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

Everything that is possible demands to exist.

It is a good thing to proceed in order and to establish propositions. This is the way to gain ground and to progress with certainty.

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

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.

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.

One cannot explain words without making incursions into the sciences themselves, as is evident from dictionaries; and, conversely, one cannot present a science without at the same time defining its terms.