On Chapter XII, I find no comment necessary. As to Chapter XIII, I recommend to the reader a reading or re-reading of the fascinating pages in which James treats of instinct in his _Psychology_. And let him look up the same subject in McDougall's _Social Psychology_. At the same time, I enter a note of warning against reading even such good writers uncritically. There is no little dispute in this field. Dr. H. R. Marshall's volume _Mind and Conduct_ gives an unusually thoughtful account of instinct (N. Y., 1919). Comment on Chapter XIV is not imperatively necessary. But I must speak with detail of Chapter XV, for the best of men quarrel when they come upon this ground: Sec 49. The psychologist takes into his mouth no word more ambiguous than "feeling." It may be used to indicate any mental content whatever--John Stuart Mill could speak of consciousness as composed of a string of feelings. Herbert Spencer divided conscious processes into "feelings" and "relations between feelings." James obliterates the distinction, and finds it possible to speak of "a feeling of _and_, a feeling of _if_, a feeling of _but_," etc. (_Psychology_ I, p. 154, ff.). Some writers do not distinguish between emotions and feelings. Thus, Darwin, in his _Descent of Man_, calls pleasure and pain "emotions." Marshall (_op. cit._, chapter ii) makes emotions, and even intuitions, "instinct-feelings." Dewey, in his _Ethics_ (p. 251), appears to treat emotions as synonymous with feelings. Gardiner, in his interesting and careful study, _Affective Psychology in Ancient Writers after Aristotle_ (_Psychological Review_. May, 1919), treats of "what are popularly called the feelings, including emotions." On the other hand, in ethical writings the word, "feelings," very often means no more than pleasure and pain. Thus, _Seth_ (_A Study of Ethical Principles_, p. 63), makes feelings synonymous with pleasure and pain. Muirhead (_Elements of Ethics_, p. 46), says, "by feeling is meant simply pleasure and pain"; and to have "interest" in, he defines as to have pleasure in (p. 46). This narrowing of the meaning of the word on the part of ethical writers is, perhaps, natural. The hedonistic moralists made pleasure and pain the only ultimate reasonable stimulants to action. Many moralists opposed them (see, later, Chapters XXIV and XXV). So pleasure and pain became "the feelings," _par excellence_. Both Dewey and Alexander sometimes speak as if, by the word "feeling," we meant no more than pleasure and pain. So does Kant. The modern psychologist sometimes distinguishes pleasure and pain from "agreeableness" and "disagreeableness." Marshall, a high authority on pleasure and pain, refuses to draw the distinction (_op. cit._, Part III. chapter vi). But he also refuses to call pleasure and pain sensations, regarding them as "qualifications of our sensations," like intensity, duration, and the like.