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

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

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.

The words 'Here you can find perfect peace' can be written only over the gates of a cemetery.

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

To love is to place happiness in the heart of another.

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

Why is there anything at all rather than nothing whatsoever?

Nihil est sine ratione. There is nothing without a reason.

Make me the the master of education, and I will undertake to change the world.

Music is a hidden arithmetic exercise of the soul, which does not know that it is counting.

The world is not a machine. Everything in it is force, life, thought.