There are only two kinds of certain knowledge: Awareness of our own existence and the truths of mathematics.

A philosopher is a fool who torments himself while he is alive, to be talked of after he is dead.

The true system of the World has been recognized, developed and perfected...Everything has been discussed and analysed, or at least mentioned.

To someone who could grasp the Universe from a unified standpoint the entire creation would appear as a unique truth and necessity.

Thus metaphysics and mathematics are, among all the sciences that belong to reason, those in which imagination has the greatest role. I beg pardon of those delicate spirits who are detractors of mathematics for saying this . . . . The imagination in a mathematician who creates makes no less difference than in a poet who invents. . . . Of all the great men of antiquity, Archimedes may be the one who most deserves to be placed beside Homer.

Music that paints nothing is only noise.

In England it was enough that Newton was the greatest mathematican of his century; in France he would have been expected to be agreeable too.