Theory Sayings and Quotes

Below you will find our collection of inspirational, wise, and humorous old theory quotes, theory sayings, and theory proverbs, collected over the years from a variety of sources.


Experience without theory is blind, but theory without experience is mere intellectual play.     

Immanuel Kant

Never abandon a theory that explains something until you have a theory that explains more.     

John McCarthy

Theory without data is myth: data without theory is madness.     

Phil Zuckerman

Theories are private property, but truth is common stock     

Charles Caleb Colton

We must alter theory to adapt it to nature, but not nature to adapt it to theory.     

Claude Bernard

Experience by itself teaches nothing...Without theory, experience has no meaning. Without theory, one has no questions to ask. Hence without theory there is no learning.     

W. Edwards Deming

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

Yogi Berra

A good scientific theory is one which is falsifiable, which has not been falsified.     

Richard Dawkins

Theory is worth but little, unless it can explain its own phenomena, and it must effect this without contradicting itself; therefore, the facts are sometimes assimilated to the theory, rather than the theory to the facts.     

Charles Caleb Colton

It is the theory which decides what can be observed.     

Albert Einstein

The truth of a theory is in your mind, not in your eyes.     

Albert Einstein

The difference between theory and practice is larger in practice than the difference between theory and practice in theory.     

Jan L. A. van de Snepscheut

Leave your theories. All theories, you see, even those of virtue, are bad, foolish, mischievous.     

Romain Rolland

The moment a person forms a theory, his imagination sees in every object only the traits which favor that theory.     

Thomas Jefferson

Theories are usually the over-hasty efforts of an impatient understanding that would gladly be rid of phenomena, and so puts in their place pictures, notions, nay, often mere words.     

Johann Wolfgang von Goethe

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

Edward W. Howe

Generally the theories we believe we call facts, and the facts we disbelieve we call theories.     

Felix Cohen

A theory must be tempered with reality.     

Jawaharlal Nehru

All theories are legitimate, no matter. What matters is what you do with them.     

Jorge Luis Borges

All theory, dear friend, is gray, but the golden tree of life springs ever green.     

Johann Wolfgang von Goethe

Theory and practice sometimes clash. And when that happens, theory loses. Every single time.     

Linus Torvalds

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

E.W. Howe

Every theory is a self-fulfilling prophecy that orders experience into the framework it provides.      

Ruth Hubbard

Theories are neither hunches nor guesses. They are the crown jewels of science.     

Carl Zimmer

Those who say theory and practice are two unrelated realms are fools in one and scoundrels in the other.     

Ayn Rand

The theory of rights enables us to rise and overthrow obstacles, but not to found a strong and lasting accord between all the elements which compose the nation.      

Giuseppe Mazzini

Theory helps us to bear our ignorance of fact.     

George Santayana

There is a distinction, but no opposition, between theory and practice. Each to a certain extent supposes the other. Theory is dependent on practice; practice must have preceded theory.     

Sir William Hamilton

An ounce of action is worth a ton of theory.      

Friedrich Engels

No theory is good unless it permits, not rest, but the greatest work. No theory is good except on condition that one use it to go on beyond.     

Andre Gide