If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations - then so much the worse for Maxwell's equations. If it is found to be contradicted by observation - well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can 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 has put into nature. We have found a strange foot-print on the shores of the unknown. We have devised profound theories, one after another, to account for its origin. At last, we have succeeded in reconstructing the creature that made the foot-print. And Lo! it is our own.

Schrödinger's wave-mechanics is not a physical theory, but a dodge - and a very good dodge too.

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?"

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

It is one thing for the human mind to extract from the phenomena of nature the laws which it has itself put into them; it may be a far harder thing to extract laws over which it has no control. It is even possible that laws which have not their origin in the mind may be irrational, and we can never succeed in formulating them.

It is also a good rule not to put overmuch confidence in the observational results that are put forward until they are confirmed by theory.