Arthur Eddington Physics Quotations

It is impossible to trap modern physics into predicting anything with perfect determinism because it deals with probabilities from the outset.

In the most modern theories of physics probability seems to have replaced aether as "the nominative of the verb 'to undulate'."

To the pure geometer the radius of curvature is an incidental characteristic - like the grin of the Cheshire cat. To the physicist it is an indispensable characteristic. It would be going too far to say that to the physicist the cat is merely incidental to the grin. Physics is concerned with interrelatedness such as the interrelatedness of cats and grins. In this case the "cat without a grin" and the "grin without a cat" are equally set aside as purely mathematical phantasies.

So far as physics is concerned, time's arrow is a property of entropy alone.

In Einstein's theory of relativity the observer is a man who sets out in quest of truth armed with a measuring-rod. In quantum theory he sets out with a sieve.