CONCEPTS AND METHODS OF SOCIOLOGY 165
only takes account of individuality as well as of mutuality, but that also it carries our interpretation of solidarity farther back than the theories of impression and of imitation, % since both impression and imitation must be accounted for in ultimate psychological analysis as phenomena of reciprocal, or inter- stimulation and response. Indeed, the very language that Tarde uses throughout his exposition tacitly assumes as much. Example is stimulus, the imitative act is response to stimulus. The impression that the crowd makes upon an individual is stimulus, and the submission, obedience, or conformity of the individual is response to stimulus. Moreover, the formation of the crowd itself has to be accounted for, and it will be found that, in many cases, the formation of a crowd is nothing more nor less than the simultaneous like-response of many individuals to some inciting event, circumstance, or suggestion. In short, impression, imitation, and conformity are specific modes, but not by any means the primary or simplest modes, of stimulation and response; and some of the most important phenomena of con- certed action can be explained only as springing directly from primary like-responses, before either imitation or impression has entered into the process.
This conception meets one further scientific test. It offers a simple and consistent view of the relation between social life and the material universe. It assumes that the original causes of society lie in the material environment, which may be regarded as an infinitely differentiated group of stimuli of like-response, and therefore of collective action; while the products of past social life, constituting the historical tradition, become in their turn secondary stimuli, or secondary causes, in the social process.
A mere momentary like-response by any number of indi- viduals is the beginning of social phenomena, but it does not con- stitute a society. Before society can exist there must be con- tinuous exposure to like influences, and repeated reaction upon them. When this happens, the individuals thus persistently act- ing in like ways become themselves mentally and practically alike. But likeness is not identity. The degrees of resemblance or of difference in the manner of response to common stimuli manifest
