I never once made a discovery ... I speak without exaggeration that I have constructed three thousand different theories in read more

I never once made a discovery ... I speak without exaggeration that I have constructed three thousand different theories in connection with the electric light ... Yet in only two cases did my experiments prove the truth of my theory.

Conjecture as to things useful, is good; but conjecture as to what it would be useless to know, is very read more

Conjecture as to things useful, is good; but conjecture as to what it would be useless to know, is very idle.

You cannot run a business, or anything else, on a theory.

You cannot run a business, or anything else, on a theory.

It is the theory that decides what can be observed

It is the theory that decides what can be observed

An ounce of action is worth a ton of theory.

An ounce of action is worth a ton of theory.

Whenever a theory appears to you as the only possible one, take this as a sign that you have neither read more

Whenever a theory appears to you as the only possible one, take this as a sign that you have neither understood the theory nor the problem which it was intended to solve

Relativity applies to physics, not ethics

Relativity applies to physics, not ethics

In scientific work, those who refuse to go beyond fact rarely get as far as fact.

In scientific work, those who refuse to go beyond fact rarely get as far as fact.

A young boy is a theory, an old man is a fact.

A young boy is a theory, an old man is a fact.