It is worth noting that the notation facilitates discovery. This, in a most wonderful way, reduces the mind’s labour.
I hold that it is only when we can prove everything we assert that we understand perfectly the thing under consideration.
Nothing is more important than to see the sources of invention which are, in my opinion more interesting than the inventions themselves.
He who understands Archimedes and Apollonius will admire less the achievements of the foremost men of later times.
I have said more than once, that I hold space to be something purely relative, as time; an order of coexistences, as time is an order of successions.
Make me 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.
It is unworthy of excellent men to lose hours like slaves in the labor of calculation which could be relegated to anyone else if machines were used.
It is necessary to believe that the mixture of evil has produced the greatest possible good: otherwise the evil would not have been permitted.
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.
Nothing is accomplished all at once, and it is one of my great maxims, and one of the most completely verified, that Nature makes no leaps: a maxim which I have called the law of continuity.
The knowledge which we have acquired ought not to resemble a great shop without order, and without an inventory; we ought to know what we possess, and be able to make it serve us in need.
In whatever manner God created the world, it would always have been regular and in a certain general order. God, however, has chosen the most perfect, that is to say, the one which is at the same time the simplest in hypothesis and the richest in phenomena.
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.
The present is big with the future, the future might be read in the past, the distant is expressed in the near.
The larger the mass of collected things, the less will be their usefulness. Therefore, one should not only strive to assemble new goods from everywhere, but one must endeavor to put in the right order those that one already possesses.
The greatness of a life can only be estimated by the multitude of its actions. We should not count the years, it is our actions which constitute our life.
Reality cannot be found except in One single source, because of the interconnection of all things with one another.
I hold that the mark of a genuine idea is that its possibility can be proved, either a priori by conceiving its cause or reason, or a posteriori when experience teaches us that it is in fact in nature.
Thus God alone is the primary Unity, or original simple substance, from which all monads, created and derived, are produced.