What is Theoretical: Definition and 1000 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. J

    String Theory and Theoretical vs. Mathematical Physics

    Hello, I have a question about the the difference between mathematical physics and theoretical physics in general and about the difference between the MSc Theoretical and Mathematical Physics courses at Edinburgh in particular. I am planning to apply, however I am not sure which of the two...
  2. W

    Physics How to go about pursuing career in theoretical physics

    I am a year 1 University Physics student and am interested in pursuing a career (if i make the cut) in theoretical physics (in particle physics/cosmology). The thing is, I know precious little about this field (but enough to get the brain juices flowing) hence the following queries: a) What is...
  3. Brent Lingenfelter

    Teen Struggling to Become a Theoretical Physicist?

    I'm 14 years old, and I would like to become a Theoretical Physicist. There is an issue though and I don't know what to do. The problem is in math/science "I have to take biology this year :(" class I am so bored they take the fun out of learning. Also everything is way way too slow I am...
  4. E

    Physics Can you get two PhDs in two branches of physics at one time

    Im a senior in high school and I am interested in pursuing a PHd in physics. I am looking at nuclear physics but I am also considering a,I believe it is called a duel degree, in ether astrophysics, plasma physics, or theoretical physics. IM leaning towards theoretical physics myself. Can this be...
  5. F

    Calculate theoretical static pressure drop in moving fluid

    Hi folks, I have a pressure sensor working with arduino to measure depth. I want to calculate what I should see as a change in pressure if I move the tube horizontally under the surface of the water, keeping the tube opening parallel to the flow. I have calculated the dynamic pressure but...
  6. KSNphysics

    Physics Magnetism - Wire Carrying Current in a Loop

    Homework Statement This is a theoretical question, one I'm not sure about. It just randomly popped into my head. Say there is a jumbled wire, one in a glob shape but not overlapping. (Like a deformed circle, or maybe just a rectangle). Assuming we are in a place called "physics utopia" where...
  7. M

    Use of solid materials as medium for data transfer

    Really odd question for you guys but I'm curious about your input, and apologies if it's a foolish question to ask anyway(I'm a CS student and this came up in a discussion with a classmate of mine). So I know this is a fairly odd thought and not likely practical in any real world scenario, but...
  8. conquest

    I Theoretical problem with an empty seat going faster than light

    Hi everyone, Recently I randomly thought of a thought experiment of something going faster than light, along the lines of a shadow or some other "non-information carrying object". In this case it would be an empty seat. The idea is to take 800 million and one chairs of half a meter breadth...
  9. Conclaude

    Other Seeking Physics Undergrad Thesis Problem

    Hi, I'm an undergraduate, currently enrolled in a degree program for Physics. Part of the requirements of the program is—you guessed it—a thesis. Now, I'm not really good with experimental physics, and aside from that, the university I'm currently enrolled at doesn't really have much equipment...
  10. S

    A Relations between statistical physics and theoretical CS

    Hi everyone. I wasn't sure where to post this thread, so I figured I'll post this under General Physics. Out of interest, I've been perusing online about connections that exist between statistical physics and theoretical computer science. For example, consider the following report by Pietro...
  11. N

    Books for the theoretical minimum video courses

    Hi, everyone. I'm currently taking a gap year, and my plan is to study physics, probably for the rest of my life (With that I mean, reading and learning physics for the rest of my life ;-) ) But I thought why not start now? I kind of have fallen in love with the lectures held by Leonard...
  12. Mikaelochi

    Other Do theoretical physicists use significant figures?

    I know the phrase ''theoretical physicist'' may be a general term, do they or ''mathematical physicists'' use significant figures? I know it's kind of a silly question, but it stems from what I learned in chemistry class. Our chemistry teacher talked about the importance of such things and I...
  13. LevLandau

    Studying Theoretical physics or pure mathematics?

    have a nice day. I was torn between mathematics and physics. I do not know which one I wanted. How can I decide? for me; theoretical physics, applied mathematics - topology (dif.topology, alg.topology, geom.topology), differential geometry easy than pure, proof based mathemics. I'm better...
  14. R

    Other Phenomenology vs theoretical physics -- What should I choose?

    Hi I am an undergraduate student of physics in the university of Athens. I am reaching my final year of studying and we are asked to select and work with one of our professors so that we can make a (barchelors) thesis about a specific specialization. I have know for a long time that I want to...
  15. B

    Theoretical Maximum Velocity Of Electric Jet?

    I'm wondering about theoretical maximum velocities of supersonic electric aircraft. I think the fastest demonstration of any type of aircraft has been close to mach 10. This was done using a rocket engine, so propulsion would not be limited by air characteristics as much as a fan's propulsion...
  16. ramzerimar

    I Laplace's Demon and determinism

    Not sure if this is the correct forum to post this thread, but here we go. I'm a layman in physics and mathematics, and recently, I was reading about the Laplace's Demon and how, according to classical mechanics, the future could be entirely determined if some entity (the Demon) could have...
  17. Liam Lau

    Mathematical Physics or Theoretical Physics

    Hi, I am currently applying to university and am an aspiring Theoretical Physicist. I see many different courses but the two I am not sure on are Mathematical Physics and Theoretical Physics. I was wondering what would give me a better foundation to go on to be a Theoretical Physicist, thank...
  18. P

    Physics Advice for becoming a theoretical physicist

    I am 14 and I have had an uncommon interest in math and science (mostly math). I have recently gotten into the mysteries of quantum physics. What I have heard about theoretical physics is that it requires manipulating data to create equations then find the why's and what's for phenomena. I feel...
  19. ibkev

    Relativity Sleeping Beauties in Theoretical Physics: 26 Surprising Insights

    This book Sleeping Beauties in Theoretical Physics: 26 Surprising Insights sounds pretty cool as something to read for fun. Has anyone looked at it yet? I'm wondering also what level of reader it's been written for? https://www.amazon.com/dp/3319134426/?tag=pfamazon01-20
  20. N

    Other I wanna become a theoretical physicist(questions and doubts)

    I want to become a theoretical physicist and work on string theory and quantum mechanics and stuff like that but I don't know how. Should I go to a high rated school or just the oridinary? I don't need to get paid a lot but I would like to get atleast the average(not sure what that is) but since...
  21. gerardofingurbe

    Going from Electronics Engineering to Theoretical Physics?

    Due to the current situation in Venezuela , i decided on studying Two carreers in two different universities a public one and a private one (In Venezuela public universities are best , But they're usually on strike so they delay your studies often and a lot) , What i really love is physics ...
  22. S

    Schools Grad School: Distance Learning ? Theoretical physics

    I will be graduating with a bachelors degree in physics in the next year. Most of my professors have advised me that if I am considering graduate school (which I am), to just go straight for a PhD instead of stopping at a MA. Unfortunately, my family is currently in a terrible place...
  23. M

    Admissions (UK) Where to apply for theoretical PhD programs in Physics?

    Firstly I'd like to apologise as I know this is a pretty common topic to post questions on! Basically I recently graduated with a first class (72% average) from the University of Southampton (Russell group, but obviously not Oxbridge level) and am planning to spend a year out applying to PhD's...
  24. LazarusLong

    Physics Do I have any chance of becoming a theoretical physicist?

    I am a senior physics student. Since high school I have been mainly self-taught in physics. I’ve hardly had any success in university, with an average score of about 74. The reason partly has to do with my terrible algebra skills, with the vast majority of exams being algebra-oriented. However...
  25. S

    Theoretical and practical force to cut metal

    How much force is needed to cut in half a tough tool steel beam 5 cm wide and 1 cm thick? Theoretically, the cohesion is low. For example, the surface tension of water is 71 mN/m. Some materials are more cohesive. Quicksilver has surface tension of 450 mN/m. Molten gold and copper have over 1...
  26. R

    Why is the Cartesian Product S×T Empty When T is Empty?

    Homework Statement Let S be any set and T = ∅. What can you say about the set S×T? Homework EquationsThe Attempt at a Solution The solution is that S×T=∅. I'm not quite sure why this is though. Is it because there isn't anything in T to give an ordered pair so S×T is empty?
  27. L

    Theoretical Magnetic Propulsion

    I was curious to the effects of a strong electromagnetic field applied to an object at distance. The field must be able to quickly activate and deactivate in order to account for the distance traveled towards the object as to eliminate the force applied to the source of the field by the object...
  28. Patrick Farnworth

    Classical Further reading after Theoretical Minimum

    Hi, I've just finished secondary school and am keen to learn some physics before going on to college. As part of this I've just finished reading 'The Theoretical Minimum' by Leonhard Susskind and George Hrabovsky. The book was a really helpful introduction to classical physics and the maths...
  29. KingCrimson

    Studying How to prepare for Theoretical Physics MSci over a gap year?

    So I will be starting an undergraduate MSci degree in Physics/Theoretical Physics in 2017, for the time being I am on a gap year. What's the best way to mentally prepare for a theoretical physics degree? I am not just talking about being familiar with the topics discussed, but also improving my...
  30. D

    Classical The best physics books to build theoretical knowledge

    Could you name your best picks of books that expand on the high school knowledge. Example is the Goldsteins Classical Mechanics which is a classic. What do you recommend for Electricity and Magnetism, Optics, Relativity and Quantum Mechanics? Also what would be the same criteria for some Math...
  31. M

    Convergence of series (Theoretical Question)

    1. The problem: Ive been all afternoon struggling with this doubt. Its a bit more teoric than the rest of the exercices i did and i just can't seem to get around it so here it goes ...
  32. P

    Physics What is a typical day like for a theoretical researcher?

    Hello everyone, I am a high schooler from a European country with a deep interest in physics. I like studying the subject and reading about it both from a technical and a popular point of view. However, I've been wondering what actual theoretical research - the pen-paper kind, if anything like...
  33. J

    Maximum theoretical power from piezoelectric harvesting

    Hi there... I have an application where I know the vibration frequency/force/acceleration of the source... How can I find the maximum theoretical power output (in mw/watts...) of a tuned piezo where its resonance is the same as the source vibration frequency...
  34. A

    Exploring Enthalpy: Magnesium Reactivity in Hydrochloric Acid Lab Results

    I just conducted a lab in which I am testing varying amounts of magnesium to react with a consistent amount of hydrochloric acid, determining which amount of magnesium produces a reaction whose enthalpy is the closest to the theoretical/ideal enthalpy of this equation. I created 3 conditions...
  35. S

    Maximum Theoretical Angular Accuracy of Planer arrays

    Hello,in this link http://dtic.mil/dtic/tr/fulltext/u2/a028054.pdf a paper „Maximum Theoretical Angular Accuracy of Planer and Linear Arrays of Sensors“ can be found.The accuracies are given in equations 19 (respect to the x axis) and 20 (respect to the y axis).My question is: Shall the angle...
  36. R

    Physics Can a Young Person With No Degree Change Theoretical Physics? What to Do?

    Why if a young person like 21 years old with no degrer made a new discovery in theoretical physics like an equation or a theory will not be accepted by people and no one will believe him ? What he should do before to let people accept his discovery ? Can it be accepted if that person was not...
  37. A

    Theoretical Pipe Flow: Understanding Poiseuille's Law

    Hey guys, I am doing an internship and I have had some thoughts about fluid flow that have come up and I am having trouble fully grasping some concepts due to no one being able to thoroughly explain any answer that they might come up with. So I have a crude understanding of some fluid dynamics...
  38. Mr Proton

    Studying I need a physics mentor (Astrophysics or Theoretical)

    Hello all, I am an aspiring physicist, however I am only in high school, and I live in Idaho, I need an adviser. Someone who can tell me what I need to know, best ways to learn things, and how to get to where I want to be. Any help is appreciated.
  39. IahWay

    Courses Undergrad maths for theoretical physics - QIT

    Hi all I am a second year maths and physics student from Australia. I am hoping to complete a PhD in an interesting area of theoretical physics. At the moment I am interested in particles and quantum information theory. Though it is worth keeping in mind that I am only in second year. I know a...
  40. M

    Courses Straight physics or theoretical physics

    Hi guys! I am currently a first year undergrad (of 3 years) doing physics and in 2 months time need to decide whether or not to continue with my straight physics course or take the theoretical physics pathway I want to do a phd in the more theory based side of physics (particular interests...
  41. R

    Admissions What are the requirements to study theoretical physics?

    I am a high school student (still in grade 11) I want to study theoretical physics in USA or Switzerland but I am from the middle east (Lebanon) and I want to know what I need to be accept in theoretical physics what subjects I need and please tell me the grade for each subject I need example ...
  42. D

    Going into theoretical physics with a screw-up undergrad deg

    Hello every one I am from Hong Kong. I am in my mid-twenties and I have a very bad result in my undergraduate degree in physics and it hinders me a lot in applying for a graduate degree. Theoretical physics (gravitation, quantum field, strings) is the field that I want to do research in for my...
  43. T

    I What is the theoretical basis for Kramer's Law?

    Kramer's Law describes the spectrum of Bremsstrahlung: What is the theoretical basis as to why the spectrum assumes this shape?
  44. JOULEJATT

    Programs What are my options after an M.Sc. in theoretical physics?

    I am an engineering graduate(ME) and want to study physics at masters level. If I get a Masters degree in theoretical physics, can I go for a PhD. in an experimental sub field? Say, I write a thesis in Nuclear & particle physics to get a masters degree, Can I go for experimental Nuclear &...
  45. PabloAMC

    Physics Doing theoretical Physics or Math work as a hobby

    I am a bit new in this forum, so excuse me if you have already talked about it before. I've been reading on this forum about the possiblility of doing scientific research without being paid for it, and according to some posts there were some problems, mainly due to a lack of time and social...
  46. science_rules

    B A Speed of Light Theoretical Question

    Let's say a mother ship is traveling at the speed of light. If you shoot a pod out of the mothership at the speed of light(and that pod is already traveling at the speed of light), then wouldn't that pod be traveling at twice the speed of light? And if you have a second pod speeding away from...
  47. Greg Bernhardt

    Insights Interview with a Theoretical Physicist: Carlo Rovelli - Comments

    Greg Bernhardt submitted a new PF Insights post Interview with a Theoretical Physicist: Carlo Rovelli Continue reading the Original PF Insights Post.
  48. D

    Finding a theoretical magnetic dipole

    I recently completed a lab over magnetism and I need some help on my results. We were asked to find the magnetic dipole moment of small neodymium magnets that were about the size of a dime and around 1/4 inch thick. I found the experimental value using my results. However, I have not been...
  49. Greg Bernhardt

    Insights Interview with a Theoretical Physicist: Garrett Lisi - Comments

    Greg Bernhardt submitted a new PF Insights post Interview with a Theoretical Physicist: Garrett Lisi Continue reading the Original PF Insights Post.
  50. A

    Schools Theoretical physics at Uppsala University

    I have been accepted to the the theoretical physics program at Uppsala University. It ranks around 60-120 in the world for physics and astronomy. I know these rankings aren't the best metric to determine how good a program is, but it gives me an idea. I want to know how good the program is for...
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