The deepest definition of youth is life as yet untouched by tragedy.

Do not teach too many subjects and what you teach, teach thoroughly.

The deepest definition of youth is life as yet untouched by tragedy.

To see what is general in what is particular, and what is permanent in what is transitory, is the aim of scientific thought.

The science of pure mathematics, in its modern developments, may claim to be the most original creation of the human spirit.

The way in which the persecution of Galileo has been remembered is a tribute to the quiet commencement of the most intimate change in outlook which the human race had yet encountered. Since a babe was born in a manger, it may be doubted whether so great a thing has happened with so little stir

Education with inert ideas is not only useless; it is above all things harmful.