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. S

    Black Holes: Comparing Hawking & Kaku Theories

    Steven Hawking's / MKaku. Who's right about Black Holes? Does Prof. Steven Hawking's revised Theory of Black Holes rule out the existence of parallel universes? What about the Two Big Bang Theory by Dr. Raj Baldev, what implications does this theory have for M Theory.
  2. K

    Rank 2 and rank 1 field theories

    Can a rank 2 field be considered, in principle, to be the dot product of two rank 1 vector fields?
  3. B

    Theories of The Universe (and Reality)

    I find discussing the beginning and continuation of the universe one of the more interesting aspects of physics. Also the fact nobody really has any concrete proof as to much of where the universe is going, its boundaries, its expansion. Alot of people have their own ideas or beliefs, and i'd...
  4. B

    Exploring Alternative Theories of Dark Matter

    i'm interested in any alternative theories re: dark matter...is it possible that we simply have misunderstood gravity at these distances? it seems strange to me that we look for symmetry in the physical laws and so we see something we can't explain using the law of gravitation and our...
  5. S

    What is the current understanding of time in modern physics?

    Can someone please explain to me the current theories of Time? I have an idea I want to put forward to you all, but need to get a little groundwork in first. Based purely on what I learned in school, time is currently veiwed as linear, if so, how is this even possible? Much appreciated, thanks.
  6. A

    Application of quantum theories

    how are quantum theories applied to everyday life? in the physical, biological and chemical systems? like how does quantum theory explains the existence of parallel realities or universe?
  7. A

    Exploring the Different String Theories & Their Relationships

    Hi. Could someone please post a quick summary of which string theories are out there and how they relate to each other? I could only find partial information on this... Thank you.
  8. Y

    Why wouldn't this cylinder theory work?

    So don't be surprised if it's crap.In fact I know it's crap,I just need proper physics people to confirm it's crapness. :redface: Think of a hollow cylinder.There are springs on the bottom and top surfaces of the cylinder,meaning that if a ball was inside it would bounce back and forth.It is...
  9. N

    Alternative theories to General Relativity - great opportunity

    Gravity Probe B is due to be launched on Monday, 19 April, 2004. Many years in development, it is intended to provide good tests of "two extraordinary, unverified predictions of Albert Einstein's general theory of relativity." Many posters to PF have difficulties with GR; several have...
  10. R

    Two Big Bang Theory Vs Other Theories

    Hi, India rarely helps scientific advancement. Recently this country has made some wonderful advances in the field of missile technology and information technoloy. Their recognition has become strong now. Indians are now more popular in American due to outsourcing issue. Similarly some...
  11. T

    Five Super-string theories and one M-Theory = 6

    Is it strange that there are exactly the same number of superstring theories as there are known quarks?
  12. V

    Lon-local hidden variable theories?

    Bell thought that maybe non-local hidden variable theories might have something to say, even though local hidden variable theories have been shown to be unable to properly describe nature. well, what exactly would you mean by a non local hidden variable theory? where exactly does the...
  13. K

    Coral Castle - Exploring the Theories of Magnetism

    anyone familiar with this place in florida and the theories on magnetism the man whou built it espoused? http://www.fortunecity.com/greenfield/bp/16/coralcastle.htm
  14. K

    A brief history about development of String Theories

    --------------------------------------------------------------------- References: 1) Green M., Schwarz J., Witten E., Superstring Theory Vol. 1,2, Cambridge Univ. Press, 1987 2) S.Klimenko, V.Talanov, I.Nikitin ``Singularities on the world sheets of open relativistic strings'', Preprint...
  15. E

    Methods for Non-renormalizable theories?

    I have some doubts when dealing with non-renormalizable theories in fact le,s suppose we have a theory that is non-renormalizable for n>4 or n=4 then we could do the trick of triying to renormalize it in 4-e dimension being e a small parameter e>0 and after that take the limit e=0 (dimensional...
  16. M

    How does the public respond to new scientific theories?

    I am writing a paper on the Theory of Everything, and it's effect on mankind. I was wondering, how do you think the public would react if a theory of everything was discovered? How would the public accept a theory such as this (so large scale)? How would society change in general...
  17. M

    Number of Calabi-Yau Manifolds in Superstring Theories

    I want to know how many Calabi-Yau manifolds there are in each of the 5 superstring theories. Can you point me in the right direction?
  18. S

    Theories on why we fear death?

    not really philisophical more pyscological but anyone got any theories on why we fear death? isn't it supposed to be the solution to our pain? I've got my theorieso n it but i want to hear others...
  19. Loren Booda

    Are probabilistic theories necessarily falsifiable?

    Karl Popper asserted, in brief, that all theories are eventually falsifiable. What of a theory (quantum mechanics?) that embodies probabilities such that its truth and falsity are apparent a priori (a violation of Goedel's logic?) If probabilistic theories are proved necessarily falsifiable...
  20. Another God

    Contended Theories in Science And Who?

    Hi people. I have decided to go ahead with this on my own if no one helps me (nudge nudge, if anyone wants to help out on a rather large project, then feel free to email/PM me . Primarily my major concerns are webdesign, and possibly marketing/advertising aspects.) Anyway, the idea which I...
  21. A

    What is the foundation theory based on Energy and free software to back it up?

    As theories go, here's something new. A very simple foundation theory based on Energy, with free software to back it up. http://www.gamert.co.uk
  22. A

    Finding Physics Books on String Theories and Quantum Mechanics

    Hey guys! I was wondering, where could i find elucidating Physics books on String theories, quantum mechanics (QED, QCD, QFT, LQG, etc) and all related on the web? I've done some search, but all i could come up with was an electronics and engineering related forums, and that is not in my...
  23. E

    All theories in physics are incorrect

    all theories in physics are incorrect ! yes that's right. because 100% percent of the theories are using; approximations, incorrect perturbations, assumptions and so on. that is not valid for the behaviour of nature. physics is a kind of battle to understand the nature not to modify it...
  24. P

    Certain of dimensional fields as expressed in recent theories?

    Are we so certain of dimensional fields as expressed in recent theories? true we know of three for certain, but can it be possible the 10 or 11 maybe even more dimensions are mirroring the 3 principle dimensions?
  25. wolram

    Do string theories need gravitational radiation as in GR?

    do string theories need gravitational radiation as in GR?
  26. A

    What are the five string theories?

    i can not seem to find any good or relevant information on the five different string theories and how they differ from one another. i know of, and to the best of my ability try to understand 'basic' M-theory but am very strapped for info on the other theories and their specifics. if some one...
  27. J

    The consequences of Goedel's first incompleteness theorum for physical theories

    I didn't know whether to put this one in maths or physics, but I'm interested on what people on PFs think are the consequences of Goedel's first incomplteness theorum are for physical theories in general and in particular for the idea of a single comphrehensive theory that can describe all...
  28. T

    Looking for theories that describe time The more radical the better.

    Looking for theories that describe "time" The more radical the better. I'm trying to start up some interesting conversations about time at http://thinkbling.com/forum Please post any comments that you may have and want shared there. For now this will only be for this category.
  29. Ivan Seeking

    Moon-landing conspiracy theories weightless but persistent

    "Even today -- the 34th anniversary of the Apollo 11 landing, the first arrival by astronauts on the lunar surface -- there are people who think the whole program was a sham." http://www.siliconvalley.com/mld/siliconvalley/6350437.htm
  30. M

    Topological quantum field theories

    Chern-Simons theory is a 3d-TQFT and Crane-Yetter model is a 4d-TQFT There exist another Topological Quantum Field Theory apart of these two models?
  31. wolram

    Latest theories are for inter stellar propulsion

    can anyone tell me what the latest theories are for inter stellar propulsion, and has the problem of bone loss on long space flights been solved?
  32. E

    Conflict Between Theories: What's at Stake?

    I've heard that if one of these theories is correct then the other must be wrong. What exactly is the conflict between these two theories?
  33. M

    Crackpot Theories: Hidden Pearls Beyond the Mainstream

    I want that you tell me your crackpots ideas. I'm curious. Ideas against the mainstream, but that can be hidden pearls. There are some of mine: -For me the Universe is or an alive organism living in its own cosmos, or a creation/experiment of some kind of upper intelligence. I'm not sure what...
  34. B

    Is the MicroElectroMagnetoValence Theory Viable in Modern Physics?

    Here is a horribly misguided theory from my youth. I polished it up a bit and gave it a name. If anyone wants this theory, they can have it. MicroElectroMagnetoValence Theory Tenets:[list=1] The fundamental electric and magnetic charges are 1/6 of the elementary electric and magnetic...
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