What is Theories: Definition and 485 Discussions

A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may either be scientific or other than scientific (or scientific to less extent). Depending on the context, the results might, for example, include generalized explanations of how nature works. The word has its roots in ancient Greek, but in modern use it has taken on several related meanings.
In modern science, the term "theory" refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that scientific tests should be able to provide empirical support for it, or empirical contradiction ("falsify") of it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge, in contrast to more common uses of the word "theory" that imply that something is unproven or speculative (which in formal terms is better characterized by the word hypothesis). Scientific theories are distinguished from hypotheses, which are individual empirically testable conjectures, and from scientific laws, which are descriptive accounts of the way nature behaves under certain conditions.
Theories guide the enterprise of finding facts rather than of reaching goals, and are neutral concerning alternatives among values. A theory can be a body of knowledge, which may or may not be associated with particular explanatory models. To theorize is to develop this body of knowledge.The word theory or "in theory" is sometimes used erroneously by people to explain something which they individually did not experience or test before. In those instances, semantically, it is being substituted for another concept, a hypothesis. Instead of using the word "hypothetically", it is replaced by a phrase: "in theory". In some instances the theory's credibility could be contested by calling it "just a theory" (implying that the idea has not even been tested). Hence, that word "theory" is very often contrasted to "practice" (from Greek praxis, πρᾶξις) a Greek term for doing, which is opposed to theory. A "classical example" of the distinction between "theoretical" and "practical" uses the discipline of medicine: medical theory involves trying to understand the causes and nature of health and sickness, while the practical side of medicine is trying to make people healthy. These two things are related but can be independent, because it is possible to research health and sickness without curing specific patients, and it is possible to cure a patient without knowing how the cure worked.

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  1. wolram

    Cosmology: Exploring Mainstream Theories & Problems

    What are the (basic) problems with main stream theories of cosmology ? i do not want crackpotery, just what the people who work in or around the field think. I am unqualified to comment and will not, i hope moderators will keep this thead to the point.
  2. L

    Are All Scientific Theories Rooted in Empirical Observations?

    Is every scientific theory developed based on the facts obtained from careful observations/ experiments?
  3. E

    Dumb & Dumber: The Most Ridiculous Theories of Modern Times

    Hello everybody...it,s showtime:redface: :redface: why care for studying and being a serious scientist when you can make millions and fame by saying nonsenses?...heeere..we are our list of "Dumb & Dumber" of modern times... Bible secret codes:=oh yeah¡¡..yes you don,t need to get a...
  4. T

    Are there string theories based on unidirectional paths or strings?

    Are there string theories based on unidirectional paths or strings? I ask because the polysigned numbers have some strong unidirectional qualities. In a lattice environment loops are the only way to return to a source point. These loops are inherently unidirectional...
  5. T

    Are there Anti-Darwinism theories

    We've been learning about Darwins Evolution and Natural Selection theories in Class... And what I've wondered was if there were any Anti-Darwinism theories since I've seen some before yet I can't seem to find none online.. Any help will be appreciated thanks:)
  6. wolram

    Constructing Theories with Little Information

    How can anyone construct a theory with less than 5 % of the information, i know that you lot are very cleaver, but AE would be a dwarf to any one that can get a 100% ansewer from 5% information available.
  7. M

    Pdf's on newer theories and advancements in string theory

    can someone please link me to some new LEGAL pdf's on newer theories and advancements in string theory, qed, lqg etc.
  8. Q

    Is there any theories that state this?

    I'm really interested in philosphy now. Especially Solipsism and this one especially: Determinism is the philosophical proposition that every event, including human cognition and action, is causally determined by an unbroken chain of prior occurrences. No mysterious miracles or wholly random...
  9. Loren Booda

    Can science claim any unified theories?

    Will physics be first to attain unification, or has another branch of science already done so?
  10. Garth

    Alternative theories being tested by Gravity probe B

    The Gravity Probe B satellite has placed four (over redundant) gyroscopes in low polar Earth orbit to primarily test two predictions of General Relativity. The first effect being tested is (for the GP-B polar orbit) a N-S geodetic precession, caused by the amount a gyro 'leans' over into the...
  11. Math Is Hard

    What are some humorous comparisons between physical theories and women?

    ok, so it's a little sexist, but I thought it was clever. Ladies, just substitute boy for girl and he for she.. Physical theories as women By Simon Dedeo 0. Newtonian gravity is your high-school girlfriend. As your first encounter with physics, she's amazing. You will never forget...
  12. DrChinese

    Requirements of All Hidden Variable Theories

    I came across this article, which was published in the February 2004 issue of Physical Review A. "All quantum observables in a hidden-variables model must commute simultaneously" by James Malley Abstract: Under a standard set of assumptions for a hidden-variables model for quantum events...
  13. N

    Finding "Dynamical Symmetry Breaking in Quantum Field Theories

    Dear PF, Could anyone advise me where I can find the following book: Dynamical symmetry breaking in quantum field theories - Miransky, V.A. Is itt possible to download from somewhere? Cheers George
  14. N

    A proof that all signal local theories have local interpretations.

    This post is motivated by some of the discussion on the "Is QM inherently non-local" thread. The goal is to demonstrate that there is a local hidden interpretation possible for any signal local theory. This interpretation will be Bell local, but not Bell realistic. So, let's say we have a set...
  15. S

    Physics Theories: Do Photons Have Mass in Motion?

    hello its me again i have an other question. What does the latest physics theoreies say about this: Do photons have a mass if they are in movement ? i know that they have no mass if they not in movement. whats about deBroglie? Could you please give me an explanation which i do...
  16. DrChinese

    Does Bell's Theorem apply to non-local HV theories?

    Does Bell's Theorem apply to non-local HV theories? I know that Bell says it doesn't, and he has included logic intended to make separability a requirement. But consider this argument: What does it mean to say there are hidden variables? Einstein said: "I think that a particle must have...
  17. T

    What Are the Theories Behind Tooth Eruption?

    I am looking for some information on Tooth Eruption Theories. Thank you all. :)
  18. DrChinese

    A Paradox: Do LHV Theories Need the HUP?

    Here is one I am having trouble following. Can anyone help me through my confusion? Our setup is a normal Bell test using entangled photons created using spontaneous parametric down conversion (PDC). Such a setup uses 2 BBO crystals oriented a 90 degrees relative to each other. See for...
  19. A

    Theories about the beginning of the universe

    hello, i'm amit from israel, and i'd love to be an activated member in your forum. my first question - are there other theories about the beginning of the univers. except of "the big bang" (not religion)? thanks, amit
  20. N

    Thoughts on Einstein’s Theories

    I believe Einstein said, 1.There are four dimensions to space, the normal three plus time. 2. Speed of light cannot be obtained due to an object traveling at such speeds gaining mass. The faster it goes, the more mass gained, until it reaches “infinite mass”. 3. Mass and Energy are pretty much...
  21. vincentm

    Omega pointe and the Big crunch theories

    Can someone explain the Omega pointe to me? In regards to the theory of the universe collapsing?
  22. wolram

    Gravity Debate: Unanswered Questions on String/Loop Theories

    As things seem a bit slow of late i wonder if anyone would give an over view of the gravity debate, i know the Higgs is still elusive and the graviton remains un found, no axions as yet, etc, etc, but what does this mean to string and loop theories?
  23. K

    Time in time-dependent theories

    I have this odd question. I'm not a physicist, just a computer scientist in training with a broad range of interests. So excuse me if I get something completely wrong. There seems to be a bunch of theories in physics that basically say that some or all universal "constants" are not in fact...
  24. D

    M-Theory is a theory which 'combines' the five superstring theories

    Waddup guys. To my understanding M-Theory is a theory which 'combines' the five superstring theories and supergravity.Also i understand that matematics is not yet advanced enough to make it work(or so I've been told) I am still not sure how this theory is meant to end up as a theory of...
  25. G

    Is there any truth to the theories on time travel?

    Anyone know any cool new theories about time travel?
  26. M

    What is the History of Aether Theories and their Mathematical Basis?

    Heya, I am writing a paper at the moment on aether theories from an historical perspective. I am mostly interested in the mathematical basis of aether theories starting from when Maxwell unified electric and magnetic fields. What I would like to know is if anybody has any idea where to...
  27. L

    New theories of professor Valitov after Einstein

    Here I'd like to present theories of professor of physico-chemistry, Ph.D. Najip Valitov from Russia, who discovered new theories after Einstein. Part of his discoveries are described in his web-page: [PLAIN]www.bashedu.ru/ValitovNKH.htm[/URL] In 1972 professor Valitov, who lived in the...
  28. C

    Failure theories and uniaxial testing

    in all the failure theory we compare the stress in the structure to the yield stress in the uniaxial testing. How this is valid? for example in a structure the max normal stress is sigma x. and we compare this with the maximum normal stress in a uniaxial tension test. in vonmises also...
  29. matthyaouw

    Favorite crackpot theories.

    I'm sure you've all heard a lot of them in your time, so share with me some of the most rediculous ones, or ones that amuse you most. I just stumbled across this little beauty: http://www.nov55.com/geol.html The person explains in vaguely how soil formation through the means of breakdown...
  30. S

    What are the main macroeconomic theories and where can they be found?

    Does anyone know of any comprehesive sites featuring ALL of the following: the Keynesian theory, Monetarist theory, and the Rational Expectations theory? Any ones that compare/contrast them would be excellent. Thanks again.
  31. Ivan Seeking

    Explore the Science of Sci-Fi: Relativity, Chaos & Superstring Theories

    http://www.scifiscience.co.uk/index.htm From Astronuc. This gives a very brief introduction to Relativity, Chaos, and Superstring Theories, and a few other Sci-Fi Science concepts.
  32. wolram

    Testing gravity theories with Anti atoms

    http://xxx.sf.nchc.gov.tw/pdf/hep-ex/0503034 This paper is a review of anti hydrogen production, and how it could be used to test gravity theories.
  33. D

    Symmetry, groups and gauge theories in the standard model

    This is my (limited) understanding of particle physics: In particle physics gauge symmetries play an important role. To allow for massive gauge bosons this symmetry is broken. The theory of weak interactions can be derived from a local SU(2) symmetry, and quantumchromodynamics from a local SU(3)...
  34. V

    Can Neutrinos Decay? Examining Proton Decay Theories

    some theorist predicts proton can decay, since the decay of proton does not violate any fundemantal conservation law. My question is, could neutrino decay? How come I have never heard of anyone say neutrino could decay?
  35. matthyaouw

    Problems with climate change theories.

    I am looking to learn about the major flaws with our current theories and data on climate change, particularly in terms of the ice ages. Any examples of inconsistencies or problems with data, or any other information you could give me would be much appreciated. Thanks, Matt.
  36. quantumdude

    Aether theories which are experimentally indistinguishable from SR.

    From John Baez’ page on the experimental basis of Special Relativity, he says that: and My question pertains to the remarks in blue: aether theories that are experimentally indistinguishable from SR. Where are these theories published? One member (Yogi) makes reference to the so-called...
  37. S

    Exploring Complex Numbers: Sources & Theories

    I've been attending at high school and I have some ideas about complex numbers. I shared my thoughts with my math teacher. He decided to search. I want to make sure if none have thought them so I need some information about complex numbers. Could you offer me some written sources and the...
  38. J

    WALKING ON WATER? any theories how

    well there are many stories of human beings being able to do things that we would only think are in our favorite comic books but let's focus on walking on water. from jesus to the monk of tibet, there are lots of stories about human beings walking on water, so is there any theory as to how this...
  39. P

    Are Quantum Mechanics and Relativity Logically Compatible Theories?

    I've often read that quantum mechanics and relativity theory are logically incompatible theories, meaning that both theories cannot be true. Can anyone use mathematics to prove that? Thanks, King
  40. C

    Cosmological relativity theories

    If a galaxy is 1 billion light year far from us and if for us big bang did happen 13 billion years ago then when it did happen for that galaxy ? Pure guess will predict the answer 12 billion years, but what the observer on that galaxy will say about us ? will not he predict that we are...
  41. T

    Should You Share Your Revolutionary Science Theory Online?

    Greetings , my friends! Haven't asked that question in public before but for now I thought it might be beneficial to do so since You guys know stuff around here. What do to if You've came to a some kind of science theory? ...new therorem in maths , law in physics or alike which seems...
  42. I

    Conspiracy Theories: Check & Share Your Thoughts

    check this out http://www.prisonplanet.tv/audio/091204hilton.htm and this http://www.freedomunderground.org/memoryhole/pentagon.php#Main tell me what you think
  43. G

    General Question about Einstein's Theories.

    Which, if any, of Einsteins models and theories have been replaced by more advanced or precise ones? The only thing that comes to mind was Einstein's "greatest blunder", the cosmological constant. But hasn't that even found its was back into the equations? Thanks, Glenn
  44. marcus

    Planck scale Lorentz-symmetry test theories Amelino-Camelia

    "Planck scale Lorentz-symmetry test theories" Amelino-Camelia new paper by Giovanni A-C http://arxiv.org/abs/astro-ph/0410076
  45. A

    What is the idea behind the string theories?

    hello, from sometime in past i was in contact of the string theories. But one thing that clicked in my mind that how does the physicst started the idea of the string theories (all of them) like Newton formulated the law of gravitational force after he observed the motion of the moon...
  46. humanino

    Mass gap in Yang-Mills theories

    Could someone rephrase in a short and casual manner the famous Millenium Problem of the Clay Math institute ? http://www.claymath.org/millennium/Yang-Mills_Theory/ Thank you for help !
  47. N

    Theories of Relativity: Analogon

    An interesting observation I made while in chemistry lab was that volatile liquids follow a type of "relativity theory." Imagine temperature (T) as the speed of light (C) in this thought experiment. So, as the heated water approaches T>100 degrees Celsius, the water converts to another state...
  48. J

    Learn More About Relational Theory: Get Tips Here

    Items in a data set or group are divided into pairs with specific relationships between each pair. In this way a degree of order is introduced into the set. I understand this can be done with the entire universe but where do I find out more?? Any suggestions would be helpful.
  49. E

    Can we solve the problem of renormalization in quantum gravity?

    why can we renormalize some theories but others not?..in fact what wo7uld happen if we apply renormalization group method,or Feynmann,s renormalization program to quatnum gravity (non renormalizable theories). I also found that http://arXiv.org/abs/hep-th/9507067 they claim to have...
  50. J

    Relational Theory Overview: Resources for General Descriptions

    Any suggestions on where I can find general descriptions of relational theories please?
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