Gottfried von Leibniz

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.

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

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.

Music is the pleasure the human soul experiences from counting without being aware that it is counting.

Nothing is more important than to see the sources of invention which are, in my opinion more interesting than the inventions themselves.

The art of discovering the causes of phenomena, or true hypothesis, is like the art of decyphering, in which an ingenious conjecture greatly shortens the road.

The imaginary number is a fine and wonderful recourse of the divine spirit, almost an amphibian between being and not being.

The soul is the mirror of an indestructible universe. The Monadology.

Philosopher and mathematician Gottfried Leibniz speculated on the possibility of "intermediate species" over a century before the publication of Darwin's theory: "All advances by degrees in Nature, and nothing by leaps, and this law as applied to each, is part of my doctrine of Continuity. Although there may exist in some other world species intermediate between Man and the Apes, Nature has thought it best to remove them from us, in order to establish our superiority beyond question. I speak of intermediate species, and by no means limit myself to those leading to Man. I strongly approve of the research for analogies; plants, insects, and Comparative Anatomy will increase these analogies, especially when we are able to take advantage of the microscope more than at present."

[about him:] It is rare to find learned men who are clean, do not stink and have a sense of humour.