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.

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

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

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.

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

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

Relativity applies to physics, not ethics

Relativity applies to physics, not ethics

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.

Our theories of the eternal are as valuable as are those which a chick which has not broken its way read more

Our theories of the eternal are as valuable as are those which a chick which has not broken its way through its shell might form of the outside world.

A theory is no more like a fact than a photograph is like a person.

A theory is no more like a fact than a photograph is like a person.

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

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