“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.”

Either there are no corporeal substances, and bodies are merely phenomena which are true or consistent with each other, such as a rainbow or a perfectly coherent dream, or there is in all corporeal substances something analogous to the soul.

Now this connection or adaption of all created things with each, and of each with all the rest, means that each simple substance has relations which express all the others, and that consequently it is a perpetual living mirror of the universe.

The most perfect society is that whose purpose is the universal and supreme happiness.

He who hasn’t tasted bitter things hasn’t earned sweet things.

There is a world of created beings – living things, animals, entelechies, and souls – in the least part of matter…. Thus there is nothing waste, nothing sterile, nothing dead in the universe; no chaos, no confusions, save in appearance.

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

But in simple substances the influence of one monad over another is ideal only.

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.