In attempting to discover the law of human progress, the first step must be to determine the essential nature of those differences which we describe as differences in civilization.

That the current philosophy, which attributes social progress to changes wrought in the nature of man, does not accord with historical facts, we have already seen. And we may also see, if we consider them, that the differences between communities in different stages of civilization cannot be ascribed to innate differences in the individuals who compose these communities. That there are natural differences is true, and that there is such a thing as hereditary transmission of peculiarities is undoubtedly true; but the great differences between men in different states of society cannot be explained in this way. The influence of heredity, which it is now the fashion to rate so highly, is as nothing compared with the influences which mould the man after he comes into the world. What is more ingrained in habit than language, which becomes not merely an automatic trick of the muscles, but the medium of thought? What persists longer, or will quicker show nationality? Yet we are not born with a predisposition to any language. Our mother tongue is only our mother tongue because we learned it in infancy. Although his ancestors have thought and spoken in one language for countless generations, a child who hears from the first nothing else, will learn with equal facility any other tongue.