Art attracts us only by what it reveals of our most secret self.

Civilization advances by extending the number of important operations which we can perform without thinking about them. Operations of thought are cavalry charges in a battle - they are limited in number, they require fresh horses, and must only be made at decisive moments.

By relieving the brain of all unnecessary work, a good notation sets it free to concentrate on more advanced problems, and in effect increases the mental power of the race.

It takes an extraordinary intelligence to contemplate the obvious.

Civilization advances by extending the number of important operations which we can perform without thinking of them.

It is natural to think that an abstract science cannot be of much importance in affairs of human life, because it has omitted from its consideration everything of real interest.

Algebra is the intellectual instrument which has been created for rendering clear the quantitative aspects of the world.