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.

The word reality frightens me.

Philosophically, the notion of a beginning of the present order of Nature is repugnant to me ... I should like to find a genuine loophole.

If your theory is found to be against the second law of thermodynamics I give you no hope; there is nothing for it but to collapse in deepest humiliation.

It is reasonable to hope that in the not too distant future we shall be competent to understand so simple a thing as a star.

The pursuit of truth in science transcends national boundaries. It takes us beyond hatred and anger and fear. It is the best of us.

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.