What we makes of the world must be largely dependent on the sense-organs that we happen to possess. How the world must have changed since the man came to rely on his eyes rather than his nose.

The mathematics is not there till we put it there.

An ocean traveler has even more vividly the impression that the ocean is made of waves than that it is made of water.

The electron, as it leaves the atom, crystallises out of Schrodinger's mist like a genie emerging from his bottle.

The helium which we handle must have been put together at some time and some place. We do not argue with the critic who urges that the stars are not hot enough for this process; we tell him to go and find a hotter place.

Our model of Nature should not be like a building-a handsome structure for the populace to admire, until in the course of time some one takes away a corner stone and the edifice comes toppling down. It should be like an engine with movable parts. We need not fix the position of any one lever; that is to be adjusted from time to time as the latest observations indicate. The aim of the theorist is to know the train of wheels which the lever sets in motion-that binding of the parts which is the soul of the engine.

Man is slightly nearer to the atom than to the star. ... From his central position man can survey the grandest works of Nature with the astronomer, or the minutest works with the physicist. ... [K]nowledge of the stars leads through the atom; and important knowledge of the atom has been reached through the stars.