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.

If we possessed a thorough knowledge of all the parts of the seed of any animal (e.g. man), we could from that alone, be reasons entirely mathematical and certain, deduce the whole conformation and figure of each of its members, and, conversely if we knew several peculiarities of this conformation, we would from those deduce the nature of its seed.

For each of us there is a set limit to our intellectual powers which we cannot pass.

I was convinced that our beliefs are based much more on custom and example than on any certain knowledge.

There is a little gland in the brain in which the soul exercises its functions in a more particular way than in the other parts.

Few look for truth; many prowl about for a reputation of profundity by arrogantly challenging whichever arguments are the best.

Omnia apud me mathematica fiunt.