Perfect numbers like perfect men are very rare.

If I found any new truths in the sciences, I can say that they follow from, or depend on, five or six principal problems which I succeeded in solving and which I regard as so many battles where the fortunes of war were on my side.

It is best not to go on for great quest for truth , it will only make you miserable

These long chains of perfectly simple and easy reasonings by means of which geometers are accustomed to carry out their most difficult demonstrations had led me to fancy that everything that can fall under human knowledge forms a similar sequence; and that so long as we avoid accepting as true what is not so, and always preserve the right order of deduction of one thing from another, there can be nothing too remote to be reached in the end, or to well hidden to be discovered.

I concluded that I might take as a general rule the principle that all things which we very clearly and obviously conceive are true: only observing, however, that there is some difficulty in rightly determining the objects which we distinctly conceive.

Now therefore, that my mind is free from all cares, and that I have obtained for myself assured leisure in peaceful solitude, I shall apply myself seriously and freely to the general destruction of all my former opinions.

A person has two passions for love and abhorrence. A big disposition to excessiveness has just a love, because it is more ardent and stronger.