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. V

    Computational and Theoretical Physics

    Hello I am starting university this year in the physics department of Bilkent University. I have been doing some general research and I have noticed that computational methods are becoming more and more important in fields such as condensed matter, quantum mechanics, cosmology, biophysics. It...
  2. H

    Physics Graduate in Computer can be theoretical Physicist?

    Hi friends, I am Harsh kumar from India. I am a computer graduate, with a good sense of district Mathematics. I always want to be an theoretical physicist but i unfortunately ended with computer graduation due to my personal reasons I am physically handicap, never mind that, but as my life leads...
  3. S

    Schools University Degree Choosing Help. (Engineering vs Theoretical)

    I'm leaving high school to choose a degree and I'm having a hard time choosing and I thought I wouldn't loose anything by asking here for opinions and maybe similar experiences. I have mediocre grades overall, though I get very good physics and maths sometimes, others I get average (14/20...
  4. R

    Theoretical Mono Poles, String Theory

    Hi all, Would like to start off by letting you all know i am new to the PF and the reason for joining is due to constant ideas and thoughts flooding my brain to no end, i do not have any physics degree's but i do share an intense interest in Physics. According to a friend of mine the only...
  5. E

    Advice for Master in Theoretical Physics

    Hi there, I am currently trying to decide where to go for my M.Sc. degree. I have to decide between the Intercollegiate Program at London, I was accepted at Queen Mary Univ. London, and the International Centre for Theoretical Physics (ICTP) in Trieste, Italy. My main interests are Quantum...
  6. C

    Calc: Comparing Partitions for Integrability

    Homework Statement comparing two partitions: Let f be defined on the interval [0,2] by f(x)=0, if 0≤x≤1 and f(x)=1 otherwise. Consider two partitions P={0,1,2} and Q={0,1-\epsilon, 1+\epsilon,2}, and calculate the difference of the upper and the lower sum with respect to each partition. By...
  7. R

    Possibility of theoretical topic for undergraduate thesis

    If you wish to skip the back story, skip to the last paragraph. The honors college at my university (Arizona State) requires undergraduates to complete a thesis if they wish to graduate from the honors college. I've been extremely excited about presenting a worthwhile thesis as a physics...
  8. R

    Mastering both and experimental and theoretical physics

    I was wondering can one master both experimental and theoretical physics in one particular field of physics? There are past examples like Enrico Fermi,Richard Feynman etc . I want to have the fun of both. Is it possible?
  9. M

    Physics What to do with Theoretical Physics

    Right, so I intend to do a masters in Mathematics but all the modules I'm going to take are in theoretical physics. I'm going to take a mix of everything from QFT, GR, Fluid Mechanics and Astro, just cause I find it all interesting, but not really specialising in any particular area...
  10. T

    International Scholars in Theoretical Physics

    HI all! By the next summer I will take my Bachelor's degree in Theoretical Physics, although I spent my couple previous weeks in searching for International Scholarships in Theoretical Physics, unfortunately I found only one from PSI (Perimeter Institute in Canada), currently they asked me...
  11. K

    Physics Can someone be a theoretical physicist and still believe in God?

    I am a devout mulim and I love physics so can someone be a theoretical physicist and still be a religious person who believes in God?
  12. R

    Theoretical top speed using multiple gravity assist

    Basicaly wanting to know the maximum velocity achievable if we sent out a craft purely to go as fast as poss using gravity assist + initial escape burn. Obviously a time limit would be needed so let's say 10years of gravity assist manouveres. How fast could we go? Would the gforces involved...
  13. C

    Theoretical particle beam weapon

    This is just for fun so don't take it too seriously... So I've read about particle beam weapons and as far as I understand its simply a concentrated beam of particles ie electrons emitted towards an object. I'm pretty sure I'm missing a big piece here when I say it (it just sound too easy) but...
  14. H

    Theoretical doubt with rolling without slipping

    Hi. I'm taking a look at this problem: And my doubt is with step 2 when he calculates the torque. He just says it is Fd. But...why? F only has a component which effectivly does torque. Thanks
  15. V

    Stress and Failure in Theoretical Physics

    My resident theoretical physicist, who I love dearly, is often very distraught. He describes his days of wracking his brains as painful, unproductive, and, at worst, a tedious backtrack through a bunch of stuff that he got wrong and must redo or unthink. Please help me to understand what he...
  16. A

    Maths Options for Theoretical Physics Path

    I'm about to go into my final(3rd) year of a maths BSc in the UK at Warwick university, and am currently looking at what options I'd like to take given that I'm hoping to go down the path into theoretical physics academia. I currently hold offers for Imperial College's "Quantum Fields and...
  17. E

    Is it Possible to Master String Theory with a Mathematics Background?

    I m first year in theoretical mathematics (graduate study), but I am very interested in theoretical physics, I have some knowledge in physics, general knowledge in mechanics and thermodinamics, electrodynamics, optics, waves, basics in quantum theory, but I am very interested in elementary...
  18. P

    Theoretical Lattice Energy for MgF2

    Homework Statement Calculate the theoretical lattice energy for MgF2 (Born-Landé equation) Ionic radius Mg+2 (coordination number 6) = 86 pm Ionic radius F- (coordination number 3) = 116 pm Madelung constant = 2.408 n = 7 Homework Equations The Attempt at a Solution I'm...
  19. P

    How Does Air Resistance Affect Theoretical vs Actual Projectile Range?

    Homework Statement I need to determine theoretical vs actual range of a projectile; but first I must determine initial velocity. The projectile was launched from 1 meter high, at 0° with respect to the horizontal, so I shot it horizontally. The ball landed at a distance of 2.97 meters. My...
  20. S

    Where can I post my own theoretical papers?

    Hello all, I was just wondering if anyone could give me links to any websites that allow anyone to post their own papers. My apologies if I seem like a 'newbie', as I have not before posted a paper online. Any helpful responses are welcomed, thank you
  21. T

    Programs Theoretical Neuroscience - Which Undergrad Major?

    Hello. I'm currently a junior undergraduate at a liberal arts school. Next year I'm transferring to Columbia's engineering program through a wonderful Combined Plan Program. If anyone knows anything about this, I would love some more information than just what I could find on their website...
  22. Low-Q

    Theoretical highest electric charge?

    What is the theoretical highest electric charge possible for an object wihout breaking it? What about charging a piece of PVC to trillions of volt, or trillions times that, or even more. Is it a limit how high the charge can be? Vidar
  23. W

    How Does Math Point to Various Theories in Physics?

    I look around the internet and there are theories about a lot of different aspects of physics such as various alternative theories on gravitation from GR, M-Theory, Quantum Theory. My question is, if math is used in physics to make sense of the world we see, and a lot of mathematical equations...
  24. R

    Physics How many theoretical physicists are there

    I'm not interested in becoming a theoretical physicist, that would be ridiculous, but I am curious to know how many TP are there, how many PHD degrees are awarded each year, how many applicants are there for a PHD per year and how many applicants are there for a masters in theoretical physicists...
  25. D

    Physics What sorts of theoretical physics careers are there?

    Evening forum, I'd like to pursue a doctoral degree in theoretical physics. What sorts of jobs can one get in this field? Where would I work — strictly at a University, or at a lab, private company, etc? Any information about theoretical physics careers is appreciated. Thanks for your...
  26. Matt atkinson

    Need help Second year theoretical physics modules

    Hello, thank you for taking a look at this thread. Here is my dilemma, I can chose 30 credits from various math and physics courses (each worth 10) for my second year, but I've decided to do maths as the rest of my modules are all physics but there are so many I have no idea what maths modules...
  27. R

    Theoretical spring constant calculation for a tube of pipe

    Homework Statement I require the a means to theoretically calculate the spring constant of a hollow tube. Essentially, I need to find the diameter of the glass pipette which will have a spring constant of 100 Newtons/metre. If someone could point me towards relevant information on...
  28. S

    Courses Should I take more theoretical courses or applied courses?

    Hi. I am a math major that got started late. I started taking prerequisites during my sophomore year (which I'm finishing this year). I'll be taking some courses in algebra and analysis next year. There are some courses that can fulfill my major requirements, but some are theoretical and some...
  29. S

    What Are the Best PhD Programs in High Energy Theoretical Physics?

    Hello everyone, I am a physics master's student in continental europe, and I am starting to look into phd positions in (mostly theoretical) high energy physics. I know this has been discussed quite a few times around here as i browsed a bit around but still, I am wondering which are the best...
  30. M

    Theoretical Math: Proving an injection when it's countably infinite.

    Homework Statement Let f: A --> B be an injection and suppose that the set A is countably infinite; how can I prove that there is an injection from B to A if and only if B is countably infinite? Also, if we would suppose that A is uncountable, can B be countable? Homework Equations...
  31. T

    Theoretical, Experimental, Simulation, and end of story?

    Theoretical, Experimental, Simulation, and... end of story? I know that this question cannot be answered with any absolute authority, but I'd still like to hear some speculation. Can there be a next frontier in the tools of science? Previously, we had experiments and theory. Later...
  32. I

    Schools Mid-tier US gradschools with strong math focussed theoretical physics programs

    Hey all, I'm looking to apply for gradschool in the US at the end of this year and I'm currently struggling to figure something out I was hoping someone here might be able to assist me with. I intend to apply to the top 10-15 schools, but given the cost of applications, for universities...
  33. F

    Physics Preparing for a Career in Theoretical Physics | Ben

    I am still in middle school, just getting inducted in the NJHS and hoping to get into the IB program. I really what to get into a career in Theoretical Physics, is there anything i can do to help make my dreams of becoming a Theoretical Physicist a reality? Anything would help...
  34. K

    Theoretical pH of manufactured product

    Need urgent help with a manufacturing problem. Our company built a product that is testing in spec for propionic acid and ammonia, but out of spec for pH. Desperate for this answer. The total product build is 24166.246 KG. The amount of propionic acid added is 15949.723 KG, which puts...
  35. N

    Courses Theoretical physics Graduate courses - is it all string theory?

    Hi, I was wondering what the scope is these days to do a PhD in theoretical physics, but without delving into string theory? Is the world of theoretical physics still very much dominanated by string theory, or can young physicists go down alternative routes? I seem to remember that some years...
  36. I

    Advises before a first experience of research in theoretical physics

    Hi, I'll be starting next week a 6 months internship, and I'll be working on quantum cosmology, roughly. I have been studying physics for 5 years now, and mostly interested in theoretical things for 4 years (from my first lectures of electromagnetism to conformal field theory), but...
  37. S

    Difficult theoretical problem on basis vectors

    How the hell do you prove that the components of a vector w.r.t. a given basis are unique? I have literally no idea how to begin! It's just that with these theoretical problems there's no straightforward starting point!
  38. N

    Difference Between Theoretical and Mathematical Physics

    Hey everyone If you want the concise version, skip over the bit in italics. First I'll quickly introduce myself. I am an undergraduate student, studying physics. I have been reading these forums for some time now (mostly just re-reading the stickies to be honest). In Australia, the first...
  39. J

    Is knowing a computer language vital for someone pursuing Theoretical Physics?

    Hello! I am currently a sophomore in undergrad, majoring in Physics. I haven't been exposed to any computer languages, such as C++, and I am wondering if it necessary for me to know it? My major's requirement doesn't require it, but many of my physicist friends seem to recommend me take it. So...
  40. MathematicalPhysicist

    Programs PhD in Theoretical Cosmology at damtp cambridge.

    Besides having the best academic record and publications, what else can one do to improve his chances to be accepted to this prestige club? Just a dream... :-(
  41. A

    Physics (theoretical) and mathematics

    Hello! I'm now finishing my final year of high school and preparing for university. I've applied to England to Imperial College, UCL, King's College, Queen Mary and Edinburgh all for a physics w/ theoretical physics or simply theoretical physics Msci in four years and planning to do a PhD...
  42. T

    So I'm not into theoretical physics

    I didn't know how to word it other than that. If astrophysics is all theoretical, then I should have worded it better, but even then I am not interested in cosmology, only in how things work, and I was wondering if this even makes sense. I have thought about it, and all I really know is I have a...
  43. M

    Investigating Orifice Problem: Pipe Head Differences & Theoretical Head

    Orifice problem I've been given a list of quantities Pipe before orifice head = 255mm Diameter = 31.75mm Pipe after orifice head = 230mm Diameter= 20mm Time for 10litres to fill in collection tank 67.09seconds Assuming g= 9.81 and density = 1000 from the experiment difference in...
  44. C

    Are old theoretical texts worth saving?

    I am probably in the same boat as a bunch of people. My father passed away and had a ton of texts. He was a PhD/expert in Heat Transfer, Fluid dynamics and Nuclear Engineering. There are some good theoretical engineering,physics,math books from the 30's 40's and 50's, some of which might...
  45. D

    Physics Would I be able to do theoretical physics?

    About a year and a half ago, I fell in love with mathematics, physics, and our universe. I had dropped out of High School when I was 15 (grade 10) and wasted a year outside of school. During this time I started indulging in marijuana and alcohol. Also, ironically, it was during this year that I...
  46. J

    Maximizing Math for Theoretical Physics: Double-Major or Minor?

    Hey u guys. Say I'm an undergraduate wanting to be a physicist. Not just any physicist, but a theoretical physicist. Say that I'm already planning on taking all of the "Mathematical methods for Physics" courses offered at my university, but now I want more of some math action. Which subjects...
  47. A

    How important is geometry if I want to study theoretical physics

    First, let me apologize for my bad English, it's not my native language. Most areas of math for me aren't really an issue. I'm actually quite good at it. But there's one thing I absolutely despise and also something I'm very bad at: geometry. I was planning on studying theoretical physics...
  48. P

    Is there a theoretical upper bound for density?

    Is there a theoretical upper bound for the density of matter? Given a proton (already almost as dense as a black hole, according to Wikipedia), can you theoretically compress it into any non-zero volume? Has any work been done that shows that matter can or cannot achieve certain levels of...
  49. Z

    Lecture videos of Theoretical physics

    Hi guys , I found a lot of incredibly useful lecture videos provided by the international center for theoretical physics see http://www.ictp.tv/ However there is one problems . They use a technology called EyA to view the lectures.It creates high quality images of the black board every 6 seconds...
  50. P

    How to calculate theoretical initial velocity?

    I can do with just an equation, but if anyone is willing to help: Target is 25.6 m away from canon Initial Velocity = 16 m/s Time = 2.6 s Range = 26.7m No air resistance
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