In this book, which was to exert a large influence in England, Helvetius sought, among other things, to show that the science of morals is equivalent to the science of legislation, and that in a well-organised society all men are capable of rising to the highest point of mental development.  Intellectual and moral inequalities between man and man arise entirely from differences in education and social circumstances.  Genius itself is not a gift of nature; the man of genius is a product of circumstances—­social, not physical, for Helvetius rejects the influence of climate.  It follows that if you change education and social institutions you can change the character of men.

The error of Helvetius in ignoring the irremovable physical differences between individuals, the varieties of cerebral organisation, was at once pointed out by Diderot.  This error, however, was not essential to the general theory of the immeasurable power of social institutions over human character, and other thinkers did not fall into it.  All alike, indeed, were blind to the factor of heredity.  But the theory in its collective application contains a truth which nineteenth century critics, biassed by their studies in heredity, have been prone to overlook.  The social inheritance of ideas and emotions to which the individual is submitted from infancy is more important than the tendencies physically transmitted from parent to child.  The power of education and government in moulding the members of a society has recently been illustrated on a large scale in the psychological transformation of the German people in the life of a generation.

It followed from the theory expounded by Helvetius that there is no impassable barrier between the advanced and the stationary or retrograde races of the earth. [Footnote:  The most informing discussion of the relations between the Advanced and Backward races is Bryce’s Romanes Lecture (1902).] “True morality,” Baron d’Holbach wrote, “should be the same for all the inhabitants of the globe.  The savage man and the civilised; the white man, the red man, the black man; Indian and European, Chinaman and Frenchman, Negro and Lapp have the same nature.  The differences between them are only modifications of the common nature produced by climate, government, education, opinions, and the various causes which operate on them.  Men differ only in the ideas they form of happiness and the means which they have imagined to obtain it.”  Here again the eighteenth century theorists held a view which can no longer be dismissed as absurd.  Some are coming round to the opinion that enormous differences in capacity which seem fundamental are a result of the differences in social inheritance, and that these again are due to a long sequence of historical circumstances; and consequently that there is no people in the world doomed by nature to perpetual inferiority or irrevocably disqualified by race from playing a useful part in the future of civilisation.