“Indeed every monad must be different from every other. For there are never in nature two beings, which are precisely alike, and in which it is not possible to find some difference which is internal, or based on some intrinsic quality.”

Indeed in general I hold that there is nothing truer than happiness, and nothing happier and sweeter than truth.

I also take it as granted that every created thing, and consequently the created monad also, is subject to change, and indeed that this change is continual in each one.

A great doctor kills more people than a great general.

The past is pregnant with the present.

There is no way in which a simple substance could begin in the course of nature, since it cannot be formed by means of compounding.

What is what must be.

In whatever manner God created the world, it would always have been regular and in a certain general order. God, however, has chosen the most perfect, that is to say, the one which is at the same time the simplest in hypothesis and the richest in phenomena.

The knowledge which we have acquired ought not to resemble a great shop without order, and without an inventory; we ought to know what we possess, and be able to make it serve us in need.

Nature does not make leaps.

It is unworthy of excellent men to lose hours like slaves in the labor of calculation which could be relegated to anyone else if machines were used.

I am so in favor of the actual infinite that instead of admitting that Nature abhors it, as is commonly said, I hold that Nature makes frequent use of it everywhere, in order to show more effectively the perfections of its Author.

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.

Men act like brutes in so far as the sequences of their perceptions arise through the principle of memory only, like those empirical physicians who have mere practice without theory.

There is nothing waste, nothing sterile, nothing dead in the universe; no chaos, no confusions, save in appearance.

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

All things in God are spontaneous.