Science should leave off making pronouncements: the river of knowledge has too often turned back on itself.

Put three grains of sand inside a vast cathedral, and the cathedral will be more closely packed with sand than space is with stars.

...to many it is not knowledge but the quest for knowledge that gives greater interest to thought-to travel hopefully is better than to arrive.

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

...nature seems very conversant with the rules of pure mathematics, as our own mathematicians have formulated them in their studies, out of their own inner consciousness and without drawing to any appreciable extent on their experience of the outer world.

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

Sciences usually advances by a succession of small steps, through a fog in which even the most keen-sighted explorer can seldom see more than a few paces ahead. Occasionally the fog lifts, an eminence is gained, and a wider stretch of territory can be surveyed-sometimes with startling results. A whole science may then seem to undergo a kaleidoscopic rearrangement, fragments of knowledge sometimes being found to fit together in a hitherto unsuspected manner. Sometimes the shock of readjustment may spread to other sciences; sometimes it may divert the whole current of human thought.