Leibniz on Other Philosophers
Plato
"I find it natural that you have enjoyed some of my thoughts after having penetrated into Plato's, an author who has meant much to me and who deserves to be systematized. I believe that I can carry out the demonstrations of truths which he has merely advanced." Letter to Nicolas Remond, 10 January 1710 (GP III 605/L 654)
"Indeed, of all the ancient philosophers, Plato suits me the most in relation to metaphysics." Letter to Louis Bourguet, 22 March 1714 (GP III 568)
"I have always been most satisfied, even from my youth, with the ethics of Plato and in some way with his metaphysics as well; these two sciences demand each other's company, as do mathematics and physics. If someone were to reduce Plato to a system, he would render a great service to mankind, and it would then be clear that my own views approach his a little." Letter to Nicolas Remond, 11 February 1715 (GP III 637/L 659)
Giordano Bruno
"The author does not lack esprit, but he is not very profound." (Dutens V, 292)
Hugo Grotius
"Mr. Grotius was a very learned man and possessed a solid mind, but he was not enough of a philosopher to reason with all the necessary exactitude about subtle matters, of which he was not able to write." Letter to Thomas Burnett, 11 December 1705 (G III 304)
Ralph Cudworth
"I forgot to tell you, Sir, that at one time Lady Masham, daughter of Mr. Cudworth and a great patron of Mr. Locke, sent me her late father's Intellectual System [The True Intellectual System of the World]. In it I found much learning, but not enough reflection." Letter to Nicolas Remond, 1715 (Dutens V, 25)
Knorr von Rosenroth
As to the Kabbalists, the Kabbala Denudata of the late M. Knorrius, who was a man of great learning and one of my friends, merits being read; he wanted to reduce it to a system." Letter to Louis Bourguet, 3 January 1714 (GP III 563)