Some of the recent writers on sociology have devoted themselves particularly to the task of establishing one basal principle which may be applied to the interpretation of all social phenomena. At least half a dozen claims to the discovery of such a principle have been put forward. Prof. Ludwig Gumplowicz finds the elementary social fact to be conflict; Prof. Guillaume De Greef finds it to be contract; M. Gabriel Tarde contends that the fundamental principle of society is imitation; Prof. Emile Durkheim argues that it is "the coercion of the individual mind by modes of action, thought, and feeling external to itself." Professor Giddings criticises all these explanations of society, as either too special or too general, and undertakes to prove that "the original and elementary fact in society is the consciousness of kind." This is the determining principle to which all social phenomena are to be referred.[34] But Professor Giddings's sociological postulate has been promptly rejected by his American colleagues, Prof. Albion W. Small and Mr. Lester F. Ward. The former speaks contemptuously of the consciousness of kind as a remote metaphysical category, and declares that the whole system of sociology based on the principle is "an impossible combination of contradictions."[35] This opinion is approved by Ward, who riddles Giddings's book with criticism, and complains of the author's inability to handle principles correctly.[36] [Footnote 34: See Giddings. Principles of Sociology, chap. i.] [Footnote 35: In American Journal of Sociology, September, 1896.] [Footnote 36: In Annals of the American Academy, July, 1896.] It is hardly necessary to penetrate further into this debate over first principles. The most exhaustive examination of the writings of the leaders in sociological thought would fail to discover any fundamental unity of opinion. The so-called principles of the science are multiform. They represent merely the unsupported conclusions of individual thinkers. If we except the barest commonplaces, no truths have been established; no scientific laws have been agreed upon. The content of the science of sociology, as expounded in treatises bearing this name, varies with the particular bias of the writer. In fine, there are systems of sociology galore, but there is hardly a sociology.