Thus God alone is the primary Unity, or original simple substance, from which all monads, created and derived, are produced.

Logic is the foundation of the certainty of all the knowledge we acquire.

Justice is a charity in accordance with wisdom.

Taking mathematics from the beginning of the world to the time when Newton lived, what he had done was much the better half.

Nature does not make leaps.

The present is big with the future, the future might be read in the past, the distant is expressed in the near.

Every present state of a simple substance is the natural consequence of its preceding state, in such a way that its present is big with its future.

Nothing is necessitated whose opposite is possible.

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

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

There are also two kinds of truths: truth of reasoning and truths of fact.

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

We live in the best of all possible worlds

It is necessary to believe that the mixture of evil has produced the greatest possible good: otherwise the evil would not have been permitted.

To love is to take delight in happiness of another, or, what amounts to the same thing, it is to account another's happiness as one's own.

A great doctor kills more people than a great general.

To love is to find pleasure in the happiness of others.

What is is what must be.

He who understands Archimedes and Apollonius will admire less the achievements of the foremost men of later times.