thereby. Such a characteristic must be produced as its passport into the kingdom of science, and the author believes he has found what is necessary in the "consciousness of kind." That the conception is deemed of vital importance is proved by the following statements. Consciousness of kind is "the cause of the distinctively social phenomena of communities" (p. vi). The sub-title of the book is "an Analysis of the Phenomena of Association and of Social Organization," and the preface states that "association and social organization I have attempted to explain as consequences of the consciousness of kind" (p. v). "Human nature is the preëminently social nature. Its primary factor is a consciousness of kind" (p. 225). "Subjectively, progress is the expansion of the consciousness of kind" (p. 359).
The idea expressed in the foregoing quotations is apparently a recent development of the author's thought. In his Theory of Sociology, published less than two years earlier and sketching the theoretical positions elaborated in the present work, there is no mention of the consciousness of kind. This may account for a degree of incoherence in the present volume. For example, the definition of sociology finally reached is: "An interpretation of social phenomena in terms of psychical activity, organic adjustment, natural selection, and the conservation of energy" (p. 419). From other passages one would have anticipated that the consciousness of kind would be included among the keys to the explanation of social phenomena. This definition, however, is repeated from the Theory of Sociology (p. 73), and doubtless was formulated prior to the theory of the consciousness of kind. The same change of view may explain the different estimates put upon M. Tarde's theory of imitation as the primary social fact. In 1895 our author wrote: "Of all these writers it is Tarde who has perceived the true and ultimate nature of social facts" (Article 'Sociology' in Johnson's Cyclopaedia); in the present work he says: "Neither Tarde nor Durkheim has perfectly discriminated the social fact" (p. 16), for that is the consciousness of kind.
What, then, is this nucleus, about which "all other motives organize themselves in the evolution of social choice, social volition, or social policy" (p. 19)? It is "a state of consciousness in which any being, whether low or high in the scale of life, recognizes another conscious being as of like kind with itself" (p. 17). The author's statement of this position in an earlier paper may throw light upon his definition. "Mere physical contact is association, if and only if accompanied by a consciousness, on the part of each of the creatures implicated, that the creatures with which it comes in contact are like
