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. CHAPTER VI KANT Kant Reconstructed all Philosophy by Supporting it on Morality. KNOWLEDGE.--Kant, born at Koenigsberg in 1724, was professor there all his life and died there in 1804. Nothing happened to him except the possession of genius. He had commenced with the theological philosophy in use in his country, that of Wolf, which on broad lines was that of Leibnitz. But he early read David Hume, and the train of thought of the sceptical Scotsman at least gave him the idea of submitting all philosophic ideas to a severe and close criticism.