An ounce of action is worth a ton of theory.

An ounce of action is worth a ton of theory.

[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.

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

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

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

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

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.

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.

Many things difficult to design prove easy to performance.

Many things difficult to design prove easy to performance.

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.

A theory has only the alternative of being right or wrong. A model has a third possibility - it may read more

A theory has only the alternative of being right or wrong. A model has a third possibility - it may be right but irrelevant.