What is faith? Is it to believe that which is evident? No. It is perfectly evident to my mind that there exists a necessary, eternal, supreme, and intelligent being. This is no matter of faith, but of reason.
The system of Descartes... seemed to give a plausible reason for all those phenomena; and this reason seemed more just, as it is simple and intelligible to all capacities. But in philosophy, a student ought to doubt of the things he fancies he understands too easily, as much as of those he does not understand.
Descartes constructed as noble a road of science, from the point at which he found geometry to that to which he carried it, as Newton himself did after him. ... He carried this spirit of geometry and invention into optics, which under him became a completely new art.
The atheists are for the most part imprudent and misguided scholars who reason badly who, not being able to understand the Creation, the origin of evil, and other difficulties, have recourse to the hypothesis the eternity of things and of inevitability.
You see, Mademoiselle, I have experience, I know the world. To pass the time, why don't you ask every passenger to tell you his life's story? And if there is a single one among them who has never cursed his life, who has not often told himself that he was the unhappiest of men, then you may throw me overboard, headfirst!
I have wanted to kill myself a hundred times, but somehow I am still in love with life. This ridiculous weakness is perhaps one of our more stupid melancholy propensities, for is there anything more stupid than to be eager to go on carrying a burden which one would gladly throw away, to loathe one’s very being and yet to hold it fast, to fondle the snake that devours us until it has eaten our hearts away?
A circumstance which has always appeared wonderful to me, is that such sublime discoveries should have been made by the sole assistance of a quadrant and a little arithmetic.