In theory there is no difference between theory and practice. In practice there is.

In theory there is no difference between theory and practice. In practice there is.

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.

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.

It is the theory that decides what can be observed

It is the theory that decides what can be observed

There is a theory which states that if ever for any reason anyone discovers what exactly the Universe is for read more

There is a theory which states that if ever for any reason anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.

If the facts don't fit the theory, change the facts.

If the facts don't fit the theory, change the facts.

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

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

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.

Let us work without theorizing, 'Tis the only way to make life endurable.

Let us work without theorizing, 'Tis the only way to make life endurable.