Theoretical Definition and 1000 Threads

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. Simfish

    Why do applied explanations sometimes seem more confusing than theoretical ones?

    Is it common to find the "applied" explanations more confusing than the "theoretical" Is it common to find the "applied" explanations more confusing than the "theoretical" ones? E.g. thermodynamics seems VERY confusing if I try to learn it from engineering textbooks, but VERY understandable...
  2. H

    [Theoretical] Physics Ph.D. application

    I hope to apply for a Ph.D. place in 2012; is it possible to send off written papers [as if to write extended articles] as part of the application, to demonstrate competence? I am worried that otherwise the grades for the various modules of my Physics degree that won't end up as my intended...
  3. T

    Physics Difference between a Theoretical Physicist and an Astrophysicist?

    What are the difference? What does each one specialize in? I've tried looking on google but I can't really find anything that explains exactly what they do.
  4. S

    What Skills Are Essential for Success in Theoretical Physics?

    do you khow definintion of theoretical physics? in this branch of physics; what skills should we have?
  5. P

    Exploring Hot Research in Theoretical Quantum Optics/Cavity QED

    OK guys Can anyone tell me some hot research problems in theoretical quantum optics/cavity QED right now ?
  6. O

    Is it plausible to do theoretical research while working?

    I really like physics, and I really like engineering. I like theory and I like building things and understanding how things work and all that jazz. So it's always been a tossup, hence I'm working on 2 BS degrees in Physics and EE ( the reason is because i couldn't imagine not doing either...
  7. O

    Quick question about theoretical physics research

    What is it? By that I mean what does it consist of? My understanding is that experimental physics research is performing experiments and recording observations, then drawing conclusion from that. Is theoretical physics research then just locking yourself in a room and posing problems...
  8. P

    Physics Can I Switch to Theoretical Physics? A PhD Student's Confusion

    Hi. I'm currently a 4th year phd student in astrophysics, studying compact stars. I'm from China and am now an exchange student in US. What I'm asking is: if I really have more interest in theoretical physics, do I still have a chance of entering the field? I'm now in a very confusing stage...
  9. M

    Modules for Theoretical Physics

    Right so I'm a math major but what I really want to be is a theoretical physicist. 3rd and 4th year is when everything gets very specified, and I'm wondering which of the following modules would be most useful for that path? Here are the modules. Only 6 can be chosen from each term...
  10. P

    Programs Will a PhD in Theoretical Chemistry restrict my future post-doc to chemistry?

    I'm thinking of doing a PhD in http://www.ucl.ac.uk/chemistry/vacancies/adverts/studentships/2011/Zwijnenburg_2011_1" . I come from a physics background and have a MSci Mathematical Physics. I'm confident that this PhD is suitable for me, and all I have to do now is accept the offer, but I...
  11. A

    Physics ME to Experimental or Theoretical Astrophysics?

    Hi guys, I have a few questions that's been bugging me for a while and finally decided to post it in hopes to get some feedback. Tech background: Mechanical engineer BS, will be getting MASc. in ME as well. Although my degree is ME, my focus in undergrad had been on CNC machines/CAD and my...
  12. A

    Theoretical Yield of CaCO3: Calculate & Round

    Homework Statement What is the theoretical yield of calcium carbonate if 2.07 grams of calcium chloride dihydrate reacts with excess sodium carbonate according to the balanced chemical reaction shown below? Homework Equations Please use molar mass values calculated and rounded to the...
  13. camipol89

    Difference between theoretical astrophysics and theoretical physics

    Is there a difference between theoretical astrophysics and theoretical physics applied to astrophysics? Thanks
  14. B

    Calculating Theoretical Yield for Copper Reactions: Help with Homework

    Homework Statement Here's the measurements from my expirement. (reaction 1) 0.548 g Cu (s) 4.0 mL HNO3 100 mL DI water (reaction 2) 30 mL 3.0 M NAOH (reaction 3) nothing was added. (reaction 4) 200 mL of DI water 15 mL of 6.0 M HCl (reaction 5) 2.095 g Zn 10 mL 6M HCl 5...
  15. D

    Special Relativity: Theoretical Questions

    I am still trying to understand a few things about special relativity. Lets say I am traveling at the speed of light on a space ship. 1. Would this speed allow time to stand still for me? 2. Will this cause me to never age? 3. If I travel faster, would I be able to travel to the...
  16. R

    Theoretical Physics: Most Precise & Powerful Science

    "Theoretical physics is the most precise predictive powerful area of science we know The title is a quote of Prof. Neil Turok of The Perimeter Institute in Canada1. I always had the impression physicists tend to "lie" or diminish mathematical rigor. My point - I always thought mathematics is...
  17. U

    Physics Mechanical Eng to Theoretical Physics

    Hai, Could u give a opinion for my Higher Studies from Mechanical to Theoretical Physics, currently I am doing my 3rd year and writing GRE on July 2011 .I could not come to Decision whether to take Mechanical or Theoretical Physics.I hav done a couple of good projects in mechanical...
  18. J

    Physics Being a good theoretical physicist

    Hello everyone. I'm a 11th grader who plans on becoming a theoretical physicist. In fact, for most of the time, the only thing that goes in my head is trying to think of an idea to find a better alternative to quantum mechanics, as I feel that it is not in accordance with nature. I have the...
  19. A

    Physics How do theoretical physicists conduct research?

    Is it mostly trying to coming up with equations, solving them, reading etc.? Do they use computers a lot or can the work they do be done simply with a pen and paper?
  20. J

    Help with a logical derivation of set theoretical statement

    Homework Statement This is actually from the proof of Dedekind's cut in Rudin's Principles of Mathematical analysis on the page 19. It says when \alpha\in\mathbb{R} (\alpha is a cut) is fixed, \beta is the set of all p with the following property: There exists r>0 such that...
  21. V

    Reviewing Mechanics: A Course of Theoretical Physics Volume 1

    How is "Mechanics; a course of theoretical physics volume 1", by Landau and lifshitz? I have recently bought Volume 2 of this series (the classical theory of fields) because it was recommending for an undergrad course I'm following. I was wondering how good this first part was. I'm mainly...
  22. A

    Where can I find theoretical isochrones?

    I am currently doing a 2nd year lab report and need some theoretical isochrones to work out the age of some clusters, M15 and H+chi persei (Double Cluster). I was going to use Seiss: http://www-astro.ulb.ac.be/~siess/server/iso.html But it doesn't seem to be online :( What alternatives...
  23. N

    Prerequisites for Theoretical or Particle Physics

    Hi my name is Nick, I was wondering exactly what I would need, or could begin learning now that would help me get into the field of either Theoretical or Particle Physics. I'm a senior in high school and have gotten interested in physics, specifically those two areas. As a result I have...
  24. E

    Astrophysics and theoretical physics

    Hello, I was wondering what's the difference between an astrophysicist and a theoretical physicist? Cause they seem like the same thing?
  25. B

    (Theoretical) Repurposing of electric elevator motor

    Greetings, I am writing a Fan Fiction for someone and had a technical question. I like to do as much research as possible and have my "work" be as accurate/realistic as possible, so here I am. I know this might not be the place to ask it, but if you know of any place more suitable I wouldn't...
  26. FeDeX_LaTeX

    Physics What is a Theoretical Physicist?

    Hello; What is a theoretical physicist? Is it someone who studies theoretical physics? If so, what is theoretical physics? If I say I am a theoretical physicist, what do I do? Does this mean that I don't do any experimentation to test my hypotheses as that would make me an experimental...
  27. E

    Book on theoretical nuclear physics

    Can you recommend a good book on the theoretical side of nuclear physics?
  28. S

    Programs PHD in Theoretical particle physics/cosmology

    Hi i know there's been many threads on this but i looked at them and they don't answer my Q's Basiaclly I am doing an Mphys Physics Degree in the UK . My university is very experimental, basically all lab work and projects experimental and only theoretical research that is interesting is...
  29. M

    Theoretical Gunshot with Thunder

    Hey, I found this site while studying for my physics midterm, but then I can across an interesting question in a video game. In Battlefield:Bad Company 2, there is a mission where you have to snipe somebody but do it so nobody hears a gunshot, you accomplish this by firing when you see...
  30. D

    Mathematics for Theoretical Ecology?

    Hi, I just found this great forum and I am hoping to get some advice. I am starting an ecology degree with the hope of, one day, getting into grad school. I don't know yet what type of research I would like to do but I want to keep the door to theoretical work open. As my math background is...
  31. S

    Academic guidance in theoretical physics

    Hello everyone, been reading different articles on here for a while but finally decided to sign up as I needed some advice with regards to univesity. Im looking to study theoretical physics at Glasgow University starting fall 2012, however I am confused over my choice of courses. Glasgow...
  32. F

    Schools College freshman, interested in theoretical neuroscience

    So I'm currently a freshman at UPenn. I came in wanting to major in physics & math and go on to grad school in particle physics. However I've been a bit disillusioned since, by how esoteric the math required for it was and by the fact that there are barely any positions in academia for it. And...
  33. D

    Physics Theoretical Physicist: A Normal Day & Salary

    I've recently been getting interested in physics and astronomy and have even thought about going to school and starting a career in physics. Of course, this is just consideration and I'm going to learn more about it and different jobs before I even think about taking any kind of step further. Of...
  34. K

    Occam's razor and theoretical physics

    Hello Forum, I have a general interest in theoretical physics and my knowledge and understanding extends no further than what is presented in popular layman's texts. I have two questions which may be more philosophical - if this is the incorrect forum for these questions, please direct me...
  35. J

    Theoretical Question: Mass of Earth

    I was just curious about this. Are humans counted in the mass of the Earth? If so as the population increases does the masss of the Earth also increase? I think it wouldn't due to humans technecally being made from the Earth. We are carbon, nitrogen, hydrogen, and oxygen from the Earth so when...
  36. H

    Exploring the T-Line Theory: Can it Explain the Nature of Time?

    Question has been answered, thanks
  37. D

    Lagrange Multipliers: A theoretical question and an example

    Hello physicsforums community. I have recently learned about Lagrange multipliers and have been given three problems to solve. Could you guys please go over my work and see if I have the gist of it? One question, a theoretical one, I have no idea how to begin. Any advice regarding this would be...
  38. S

    What Did the Universe Look Like from the Big Bang to Now?

    I am asking for a sort of "artists rendition" of what the universe looked like from the Big Bang onward -- what our universe would have "looked like" over time to a theoretical observer. I've seen plenty of pics like http://en.wikipedia.org/wiki/File:WMAP_2010.png and plenty of animations...
  39. A

    What is the Theoretical Range of a Rocket at 79 Degrees?

    Homework Statement My rocket was angled at 79 degrees from the vertical, I calculated its maximum vertical height to be 60 meters, The total flight time was 7 seconds Experimental horiz distance is 40 yds (should be 36.6 meters) Homework Equations This is part of my problem, I am...
  40. P

    Is my view of Theoretical physics romanticized?

    Hey guys. I am a final year high school student and have lately been researching a career in Mathematics/Theoretical physics. Most recently i have come to the conclusion that: 1. I am not as gifted in mathematics as i thought 2. I do not enjoy PURE mathematics as much as i once believed i did...
  41. G

    Greatest Theoretical Physicists of 20th Century?

    I would have to speculate they are: Albert Einstein Marie Curie Niels Bohr Erwin Schrodinger Wolfgang Pauli Paul Dirac Enrico Fermi Edwin Hubble Robert Oppenheimer Richard Feynman Julian Schwinger Sin-Itiro Tomonaga Chen Ning Yang Abdus Salam Steven Weinberg Sheldon Glashow...
  42. P

    What Fields Can a Theoretical Physicist Focus on Besides String Theory?

    Ok, i have come to a realisation that my interests revolve not around pure mathematics (as i once thought) and more around theoretical physics, some people would claim that they merge into one at times, and that leads on to my question. If i wanted to be a theoretical physicist (rather than an...
  43. T

    Maths problem for a theoretical method of travelling time.

    I am trying to portray a method of time travel on another thread. I have no maths. It's NOT helping. I was wondering if anyone would care to venture into the project? My idea is as such: Based on the fact that time is variable to gravity. (See link) I suggest that should gravity be...
  44. R

    Physics Smart enough for theoretical physics?

    Is there a Litmus test I could use to see if I'm cut out for theoretical physics? I'm a first year undergrad, and thus far things have been going well. The classes aren't hard, my grades are good, and I'm finding the time to read some more advanced texts. But there's also fifty other people...
  45. Z

    Considering a switch to theoretical physics

    Considering a "switch" to theoretical physics I'm a math major with 5 semesters left as an undergraduate. My math "profile" is very strong: lots of graduate classes (commutative algebra and algebraic geometry, homological algebra, higher homotopy theory and homology theory, representation...
  46. J

    I'm thinking of entering the field of Theoretical Physics

    First off, I'd like to introduce myself as this is my first post. My name is John, I'm 17, unemployed and science/technology has kept me entertained and happy for most of my life. With that said, I have a few questions. The first one is for the physicists (w/ a job) on this forum. What's a...
  47. I

    Tricking Theoretical Thinking Question

    Tricky Theoretical Thinking Question Homework Statement Two equal-weight kids each hang from the ends of a rope passing over a weightless, frictionless pulley. If one child accelerates up the rope, what happens to the other? Homework Equations The Attempt at a Solution At...
  48. M

    Physics Theoretical Physics Career: Where to Start?

    I am very interested in theoretical physics and would like a careers in it. However, I'm not really sure about where to get a job in it or what kind of job. Can anyone help me figure this out? Thank you so much!.
  49. N

    Theoretical question on solutions

    we have y'=f(x)y+g(x) when f and g are continues on (a,b). and there is a point x_0 for which g(x_0) differs zero.suppose that u_1 and u_2 are solution to the equation on (a,b) .and if for some c,d d*u_1+c*u_2 is also a solution thn we cn conclude that : (we need to choose one of the options)...
  50. N

    Theoretical question on cyclic function

    a(x) is continues on R with cycle T ,a(x+T)=a(x) u(x) is non trivial soluion of y'=a(x)y \lambda=\int_{0}^{T}a(x)dx which of the following claims is correct: A. if \lambda>0 then \lim_{x\rightarrow\infty}u(x)=\infty B. if \lambda=0 then u(x) is a cyclic function i don't have...
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