of psychical phenomena on physiological conditions, and endeavors to show definite brain vibrations as the basis not only of habit, memory, and the association of ideas, but also of the higher mental operations.  In harmony with these views he adheres to determinism, and finds the motive of all endeavor:  in self-love, and its ultimate aim in happiness.  To the latter the hope of immortality is indispensable.  The link between Bonnet’s theory of the thoroughgoing dependence of the soul on the body and his orthodox convictions, is formed by his idea of an imperishable ethereal body, which enables the soul in the life to come to remember its life on earth and, after the dissolution of the present material body, to acquire a new one.  Animals as well as men share in the continuance of existence and the transition to a higher stage.

The material earnestness of these thinkers is in sharp contrast to the superficial and frivolous manner in which Helvetius (1715-71) carries out sensationalism in the sphere of ethics.  His chief work, On Mind, came out in 1758; and a year after his death, the work On Man, his Intellectual Faculties and his Education.  The search for pleasure or self-love is, as Helvetius thinks he has discovered for the first time,[1] the only motive of action; the laws of interest reign in the moral world as the laws of motion in the physical world; justice and love for our neighbors are based on utility; we seek friends in order to be amused, aided, and, in misfortune, compassionated by them; the philanthropist and the monster both seek only their own pleasure.

[Footnote 1:  In reality not only English moralists, but also some among his countrymen, had anticipated him in the position that all actions proceed from selfishness, and that virtue is merely a refined egoism.  Thus La Rochefoucauld in his Maxims (Reflexions, ou Sentences et Maximes Morales, 1665), La Bruyere (Les Characteres et les Moeurs de ce Siecle, 1687), and La Mettrie (of. pp, 251-253).]

Helvetius draws the proof for these positions from Condillac.  Recollection and judgment are sensation.  The soul is originally nothing more than the capacity for sensation; it receives the stimulus to its development from self-love, i.e., from powerful passions such as the love of fame, on the one hand, and, on the other, from hatred of ennui, which induces man to overcome the indolence natural to him and to submit himself to the irksome effort of attention—­without passion he would remain stupid.  The sum of ideas collected in him is called intellect.  All distinctions among men are acquired, and concern the intellect only, not the soul:  that which is innate—­sensibility and self-love—­is the same in all; differences arise only through external circumstances, through education.  Man is the pupil of all that environs him, of his situation and his chance experience.  The most important instrument in education is the