Helvetius has exhibited the moral consequences of the sensualistic standpoint. While theoretical sensualism affirms that all our knowledge is determined by sensation, practical sensualism adds to this the analogous proposition that all our volition springs from the same source, and is regulated by the sensuous desire. Helvetius adopted it as the principle of morals to satisfy this sensuous desire.

Helvetius was born at Paris in 1715. Gaining a position in his twenty-third year as farmer-general, he found himself early in the possession of a rich income, but after a few years he found this office so vexatious that he abandoned it. The study of Locke decided his philosophic direction. Helvetius wrote his famed work, de l’Esprit, after he had given up his office and withdrawn himself in seclusion. It appeared in 1758, and attracted a great attention at home and abroad, though it drew upon him a violent persecution, especially from the clergy. It was fortunate for him that the persecution satisfied itself with suppressing his book. The repose in which he spent his later years was interrupted only by two journeys which he made to Germany and England. He died in 1771. His personal character was wholly estimable, full of kindness and generosity. Especially in his place as farmer-general he showed himself benevolent towards the poor, and resolute against the encroachments of his subalterns. The style of his writings is easy and elegant.

Self-love or interest, says Helvetius, is the lever of all our mental activities. Even that activity which is purely intellectual, our instinct towards knowledge, our forming of ideas, rests upon this. Since now all self-love refers essentially only to bodily pleasure, it follows that every mental occurrence within us has its peculiar source only in the striving after this pleasure; but in saying this, we have only affirmed where the principle of all morality is to be sought. It is an absurdity to require a man to do the good simply for its own sake. This is just as impracticable as that he should do the evil simply for the sake of the evil. Hence if morality would not be wholly fruitless, it must return to its empirical basis, and venture to adopt the true principle of all acting, viz., sensuous pleasure and pain, or, in other words, selfishness as an actual moral principle. Hence, as a correct legislation is that which secures obedience to its laws through reward and punishment, i. e. through selfishness, so will a correct system of morals be that which derives the duties of men from self-love, which shows that that which is forbidden is something which is followed by disagreeable consequences. A system of ethics which does not involve the self-interest of men, or which wars against this, necessarily remains fruitless.