Section 33. The suggestions, touching the attitude of the psychologist toward the mind, contained in the preface to Professor William James's "Psychology" are very interesting and instructive.
CHAPTER IX, sections 35-36. For a strong argument in favor of interactionism see James's "Psychology," Chapter V. I wish the student would, in reading it, bear in mind what is said in my chapter on "The Atomic Self," above referred to. The subject should be approached with an open mind, and one should suspend judgment until both sides have been heard from.
Section 37. Descartes held that the lower animals are automata and that their actions are not indicative of consciousness; he regarded their bodies as machines lacking the soul in the "little pineal gland." Professor Huxley revived the doctrine of animal automatism and extended it so as to include man. He regarded consciousness as a "collateral product" of the working of the body, related to it somewhat as is the steam-whistle of a locomotive engine to the working of the machine. He made it an effect, but not a cause, of motions. See "System of Metaphysics," Chapter XVIII, "The Automaton Theory: its Genesis."
We owe the doctrine of parallelism, in its original form, to Spinoza. It was elaborated by W. K. Clifford, and to him the modern interest in the subject is largely due. The whole subject is discussed at length in my "System of Metaphysics," Chapters XIX-XXI. The titles are: "The Automaton Theory: Parallelism," "What is Parallelism?" and "The Man and the Candlestick." Clifford's doctrine is presented in a new form in Professor Strong's recent brilliant work, "Why the Mind has a Body" N.Y., 1903.
Section 38. See "System of Metaphysics," Chapter XXIV, "The Time and Place of Sensations and Ideas."
CHAPTER X, sections 40-42. See "System of Metaphysics," Chapters XXVII and XXVIII, "The Existence of Other Minds," and "The Distribution of Minds."
Writers seem to be divided into three camps on this question of other minds.
(1) I have treated our knowledge of other minds as due to an inference. This is the position usually taken.
(2) We have seen that Huxley and Clifford cast doubts upon the validity of the inference, but, nevertheless, made it. Professor Strong, in the work mentioned in the notes to the previous chapter, maintains that it is not an inference, and that we do not directly perceive other minds, but that we are assured of their existence just the same. He makes our knowledge an "intuition" in the old-fashioned sense of the word, a something to be accepted but not to be accounted for.
(3) Writers who have been influenced more or less by the Neo-Kantian or Neo-Hegelian doctrine are apt to speak as though we had the same direct evidence of the existence of other minds that we have of the existence of our own. I have never seen a systematic and detailed exposition of this doctrine. It appears rather in the form of hints dropped in passing. A number of such are to be found in Taylor's "Elements of Metaphysics."