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 have to know you can first. How comes later.

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

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

An ounce of action is worth a ton of theory.

An ounce of action is worth a ton of 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.

[Do not] put too much confidence in experimental results until they have been confirmed by theory.

[Do not] put too much confidence in experimental results until they have been confirmed by theory.

There can be no theory of any account unless it corroborate with the theory of the earth.

There can be no theory of any account unless it corroborate with the theory of the earth.

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.

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.