Rousseau a Freethinking Christian, but deeply Imbued with Religious Sentiments.
Diderot a Capricious Materialist.
D'Holbach and Helvetius Avowed Materialists.
Condillac a Philosopher of Sensations.
VOLTAIRE; ROUSSEAU.—The French philosophy of the eighteenth century, fairly feeble it must be avowed, seemed as if dominated by the English philosophy, excepting Berkeley, but especially by Locke and David Hume, more particularly Locke, who was the intellectual deity of those Frenchmen of that epoch who were interested in philosophy.
Whenever Voltaire dealt with philosophy, he was only the echo of Locke whose depths he failed to fathom, and to whom he has done some injury, for reading Locke only through Voltaire has led to the belief that Locke was superficial.
Rousseau was both the disciple and adversary of Hobbes, as often occurs, and dealt out to the public the doctrines of Hobbes in an inverted form, making the state of nature angelic instead of infernal, and putting the government of all by all in the place of government by one, invariably reaching the same point with a simple difference of form; for if Hobbes argued for despotism exercised by one over all, Rousseau argued for the despotism of all over each. In Émile, he was incontestably inspired by the ideas of Locke on education in some degree, but in my opinion less than has been asserted. On nearly all sides it has been asserted that Rousseau exercised great influence over Kant. I know that Kant felt infinite admiration for Rousseau, but of the influence of Rousseau upon Kant I have never been able to discover a trace.
DIDEROT; HELVETIUS; D'HOLBACH.—It was particularly on David Hume that Diderot depended. The difference, which is great, is that David Hume in his scepticism remained a grave, reserved man, well-bred and discreet, and was only a sceptic, whilst Diderot was violent in denial and a man of paradoxes and jests, both impertinent and cynical.
It is almost ridiculous in a summary history of philosophy to name as sub-Diderots, if one may so express it, Helvetius and D'Holbach, who were merely wits believing themselves philosophers, and who were not always wits.
CONDILLAC.—Condillac belongs to another category. He was a very serious philosopher and a vigorous thinker. An exaggerated disciple of Locke, while the latter admitted sensation and reflection as the origin of ideas, Condillac admitted only pure sensation and transformed sensation—that is to say, sensation transforming itself. The definition of man that he deduces from these principles is very celebrated and it is interesting: "The ego of each man is only the collection of the sensations that he feels and of those his memory recalls; it is the consciousness of what he is combined with the recollection of what he has been." To Condillac, the idea is a sensation which has fixed itself and which has been renewed and vivified by others; desire is a sensation which wishes to be repeated and seeks what opportunity offers for its renewal, and the will itself is only the most potent of desires. Condillac was voluntarily and systematically limited, but his system is well knit and presented in admirably clear and precise language.