He who loves practice without theory is like the sailor who boards ship without a rudder and compass and never read more

He who loves practice without theory is like the sailor who boards ship without a rudder and compass and never knows where he may cast.

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.

The theory seems to be that as long as a man is a failure he is one of God's children, read more

The theory seems to be that as long as a man is a failure he is one of God's children, but that as soon as he succeeds he is taken over by the Devil.

It is the theory that decides what can be observed

It is the theory that decides what can be observed

A purpose, an intention, a design, strikes everywhere the careless, the most stupid thinker

A purpose, an intention, a design, strikes everywhere the careless, the most stupid thinker

How empty is theory in the presence of fact

How empty is theory in the presence of fact

An ounce of action is worth a ton of theory.

An ounce of action is worth a ton of theory.

You have to know you can first. How comes later.

You have to know you can first. How comes later.

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

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