My theory has always been, that if we are to dream, the flatteries of hope are as cheap, and pleasanter, than the gloom of despair.
Thomas Jefferson

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

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

I have just got a new theory of eternity.
Albert Einstein

There could be no fairer destiny for any physical theory than that it should point the way to a more comprehensive theory in which it lives on as a limiting case.
Albert Einstein

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

The things that will destroy America are prosperity-at-any-price, peace-at-any-price, safety-first instead of duty-first, the love of soft living, and the get-rich-quick theory of life.
Theodore Roosevelt

My theory of evolution is that Darwin was adopted.
Steven Wright

An ounce of action is worth a ton of theory.
Ralph Waldo Emerson

I have a theory about the human mind. A brain is a lot like a computer. It will only take so many facts, and then it will go on overload and blow up.
Erma Bombeck

My theory on housework is, if the item doesn't multiply, smell, catch fire, or block the refrigerator door, let it be. No one else cares. Why should you?
Erma Bombeck

In order to govern, the question is not to follow out a more or less valid theory but to build with whatever materials are at hand. The inevitable must be accepted and turned to advantage.
Napoleon Bonaparte

Classic economic theory, based as it is on an inadequate theory of human motivation, could be revolutionized by accepting the reality of higher human needs, including the impulse to self actualization and the love for the highest values.
Abraham Maslow

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.
Leonardo da Vinci

The whole theory of the universe is directed unerringly to one single individual.
Walt Whitman

I have a theory that the truth is never told during the nine-to-five hours.
Hunter S. Thompson

The theory of Communism may be summed up in one sentence: Abolish all private property.
Karl Marx

Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?
Stephen Hawking

If we do discover a complete theory, it should be in time understandable in broad principle by everyone. Then we shall all, philosophers, scientists, and just ordinary people be able to take part in the discussion of why we and the universe exist.
Stephen Hawking

A universe with a God would look quite different from a universe without one. A physics, a biology where there is a God is bound to look different. So the most basic claims of religion are scientific. Religion is a scientific theory.
Richard Dawkins