For since it is impossible for a created monad to have a physical influence on the inner nature of another, this is the only way in which one can be dependent on another.

I hold that it is only when we can prove everything we assert that we understand perfectly the thing under consideration.

The art of discovering the causes of phenomena, or true hypotheses, is like the art of deciphering, in which an ingenious conjecture often greatly shortens the road.

Imaginary numbers are a fine and wonderful refuge of the divine spirit almost an amphibian between being and non-being.

Philosophy consists mostly of kicking up a lot of dust and then complaining that you can't see anything.

Now, as there is an infinity of possible universes in the Ideas of God, and as only one of them can exist, there must be a sufficient reason for God's choice, which determines him toward one rather than another. And this reason can be found only in the fitness, or the degrees of perfection, that these worlds contain, since each possible thing has the right to claim existence in proportion to the perfection it involves.

Nothing is more important than to see the sources of invention which are, in my opinion more interesting than the inventions themselves.