The distinguishing character of human psychology is that to the three great factors, organism, external medium, and heredity; it adds a fourth, namely, the relation to a social medium, with its product, the general mind.... While the mental functions are products of the individual organism, the product, mind, is more than an individual product. Like its great instrument language, it is at once individual and social. Each man speaks in virtue of the functions of vocal expression, but also in virtue of the social need of communication. The words spoken are not his creation, yet he, too, must appropriate them by what may be called a creative process before he can understand them. What his tribe speaks he repeats; but he does not simply echo their words, he rethinks them. In the same way he adopts their experiences when he assimilates them to his own.... Further, the experiences come and go; they correct, enlarge, and destroy one another, leaving behind them a certain residual store, which condensed in intuitions and formulated in principles, direct and modify all future experiences.... Men living in groups co-operate like the organs in an organism. Their actions have a common impulse to a common end. Their desires and opinions bear the common stamp of an impersonal direction. Much of their life is common to all. The roads, market-places and temples are for each and all. Customs arise and are formulated in laws, the restraint of all.... Each generation is born in this social medium, and has to adapt itself to the established forms.... A nation, a tribe, a sect is the medium of the individual mind, as a sea, a river, or a pond, is the medium of a fish.[2] [1] It will ease my feelings if I am permitted to here make a protest against the shameless way in which this suggestive writer has been pillaged by others without the slightest acknowledgement. They have found him, as Lamb said of some other writers, "damned good to steal from." His series of volumes, _Problems of Life and Mind_, have been borrowed from wholesale without the slightest thanks or recognition.