It cannot be said how extraordinarily distracted I am. I dig things out of the archives, I inspect old papers, I search for unknown manuscripts. From these I try to throw light on the history of Brunswick. I send and receive a great number of letters. I truly have so many new results in mathematics, so many philosophical ideas, so many other scholarly observations which I would not want to lose, that I often hesitate, wavering between tasks, and feel almost like that line from Ovid: Inopem me copia fecit .... Nevertheless, all these labors of mine, if you exclude the historical, are almost clandestine, for you know that at the Court something far different is sought and expected.” Letter to Placcius, 5 September 1695 (Dutens VI.1, 59-60)
I read books not to criticize them but to profit from them. The result is that I find good everywhere, though not equally.” Letter to Morell, 10/20 December 1696 (A I.13, 398)
He who knows me only through what I have published does not know me.” Letter to Placcius, 1697 (Dutens VI.1, 65)
Provided that something of importance is achieved, I am indifferent whether it is done in Germany or France, for I seek the good of mankind. I am neither a phil-Hellene nor a philo-Roman but a phil-anthropos.” Letter to Gilles des Billettes, 11/21 October 1697 (G VII 456/L 475)
The true metaphysics, or philosophy, if you will, appears to me no less important than geometry, especially if there is also a way of introducing into it demonstrations, which until now have been entirely excluded from it, along with the calculus that will be necessary in order to give them all the entry they need. However, it is necessary to prepare readers with exoteric writings. The journals have served me well until now.” Letter to Fontanelle, 1704 (Foucher de Careil, 234)
It is true that my Theodicy does not suffice to present my system as a whole. But if it is joined with what I have published in various journals, those of Leipzig, Paris, and those of M. Bayle and M. Basnage, it will not fall short of doing so, at least for the principles.” Letter to Remond, July 1714 (GP III 618/L 656-7)
I scorn nothing readily (with the exception of the divinatory arts, which are nothing but sheer trompery through and through).” (GP III 620)
Giordano Bruno
The author does not lack esprit, but he is not very profound.” (Dutens
V, 292)
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)
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)
Monads are entirely indivisible.... However, solitary monads do not exist. They are monads, not monks.” Letter to G. Wagner, 3 March 1698 (Grua 395)
The monad, of which we shall speak here is nothing but a simple substance that enters into composites; simple, that is, without parts.” Monadology, sec. 1.
Monads have no windows, through which anything could enter or leave. Accidents cannot be separated from substances or go about outside of them, as the sensible species of the Scholastics used to do. Thus neither substance nor accident can enter a monad from without.” Monadology, sec. 7.
Moreover, it must be confessed that perception and that which depends on it are inexplicable in mechanical terms, that is, in terms of figures and motions. And supposing there were a machine, so constructed as to think, feel, and have perception, one could imagine it increased in size, while keeping the same proportions, so that one could go into it as into a mill. In that case, we should, on examining its interior, find only parts that work upon one another, and never anything by which to explain a perception. Thus, perception must be sought in a simple substance, and not in a composite or machine. Further, nothing but this (namely, perceptions and their changes) can be found in a simple substance. It is in this alone also that all the internal actions of simple substances can consist.” Monadology, sec. 17.
“I cannot think about my dynamics, or about other philosophical and mathematical matters, until I have rid myself of my present historical labor.” Letter to Bourguet, 20 April 1716 (Dutens VI, 220)