But these did not, of course, agree among themselves.

But these did not, of course, agree among themselves. Helvétius perhaps stands at one extreme, Diderot at another. Claude-Adrien Helvétius (1751-71) caused such scandal with his psychological materialism that he was forced to retire from the French royal service. Reasoning, as well as perception, according to Helvétius, consists solely in a chain of sensations. Of sensations, some are painful, some pleasant, some neutral. Everyone desires his own pleasure and nothing else.

Everything else which men appear to desire they desire only as a means to their pleasure. Some men are pained by the pain of others and pleased by the pleasure of others. They…