have used the term “spirit” in the sense here suggested for “soul.”
[176]. So, in dealing with astronomical problems, we are free to adopt either the Copernican or the Ptolemaic scheme, whichever happens to be the more convenient for our special purpose. The superior truth of the Copernican system seems to mean no more than that the range of its utility is the wider of the two. I may observe that I do not here employ the term “utility” in the narrowly practical sense of those philosophers who, e.g., condemn all speculation about the “Absolute” on the ground of inutility. Whatever satisfies any human aspiration is for me, so far, “useful.” It follows that there is, for me, no such thing as the “useless knowledge” which “Pragmatism” denounces. Thus, if a man’s peace of mind depends upon speculation about the “Absolute”—on the habits of angels, or any other topic you like (and this is a matter in which every man must in the end decide for himself)—Pragmatism would appear to be false to its own principle in forbidding him to speculate.
[177]. The assumption is not always made, however. Professor Münsterberg, who classes himself as a supporter of Parallelism, holds on metaphysical grounds that all causal connection must be between physical states. Hence he denies that psychical states can be causally connected with one another, except indirectly through the causal relations of their physical correlates. His doctrine is thus hardly to be distinguished from Epiphenomenalism, except in terminology, though he avoids the consequence of practical Fatalism by his insistence upon the purely artificial nature of both the physical and the psychical series. (His reason for refusing to admit causal relation between psychical states is that causal connection can only be established between universals, whereas every psychical state is unique. Does not this argument imply a confusion between the actual experience and its psychological symbol?)
[178]. Most supporters of Parallelism, it may be noted, stultify their own case, so far as it rests on this special contention, by admitting the causal determination of psychical states by one another, though, as psychical states are essentially qualitative, the reduction of causation to quantitative identity is particularly inadmissible here. Professor Münsterberg is quite consistent, therefore, in denying psychical causality and reducing Parallelism to Epiphenomenalism.
[179]. The reader who has followed the argument of our Third Book will not need to be reminded that the world of purely mechanical processes is simply an ideal construction based on postulates which we make for their practical convenience, and in no sense a direct transcript of the world of actual experience.
[180]. The “neutral Monism” to which the doctrine of rigid Parallelism logically leads, when put forward as more than a working hypothesis, will, one may hope, in England at least, fail to survive the exposure of its illogicalities in the second volume of Professor Ward’s Naturalism and Agnosticism.
[181]. This case includes, as will be apparent on a little reflection, not only the initiation of new motor reactions upon a sensation or percept, but also that of sensation itself as a qualitatively novel reaction upon physiological stimulation, and thus includes both the processes in which supporters of Interaction have always recognised the causal interconnection of the physical and the psychical.
[182]. It is with great pleasure that I note the coincidence of my own view on the impossibility of reconciling Parallelism with the recognition of the psychological importance of “meaning” with that of Mr. Gibson (essay on “The Problem of Freedom,” in Personal Idealism, p. 150 ff.). Professor Münsterberg’s[Münsterberg’s] declaration, that the consciousness investigated by Psychology “knows nothing by its knowledge and wills nothing by its will,” seems to me a confession of the bankruptcy of Parallelism as a basal psychological hypothesis. Still more so his elaborate and brilliant demonstration that the “brain” with which my “mind” may be regarded as “parallel” is not the brain as studied and charted by the anatomist, i.e. not the brain as a physical object at all. See Psychologie, i. 415-428.
[183]. See his essay on “Error” in Personal Idealism.