Asked in 1919 whether it was true that only three people in the world understood the theory of general relativity, [Eddington] allegedly replied: "Who's the third?"

For the truth of the conclusions of physical science, observation is the supreme Court of Appeal.

Let us suppose that an ichthyologist is exploring the life of the ocean. He casts a net into the water and brings up a fishy assortment. Surveying his catch, he proceeds in the usual manner of a scientist to systematise what it reveals. He arrives at two generalisations: No sea-creature is less than two inches long. (2) All sea-creatures have gills. These are both true of his catch, and he assumes tentatively that they will remain true however often he repeats it.

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.

Probably the simplest hypothesis... is that there may be a slow process of annihilation of matter.

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.

We have found that where science has progressed the farthest, the mind has but regained from nature that which the mind put into nature.