An electron is no more (and no less) hypothetical than a star. Nowadays we count electrons one by one in a Geiger counter, as we count the stars one by one on a photographic plate.

You cannot disturb the tiniest petal of a flower without the troubling of a distant star.

Unless the structure of the nucleus has a surprise in store for us, the conclusion seems plain — there is nothing in the whole system of laws of physics that cannot be deduced unambiguously from epistemological considerations.

If I let my fingers wander idly over the keys of a typewriter it might happen that my screed made an intelligible sentence. If an army of monkeys were strumming on typewriters they might write all the books in the British Museum. The chance of their doing so is decidedly more favourable than the chance of the molecules returning to one half of the vessel.

Electrical force is defined as something which causes motion of electrical charge; an electrical charge is something which exerts electric force.

Observation and theory get on best when they are mixed together, both helping one another in the pursuit of truth. It is a good rule not to put overmuch confidence in a theory until it has been confirmed by observation. I hope I shall not shock the experimental physicists too much if I add that it is also a good rule not to put overmuch confidence in the observational results that are put forward until they have been confirmed by theory.

Don't believe the results of experiments until they're confirmed by theory.