SOURCE: “Philosophy in France in 1919,” in The Philosophical Review, Vol. XXIX, No. 173, September, 1920, pp. 575-82.

Thilly examines Trotter's definition of the herd mentality and the role of biological psychology in the successful future of society.

[In Instincts of the Herd in Peace and War,] the first edition of which appeared in 1915, Mr. Trotter aims to show that psychology, especially when studied in relation to “other branches of biology,” is capable of becoming a guide in the actual affairs of life, and even of enabling us to foretell in a practical and useful way “some of the course of human behavior.” It is his ambition to lay the foundations for a true science of politics which will be of direct service to the statesman. The first two essays, discussing the psychology of the herd instinct, were first published in the Sociological Review in 1908 and 1909; these are followed by “Speculations...