and the assertion that animal actions can be completely expressed and accounted for in terms of nervous matter and motion.  The laws of the mind, he maintained, are not to be deduced from physiological processes, but with them must be joined the psychical processes of the individual and the social man.  He separates man by an impassable barrier from the lower animals, this gulf between them being due to human society and to the social acquisition of language.  In the social factor he finds an important element of psychology, and one that must always come in to overturn any mechanical theories of mental activity.

It has been very truly said, that Lewes must be credited with the doctrine of the dependence of the human mind on the social medium.  Others had hit upon this idea, and it had been very well developed by Spencer and Comte; but Lewes gave it a wider and profounder interpretation than any other.  One of his critics says that Lewes “has the sort of claim to have originated this theory that Bacon has to be considered the discoverer of the inductive method.”  He not only held with Spencer and other evolutionists, that the human mind is the product of experience in contact with the outer world, that experience transmitted by heredity and built up into mental processes and conclusions; but he maintained that the social medium is a much greater and more important factor.  The past makes the present; the social life develops the individual.  Our language, our thought, as individuals, are the product of the collective life of the race.  “We are to seek in the social organism for all the main conditions of the higher functions, and in the social medium of beliefs, opinions, institutions, &c., for the atmosphere breathed by the intellect.  Man is no longer to be considered simply as an assemblage of organs, but also as an organ in a collective organism.  From the former he derives his sensations, judgments, primary impulses; from the latter, his conceptions, theories and virtues.  This is very clear when we learn how the intellect draws both its inspiration and its instrument from the social needs.  All the materials of intellect are images and symbols, all its processes are operations on images and symbols.  Language—­which is wholly a social product for a social need—­is the chief vehicle of symbolical operation, and the only means by which abstraction is affected....  Language is the creator and sustainer of that ideal world in which the noblest part of human activity finds a theatre, the world of thought and spiritual insight, of knowledge and duty, loftily elevated above that of sense and appetite.  Into this ideal world man absorbs the universe as in a transfiguration.  It is here that he shapes the programme of his existence; and to that programme he makes the real world conform.  It is here he forms his highest rules of conduct.  It is here he plants his hopes and joys.  It is here he finds his dignity and power.  The ideal world becomes to him the supreme reality.”