The first half of the book covers the same ground as the articles in 'The Philosophical Review.' The criticism of current theories of emotion has been revised, but has not been materially altered. The chapters on "The Nature of Emotion" and "The Primary Emotions" have been amended, enlarged, and largely rewritten. The second half of the book deals with the primary principles of action and with the ethical significance of results attained throughout. The discussion of the notion of Worth, which appears in the concluding chapter, embodies some of the results of an article on "Natural Selection in Ethics" which was published in 1901 in 'The Philosophical Review.'

My obligations to different writers in ethics and psychology have been acknowledged, as far as possible, in the text. I desire, however, to express my special obligations to Professor James of Harvard. In the actual preparation of this volume I have received valuable criticisms and suggestions from Mr Norman Smith of the University of Glasgow. I am also indebted to Dr Albert Lefevre of Cornell University for the assistance he has rendered in reading the proofs.

D. I.

THIS investigation is an attempt to ascertain the general principles affecting human conduct. It is undertaken in the hope that results will be attained which will throw light on current ethical problems. The present state of psychology seems to afford sufficient justification for an inquiry of this sort. The psychology of cognition has always obtained more than its relative share of attention, and in recent years the intellectualistic bias has received. support and encouragement from the spread of experimental psychology, since cognition lends itself most readily to experimental treatment. This onesided development has profoundly influenced the whole structure of the science. One evidence of its influence is the general tendency towards Presentationism. The best example of this point of view in its extreme form is Professor Münsterberg's earlier position, as stated in Die Willenshandlung. Münsterberg assumes at the outset that the only irreducible mental element is sensation, and that sensation is characterised by quality, intensity, and