In this model, the sun is a very tiny speck of dust indeed-a speck less than a three-thousandth of an inch in diameter ... Think of the sun as something less than a speck of dust in a vast city, of the earth as less than a millionth part of such a speck of dust, and we have perhaps as vivid a picture as the mind can really grasp of the relation of our home in space to the rest of the universe.

The universe can best be pictured as consisting of pure thought, the thought of what for want of a better word we must describe as a mathematical thinker.

We may as well cut out group theory. That is a subject that will never be of any use in physics.

We have already considered with disfavour the possibility of the universe having been planned by a biologist or an engineer; from the intrinsic evidence of his creation, the Great Architect of the Universe now begins to appear as a pure mathematician.

All discussion of the ultimate nature of things must necessarily be barren unless we have some extraneous standards against which to compare them.

To travel hopefully is better than to arrive.

Humanity is at the very beginning of its existence-a new-born babe, with all the unexplored potentialities of babyhood; and until the last few moments its interest has been centred, absolutely and exclusively, on its cradle and feeding bottle.