Top 1200 Theory Quotes & Sayings

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory.

I had two passions when I was a child. First was to learn about Einstein's theory and help to complete his dream of a unified theory of everything. That's my day job. I work in something called string theory. I'm one of the founders of the subject. We hope to complete Einstein's dream of a theory of everything.

Evolution ... is really two theories, the vague theory and the precise theory. The vague theory has been abundantly proved.... The precise theory has never been proved at all. However, like relativity, it is accepted on faith.... On getting down to actual details, difficulties begin.

The most important single thing about string theory is that it's a highly mathematical theory, and the mathematics holds together in a very tight and consistent way. It contains in its basic structure both quantum mechanics and the theory of gravity. That's big news.

I believe without exception that theory follows practice. Whenever there is a conflict between theory and practice, theory is wrong. As far as I'm concerned, we make theories for what people have done.

Creationists have long held that evolutionary theory is atheistic; defenders of the theory do the theory no favor when they agree.

I think it laughable, frankly, that the physics community comes up with a theory for everything. There isn't one theory for everything. There is not one explanation. We may eventually have several theories that can tie things together nicely but there is not a single theory of everything.

I didn't know so well chess theory, the theory of chess openings. And so, of course I knew the theory, but not on the level of the best players, so this was my... this was always my weakness.

The first theory is that if we make the rich richer, somehow they will let a part of their prosperity trickle down to the rest of us. The second theory was the theory that if we make the average of mankind comfortable and secure, their prosperity will rise upward through the ranks.

In Darwin's theory, you just have to substitute 'mutations' for his 'slight accidental variations' (just as quantum theory substitutes 'quantum jump' for 'continuous transfer of energy'). In all other respects little change was necessary in Darwin's theory...

The standard theory may survive as a part of the ultimate theory, or it may turn out to be fundamentally wrong. In either case, it will have been an important way-station, and the next theory will have to be better.

The theory of chaos and theory of fractals are separate, but have very strong intersections. That is one part of chaos theory is geometrically expressed by fractal shapes.

A theory is only as good as its assumptions. If the premises are false, the theory has no real scientific value. The only scientific criterion for judging the validity of a scientific theory is a confrontation with the data of experience.

Our best theory of describing space at a fundamental level is probably string theory.

I have always been slightly suspicious of the theory of evolution because of its ability to account for any property of living beings (the long neck of the giraffe, for example). I have therefore tried to see whether biological discoveries over the last thirty years or so fit in with Darwin's theory. I do not think that they do. To my mind, the theory does not stand up at all.

There are two theories. There's one theory that Barack Obama wants to destroy the country and create a socialistic country. There is that theory, and I've read a lot. This isn't necessarily my theory. I personally think they're incompetent.

The supposed astronomical proofs of the theory [of relativity], as cited and claimed by Einstein, do not exist. He is a confusionist. The Einstein theory is a fallacy. The theory that ether does not exist, and that gravity is not a force but a property of space can only be described as a crazy vagary, a disgrace to our age.

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.

If you can't think of an observation that could disprove a theory, that theory simply isn't scientific.

Indeed, this epistemological theory of the relation between theory and experiment differs sharply from the epistemological theory of naive falsificationism.

The theory of natural selection is the centerpiece of The Origin of Species and of evolutionary theory. It is this theory that accounts for the adaptations of organisms, those innumerable features that so wonderfully equip them for survival and reproduction; it is this theory that accounts for the divergence of species from common ancestors and thus for the endless diversity of life. Natural selection is a simple concept, but it is perhaps the most important idea in biology.

The electron is a theory. But the theory is so good we can almost consider them real.

There is a new venue for theory, necessarily impure, where it emerges in and as the very event of cultural translation. This is not the displacement of theory by historicism, nor a simple historicization of theory that exposes the contingent limits of its more generalizable claims.

The more evolutionary theory gets called an atheistic theory, the greater the risk that it will lose its place in public school biology courses in the United States. If the theory is thought of in this way, one should not be surprised if a judge at some point decides that teaching evolutionary theory violates the Constitutional principle of neutrality with respect to religion.

After preliminary work by a number of other distinguished mathematicians and economists, game theory as a systematic theory started with von Neumann and Morgenstern's book, 'Theory of Games and Economic Behavior,' published in 1944.

If you're a physicist, for heaven's sake, and here is the experiment, and you have a theory, and the theory doesn't agree with the experiment, then you have to cut out the theory. You were wrong with the theory.

I hope we find evidence of dark matter in the lab and in outer space. This would go a long way to proving the correctness of string theory, which is what I do for a living. That is my day job. So string theory is a potentially experimentally verifiable theory.

The revolution which began with the creation of quantum theory and relativity theory can only be finished with their unification into a single theory that can give us a single, comprehensive picture of nature.

It is easy to obtain confirmations, or verifications, for nearly every theory-if we look for confirmations. Confirmations should count only if they are the result of risky predictions... A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice. Every genuine test of a theory is an attempt to falsify it, or refute it.

The theory of mechanism design can be thought of as the 'engineering' side of economic theory.

The aim of academic trade theory is to tell students, "Look at the model, not at how nations actually develop." So of all the branches of economic theory, trade theory is the most wrongheaded.

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.

When you look at the calculation, it's amazing that every time you try to prove or disprove time travel, you've pushed Einstein's theory to the very limits where quantum effects must dominate. That's telling us that you really need a theory of everything to resolve this question. And the only candidate is string theory.

As my colleague, the physical chemist Peter Atkins, puts it, we must be equally agnostic about the theory that there is a teapot in orbrit around the planet Pluto. We can't disprove it. But that doesn't mean the theory that there is a teapot is on level terms with the theory that there isn't.

I think it's a theory... the theory of evolution and I don't accept it as a theory.

The theory of our modern technic shows that nothing is as practical as theory.

Theory without practice is of little value, whereas practice is the proof of theory.Theory is the knowledge, practice the ability.

In these researches I followed the principles of the experimental method that we have established, i.e., that, in presence of a well-noted, new fact which contradicts a theory, instead of keeping the theory and abandoning the fact, I should keep and study the fact, and I hastened to give up the theory.

The beauty of string theory is the metaphor kind of really comes very close to the reality. The strings of string theory are vibrating the particles, vibrating the forces of nature into existence, those vibrations are sort of like musical notes. So string theory, if it's correct, would be playing out the score of the universe.

Well, it [evolution] is a theory, it is a scientific theory only, and it has in recent years been challenged in the world of science and is not yet believed in the scientific community to be as infallible as it once was believed. But if it was going to be taught in the schools, then I think that also the biblical theory of creation, which is not a theory but the biblical story of creation, should also be taught.

To understand the theory which underlies all things is not sufficient. Theory is but the preparation for practice.

Theories are not rejected by cirsumstantial evidence: it takes a theory to beat a theory.

No theory changes what it is a theory about; man remains what he has always been.

Human beings are pattern-seeking animals who will prefer even a bad theory or a conspiracy theory to no theory at all.

Creationists reject Darwin's theory of evolution on the grounds that it is "just a theory". This is a valid criticism: evolution is indeed merely "a theory", albeit one with ten billion times more credence than the theory of creationism - although, to be fair, the theory of creationism is more than just a theory. It's also a fairy story. And children love fairy stories, which is presumably why so many creationists are keen to have their whimsical gibberish taught in schools.

Catastrophe Theory is-quite likely-the first coherent attempt (since Aristotelian logic) to give a theory on analogy. When narrow-minded scientists object to Catastrophe Theory that it gives no more than analogies, or metaphors, they do not realise that they are stating the proper aim of Catastrophe Theory, which is to classify all possible types of analogous situations.

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.

Some claim evolution is just a theory. As if it were merely an opinion. The theory of evolution, like the theory of gravity, is a scientific fact. Evolution really happened. Accepting our kinship with all life on Earth is not only solid science. In my view, it’s also a soaring spiritual experience.

New knowledge has led to the recognition in the theory of evolution of more than a hypothesis. It is indeed remarkable that this theory has been progressively accepted by researchers, following a series of discoveries in various fields of knowledge. The convergence, neither sought nor fabricated, of the results of work that was conducted independently is in itself a significant argument in favor of this theory.

Moral theory develops from the divine command theory of medieval Christian philosophy, mixed up with a bit of ancient pagan virtue theory, to the purely secular moral sentiment and interpersonal reaction theories of Smith and Hume, to Kant's attempt to restore command theory but with something supersensible in the individual rather than God as the source of authority.

If what we regard as real depends on our theory, how can we make reality the basis of our philosophy? But we cannot distinguish what is real about the universe without a theory. It makes no sense to ask if it corresponds to reality, because we do not know what reality is independent of a theory.

There is the theory that all the living forms in the world have arisen from a single source which itself came from an inorganic form. This theory can be called the 'general theory of evolution,' and the evidence which supports this is not sufficiently strong to allow us to consider it as anything more than a working hypothesis.

The Theory of Relativity confers an absolute meaning on a magnitude which in classical theory has only a relative significance: the velocity of light. The velocity of light is to the Theory of Relativity as the elementary quantum of action is to the Quantum Theory: it is its absolute core.

I don't think about a theory of everything when I do my research. And even if we knew the ultimate underlying theory, how are you going to explain the fact that we're sitting here? Solving string theory won't tell us how humanity was born.

It is not enough for theory to describe and analyze, it must itself be an event in the universe it describes. In order to do this theory must partake of and become the acceleration of this logic. It must tear itself from all referents and take pride only in the future. Theory must operate on time at the cost of a deliberate distortion of present reality.

If the theory accurately predicts what they [scientists] see, it confirms that it's a good theory. If they see something that the theory didn't lead them to believe, that's what Thomas Kuhn calls an anomaly. The anomaly requires a revised theory - and you just keep going through the cycle, making a better theory.

When we meet a fact which contradicts a prevailing theory, we must accept the fact and abandon the theory, even when the theory is supported by great names and generally accepted.

Men follow their sentiments and their self-interest, but it pleases them to imagine that they follow reason. And so they look for, and always find, some theory which, a posteriori, makes their actions appear to be logical. If that theory could be demolished scientifically, the only result would be that another theory would be substituted for the first one, and for the same purpose.

I really don't like art where you need to know so much theory to understand. If the theory is removed, it doesn't do anything. That means that this work is an illustration of theory, and I don't believe in the power of the work itself.

And, partly, I had found that theory-structure was a superpower in helping one get what one wanted. As I had early discovered in school wherein I had excelled without labor, guided by theory, while many others, without mastery of theory failed despite monstrous effort. Better theory I thought had always worked for me and, if now available could make me acquire capital and independence faster and better assist everything I loved.