We may note some significant points in this development, although, indeed, the whole course of modern sociology is one single illustration of what has just been said. Discussions of the problem in what the differentia of society consists, no longer deal with organic or economic conceptions, but with such ideas as the “Consciousness of kind,” [1] the “Mind of a Crowd,” [2] “Imitation” and “Invention,” [3] similarities and differences in the social consciousness, [4] “Social logic” and society considered as a syllogism, [5] and the imitative and {44} inventive person. [6] The work of M. Tarde in particular is typical of the whole movement, and his phrases have largely been adopted whether in agreement or in controversy. For him the one fact coextensive with the social character is “Imitation”--the means by which ideas and practices spread throughout groups and masses of intelligent beings. For the characteristic of knowable phenomena, in his view, is Repetition, and Imitation is the means and vehicle of Repetition in social matters. Here, however, we have accounted only for generalisation, and differentiation needs a separate origin. This will be supplied by the idea of “Invention;” Invention and Imitation, therefore, are the general form of all social process, the matter on the other hand being analysable as Belief and Desire. Every institution is a belief, [7] every activity is a want or desire. In the _Logique Sociale_ these conceptions of the general medium and process of social life are pushed home into the actual formative operation of the social mind and will. Society, we are told, may be compared not indeed to an organism, but rather to a brain; it is a cooperative mind, a syllogism, in which the principles held by one part are modified and applied by another. M. Tarde’s extreme illustrative hypothesis corresponds strangely with one thrown out by Mr. Sidgwick. Mr. Sidgwick [8] has simplified an ethical question by supposing only a single sentient conscious being in the universe; for M. {45} Tarde there is, we might say, no single being at all; the typical social man is a hypnotical creature, a somnambulist acting under suggestions from others, though he does not know it, and is under the illusion that he is himself. [9] Nothing could be of higher interest than to see the necessities of social science thus working themselves out, on slippery and unfamiliar ground, by the sheer force of facts and experience. That a science of man must be a science of mind seems no longer disputable. [1] Giddings, p. 17. [2] Le Bon, _Psychologie des Foules_. [3] Tarde, _Les Lois de l’Imitation_. [4] Durkheim, _La Division du Travail Social_. [5] Tarde, _La Logique Sociale_. [6] Baldwin, _Social and Ethical Interpretations in Mental Development_. [7] Perhaps this expression originates with Fustel de Coulanges in _La Cité Antique_. [8] _Methods of Ethics_, p. 374. [9] _Les Lois de l’Imitation_, p. 83.