"the boundary line of the mental is certainly vague. It is better not to be pedantic, but to let the science be as vague as its subject, and include such phenomena [instinctive and reflex acts of self-preservation] if by so doing we can throw any light on the main business in hand." He recognizes that at a certain stage in every science vagueness best consists with fertility, and quotes in illustration the Spencerian formula that life consists in "the adjustment of inner to outer relations," which he says has done much real service in psychology though it is "vagueness incarnate." He further says that "because it takes into account the fact that minds inhabit environments which act on them and on which they react; because, in short, it takes mind in the midst of all its concrete relations, it is immensely more fertile than the old-fashioned rational psychology which treated the soul as a detached existent, sufficient unto itself, and assumed to consider only its nature and properties. I shall, therefore, feel free to make any sallies into zoology or into pure nerve-physiology which may seem instructive for our purposes." The whole book, we are told, will be more or less a proof of the proposition that the brain is the one immediate bodily condition of the mental operations.
Accordingly, Chapter II treats through *78 pages of the Functions of the Brain, and Chapter III, of over 20 pages, considers the General Conditions of Brain Activity. These two chapters embody the latest assured results of experiment and observation, along with much comment and elucidation, and are very interesting and instructive. In Chapter IV the subject of Habit is dealt with in a most practical and impressive manner. The author supports his statements by liberal quotations from Dr. Carpenter's Mental Physiology. He closes with six or seven pages upon the Ethical Implications of the Law of Habit, addressed chiefly to the young, and bearing on the formation of character. Chapter V, on the Automatic Theory, and Chapter VI, on Mind-stuff, are lively, controversial, theoretical, all-sided, and strikingly display both the author's gifts of expression and peculiarities of method. Beginners are warned against several chapters in the book as too metaphysical, the one on Mind-stuff among them. If the trusting neophyte could read this chapter understanding, it is hard to imagine the state of mind produced in him by the concluding paragraph, wherein all the points that have just been so conclusively refuted are affirmed to be, in the present state of our knowledge, the only ground of a scientific psychology. This backing and filling seem very odd in a text-book; but the author evidently can not help it. His aptitudes and tendencies are too strong to be resisted. And perhaps this non-committal, bantering, disputatious way of presenting all sides of the subject is the best possible one for the author's purpose as a teacher.
Chapter VII, on The Methods and Snares of Psychology, and Chapter VIII, on The Relations of Mind to Other Things, are also too difficult for beginners. They treat of the "outer world of objects and relations to which the brain states correspond."
In Chapter IX, on The Stream of Thought, the author enters upon the exposition of mind from within, or subjective psychology. Instead of adopting the synthetic method, and beginning, as is usual, with sensations, he begins with the process of thinking, which is treated analytically. He rejects the idea that because sensations are the simplest things they should be taken up first, and affirms that "the only thing which Psychology has a right to postulate at the outset is the fact of thinking itself, and that must first be taken up and analyzed." In this chapter he treats the subject of consciousness in a general way, and in Chapter X he discusses The Consciousness of Self. More than half of this long chapter of 110 pages is devoted to Pure Self, and treats of the Spiritualist Theory, the Associationist Theory, and the Transcendentalist Theory. He winds up the section upon The Soul Theory with the following words: "My final conclusion, then, about the substantial soul is that it explains nothing and guarantees nothing. Its successive thoughts are the only intelligible and verifiable things about it, and definitely to ascertain the correlations of these with brain-processes is as much as Psychology can empirically do."
One section of this chapter treats of The Mutations of Self, both normal and abnormal. The abnormal alterations are classed as