“We may say, that not only the soul (the mirror of an indestructible universe) is indestructible, but also the animal itself is, although its mechanism is frequently destroyed in parts.”

Music is a secret and unconscious mathematical problem of the soul.

Although the whole of this life were said to be nothing but a dream and the physical world nothing but a phantasm, I should call this dream or phantasm real enough, if, using reason well, we were never deceived by it.

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 don’t say that bodies like flint, which are commonly called inanimate, have perceptions and appetition; rather they have something of that sort in them, as worms are in cheese.

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.

There is nothing without reason.

If you have a clear idea of a soul, you will have a clear idea of a form; for it is of the same genus, though a different species.

Reality cannot be found except in One single source, because of the interconnection of all things with one another.

In symbols one observes an advantage in discovery which is greatest when they express the exact nature of a thing briefly and, as it were, picture it; then indeed the labor of thought is wonderfully diminished.

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

The present is great with the future.

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.