Theory Quotes

500+ Sourced quotes

The Theory hardly rose to the dignity of a Working Hypothesis. Clearly more Facts were needed.

All human activity is prompted by desire. There is a wholly fallacious theory advanced by some earnest moralists to the effect that it is possible to resist desire in the interests of duty and moral principle. I say this is fallacious, not because no man ever acts from a sense of duty, but because duty has no hold on him unless he desires to be dutiful. If you wish to know what men will do, you must know not only, or principally, their material circumstances, but rather the whole system of their desires with their relative strengths.

Bertrand Russell

My pacifism is an instinctive feeling, a feeling that possesses me because the murder of men is disgusting. My attitude is not derived from any intellectual theory but is based on my deepest antipathy to every kind of cruelty and hatred.

Albert Einstein

In this sense, the theory of the Communists may be summed up in the single sentence: Abolition of private property.

Einstein's theory of relativity is probably the greatest synthetic achievement of the human intellect up to the present time.

Bertrand Russell

In theory there is nothing to hinder our following what we are taught; but in life there are many things to draw us aside.

Coincidences, in general, are great stumbling blocks in the way of that class of thinkers who have been educated to know nothing of the theory of probabilities- that theory to which the most glorious objects of human research are indebted for the most glorious of illustration.

Edgar Allan Poe

Such simple instincts as bees making a beehive could be sufficient to overthrow my whole theory.

I was sitting in a chair in the patent office in Bern when all of a sudden a thought occurred to me: 'If a person falls freely he will not feel his own weight.' I was startled. This simple thought made a deep impression on me. It impelled me toward a theory of gravitation.

Albert Einstein

That is the way of the scientist. He will spend thirty years in building up a mountain range of facts with the intent to prove a certain theory; then he is so happy with his achievement that as a rule he overlooks the main chief fact of all-that all his accumulation proves an entirely different thing.

Time is that wherein there is opportunity, and opportunity is that wherein there is no great time. Healing is a matter of time, but it is sometimes also a matter of opportunity. However, knowing this, one must attend to medical practice not primarily to plausible theories, but to experience combined with reason. For a theory is a composite memory of things apprehended with sense perception.

The theoretical scientist is compelled in an increasing degree to be guided by purely mathematical, formal considerations in his search for a theory, because the physical experience of the experimenter cannot lift him into the regions of highest abstraction.

Albert Einstein

I have no theory about dreams. I do not know how dreams arise. On the other hand, I know that if we meditate on a dream sufficiently long and thoroughly – if we take the boat with us and turn it over and over – something almost always comes out of it.

We are a moderate, pragmatic people, more comfortable with practice than theory.

The subject of this book is the structure of space-time on length-scales from 10-13cm, the radius of an elementary particle, up to 1028cm, the radius of the universe.... we base our treatment on Einstein's General Theory of Relativity. This theory leads to two remarkable predictions about the universe: first, that the final fate of massive stars is to collapse behind an event horizon to form a 'black hole' which will contain a singularity; and secondly, that there is a singularity in our past which constitutes, in some sense, a beginning to the universe.

Stephen Hawking

In war, theory is all right so far as general principles are concerned; but in reducing general principles to practice there will always be danger. Theory and practice are the axis about which the sphere of accomplishment revolves.

Napoleon I of France

We never thought, sitting in my office on those afternoons, discussing Voltaire and Ingersoll, that we would ever be brought to this, did we? You, the atheist whom the mere sight of a church spire on the sky could enrage; and I who have never been able to divorce myself from reason enough even to accept your pleasant and labor-saving theory of nihilism.

William Faulkner

Europe is so well gardened that it resembles a work of art, a scientific theory, a neat metaphysical system. Man has re-created Europe in his own image.

By abstaining from all definite content, whether as formal logic and theory of science or as the legend of Being beyond all beings, philosophy declared its bankruptcy regarding concrete social goals.

Theodor W. Adorno

How is Marxist-Leninist theory to be linked with the practice of the Chinese revolution? To use a common expression, it is by "shooting the arrow at the target". As the arrow is to the target, so is Marxism-Leninism to the Chinese revolution. Some comrades, however, are "shooting without a target", shooting at random, and such people are liable to harm the revolution.

Geometry has been, throughout, of supreme importance in the theory of knowledge.

Bertrand Russell

I believe in intuitions and inspirations. I sometimes feel that I am right. I do not know that I am. When two expeditions of scientists, financed by the Royal Academy, went forth to test my theory of relativity, I was convinced that their conclusions would tally with my hypothesis. I was not surprised when the eclipse of May 29, 1919, confirmed my intuitions. I would have been surprised if I had been wrong.

Albert Einstein

If we have a correct theory but merely prate about it, pigeonhole it and do not put it into practice, then that theory, however good, is of no significance.

I believe what really happens in history is this: the old man is always wrong; and the young people are always wrong about what is wrong with him. The practical form it takes is this: that, while the old man may stand by some stupid custom, the young man always attacks it with some theory that turns out to be equally stupid.

G. K. Chesterton

The theory of the permanent revolution, in contradiction to the theory of socialism in one country, was recognized by the entire Bolshevik party during the period from 1917 to 1923.