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. nuuskur

    Can a Graph Have m Times More Edges Than Vertices?

    Homework Statement #1 Does there exist a graph that has m times more edges than vertices? #2 How to calculate the number of possible graphs given the number of vertices and edges? Connected graphs, disconnected graphs. Homework EquationsThe Attempt at a Solution #1We know that a complete graph...
  2. FuturePhysicist

    Fields of Theoretical Physics.

    I'm in high school, thinking about what I want to do in college. I am aiming to get some sort of PhD in Theoretical Physics. I would love to just get one in general theoretical physics, but I am unsure if that is offered. I know that I can go into specific areas such as particle or field...
  3. J

    Physics Where is the best place to work as a Theoretical Physicist?

    Hello. I'm finishing my last year of school and I have wanted to become a Theoretical Physicist at CERN for 2 years, so I want to get a PhD degree. Knowing that people at CERN speak both english and french, I decided to study Physics in Paris (bachelor-french, masters-english), but is it CERN...
  4. R

    Coulomb's law theoretical hypothetical question

    The Scenario: Let's say one could have a lot of cations produced from a gas in a single plane contained in a 1 square foot area (like a fence around sheep). This plane of cations is over another one that is on the ground. So basically two layers of Cations in a tall hollow cube like...
  5. S

    How to check theoretical point of view

    I'm reading Frederic's Paugam "Towards the Mathematics of Quantum Field Theory." I'm also interested in higher structures in mathematics which could have applications in physics. How to check theese theories with the experimental data ? For example the data in LHC. Where can I find experimental...
  6. V

    Self-teaching theoretical physics

    I'm interested to get people's opinions on how plausible this is. My goal is to learn physics to the point that I can read and understand the latest works and potentially even contribute something small. My background: I have a bachelors and masters in computer science from a top-3 school and...
  7. Joshua L

    The Top Undergraduate Math Courses for Physics

    Hey all, I am currently a freshman double majoring in Physics and Math at Purdue University. I have been recently creating a schedule that orders all of the courses I need to take and those that I want to take for the rest of my undergraduate endeavors. I know that it's rather early to do...
  8. Warpspeed13

    RPM Limit on Theoretical motor?

    Ok so I was trying to design a flywheel for a project of mine and an idea occurred to me. Why not use a gas instead of a solid wheel so you didn't haven't worry about it exploding? Could you spin a conductive gas using electromagnets situated around the gas chamber? Whats the maximum speed at...
  9. C

    Medical Physics, Theoretical Physics or Astrophysics?

    Hello there. I am a student doing a MSci at one of the top British universities and top 5 world universities according to QS. I am doing a Natural Sciences Degree and must choose a specialisation in Physics starting next term. Ever since I was a child, my dream has been to study Astrophysics...
  10. dkotschessaa

    PAC learning, Theoretical Comp. Sci and Mathematics

    Per another thread I've decided not to pursue a PhD in mathematics, but rather do a Masters with a Thesis option. So it's time to start finding an area and zooming in. I am interested in complexity theory, and have been watching the whole "Big Data" scene with interest (and ignorance). I...
  11. J

    Programs Which degree for theoretical neuroscience

    Hi! Which degree, which subject is more suitable for those wishing to approach theoretical/computational neuroscience and neural simulation, system biology and related fields like bioinformatics? Physics or Comupter science? (I live in Europe and we don't have major/minor system) Physics...
  12. P

    How does theoretical physics advance?

    I've read about scientists such as Einstein who have advanced the field of physics. When Einstein was working on solving the grand unified theory, what were the obstacles? Was he trying to find patterns that could reveal something? Or did he have sufficient data, but solving certain math...
  13. P

    Best opportunities for research in theoretical physics

    What is the physics branch with better opportunities in theoretical research? For exemple many people say that there are fewer chances to get a PhD in quantum gravity than a PhD in others branches of theoretical physics. Is that true? I think that there are more opportunities in theoretical...
  14. H

    Publishing a theoretical paper

    Hi, I've decided to try to write and publish a paper by the end of my undergraduate degree. I'm planning to get advice from professors at my institution at a later stage in the process - I'd like to approach them when I've narrowed my topic some more and made the focus clearer, and when I've...
  15. Strangelet

    Theoretical Physics or Earth Physics?

    Good Evening to everyone! I'm currently a student of theoretical physics. I have a Bachelor Degree in Physics and I'm from Italy. When you finish your B.D. you can choose to go on with your studies in order to get a Master Degree (other 2 years of study) and here you can choose your curricula...
  16. Kostas Tzim

    Theoretical Physicist: Maths or Physics? (Greece)

    Hey folks, If someone wants to be a theoretical physicist is preferable to follow the mathematics department or the physics? i live in greece (just to know)
  17. P

    Exploring BB as a theoretical physicist or astrophysicist?

    I am curious as to the differences, if one wishes to study the big bang and the origin of the universe, as his/hers primary studies. How would my field of study, and expertise differ coming from a theoretical physics background, compared to (theoretical) astrophysics? Would there be any...
  18. WineRedPsy

    Cosmology or Theoretical Physics?

    I don't really have to look into this just yet but it bothers me. I quite like cosmology and stuff like such. Universal topology and relativity and sum of histories and stuff. Fun! I really would like to study any theoretical physics though, it just strikes my fancy particularly. I figure I'd...
  19. S

    How to study Theoretical Mechanics?

    I know Single variable Calculus and I have a basic understanding of multivariable calculus. I also happen to know basic linear algebra. What are the mathematical pre-requisites needed in order to self-study theoretical mechanics? I'm planning to take this course...
  20. W

    Unranked/low ranked graduate programs in theoretical cosmology/hep-th or astro?

    I'm applying for graduate school but am from a basically unknown state school. My stats can be found here: http://www.physicsgre.com/viewtopic.php?f=21&t=5735. I am looking for a low ranked or unranked theoretical cosmology/hep-th school or a similarly ranked observational astronomy program...
  21. N

    Theoretical vs Experimental Equations?

    Hi. I am calculating the pressure loss through straight pipes and pressure loss through pipe fittings. I need to compare the theoretical value with to the actual experimental values. But the thing is, do I use the Darcy equation for both calculations or are there separate equations to calculate...
  22. S

    Suggestions for books every Theoretical Physicist should have

    Hi, I am just starting my studies in earnest in Physics (woo, Freshman!) and plan on eventually seeking a PhD in theoretical physics. I was wondering if there were any "cannon" works, textbooks that almost every one knows or has studied from at some point, that I should start looking at...
  23. A

    Why Must Acceleration Be Constant for the Equation v² = u² + 2as?

    An object has initial speed u and acceleration a. After traveling a distance s, its final speed is v. Which of the following includes the two conditions necessary for the equation, v^2 = u^2 +2as, to apply? I know the answer is a has constant magnitude and a has constant direction, but I am...
  24. G

    How essential is non-commutative algebra in theoretical physics?

    For next term, I was wondering if I should take a course in non-commutative algebra. As of now, I'm focusing on mathematical physics, specifically on the mathematical side of string theory; mirror symmetry and field theories. I know that commutative algebra as well as algebraic geometry are...
  25. C

    Physics vs Theoretical physics

    Having been a lurker on the site for a few months I decided to make a post concerning my current college situation. I started a theoretical physics course this year, while I am intrigued by the material, the first two years of college would be far more relaxed and I would have more time to...
  26. R

    Finding the theoretical value of the wavelength for a double slit experiment?

    Homework Statement m=maximum h=distance on the screen from the center of the pattern to the mth maximum D=distance from the central bright peak to the slits d=distance between two slits I have m=1 d(mm)=0.25mm D=2000mm h=0.5mm wavelength= 6.25E-5mm Homework Equations So I used...
  27. Brunnun

    Doubts of an aspiring Theoretical Physicist

    I hope I do not extend myself here. I am a Brazilian High School student, graduating this year, that plans to pursue a Physics undergraduate in the United States. Since I started High School I decided on my degree; I love physics and my ultimate dream is to research the depths of the field...
  28. F

    Chemistry Theoretical Yield and Percentage Yield of Organic Molecules

    Homework Statement 1. A student investigated several esters, and made octyl acetate, an ester with the fragrance of oranges. The student used the acid derivative, acetyl chloride (as you saw decanedioyl dichloride used to make 6,10 nylon) and 1-octanol. Using the following information...
  29. D

    Theoretical 100% Light Reflection Room

    If there was a room with all walls that are 100% reflective and a light source. If you were to instantaneously remove that light source, would the room still be lighted? If yes, if an object and the light source were previously present the room, and were to be instantaneously removed, would the...
  30. S

    Need Help finding theoretical and actual acceleration (Atwood)

    So, I have an atwood machine lab. What I have been given is the masses of either end and time it takes the heavier mass to hit the ground from a distance. M1= .2kg M2 = .15kg avg time = 1.12 sec What i think I have to do: To find the actual acceleration I have to use v = vi + at and solve for...
  31. T

    Best Undergrad Program for Graduate Level Theoretical Physics?

    Definitely looking to pursue graduate level theoretical physics in Quantum Mechanics. Which undergrad program would be best? Mathematical Physics, General Physics, or Astrophysics?
  32. B

    One Physics MS semester left - what courses to take?

    Hello all, I've got one more semester before I earn my physics MS, and I have space for one or two extra courses. I am going into oceanography, and I would like to have a strong foundation in math in order to understand the theory I'll encounter as well as possible. Lots of physical...
  33. B

    Theoretical Fluid Mechanics - Ideal Fluid Flow

    Homework Statement Write down the complex potential for a source of strength m located at z=ih and a source of strength m located at z=-ih. Show that the real axis is a streamline in the resulting flow field, and so deduce that the complex potential for the two sources is also the complex...
  34. H

    Theoretical Physics: Investigating the Fundamental Laws of Nature

    Hi, So what exactly does somebody who is involved in "theoretical physics" do at their job? This is not the same thing as somebody who is involved in experimental physics, right? If I understand right, theoretical physics is the stuff we learn in class. It's the theory to explain the phenomena...
  35. B3NR4Y

    Is there a point to being a theoretical physicist?

    When I started undergrad I was speaking with my lab professor, a theoretical physicist, and he asked what I wanted to do when I am done with school. I said I planned on being a theoretical physicist and he told me that about 3/4 of the students in his graduate program at Stanford wanted to be...
  36. Ryan_m_b

    Theoretical limit for data transfer given frequency

    Ages ago I read that the maximum possible bandwidth using radio waves was in the low tbps range. I've had this rattling around in my head ever since and have occasionally tried looking it up to see if it was true. I've not had much luck in that but it did prompt me to start wondering what the...
  37. J

    Changing career to an experimentalist from a Theoretical Physics Major

    Hi everyone, I 'm doing a physics degree in Imperial College london, I have a tendency to do experimental physics research in the future, however, I applied to the theoretical physics course 3 years ago, which means (a year less labs than the experimental physicists, I made this decision because...
  38. C

    Transform 10 to 1000 Points on x^9 to x^2 Polynomial

    In the above title 10 and 1000 are arbitrary numbers I will use them below to signify the concept of a smaller and larger number. I know that n points are described by at most an x^(n-1) polynomial. What I really mean to ask is: Is it possible to take a "smaller" amount of points say 10, go...
  39. L

    Research Fields in Theoretical Physics

    The time I will be asked to take a subject for my graduation project and I'm searching for something in hot fields for modern physics research. Unfortunately I don't know where to look and I was hoping for some help. Any suggestion would be much appreciated. Thank you in advance.
  40. M

    MHB Master Thesis in Theoretical and Applied Mathematics

    Hey! :o What topics for master thesis could someone do at the field theoretical mathematics and what at the field applied mathematics?? At the field Theoretical Mathematics there are the subjects: Basic subjects: Algebra, Introduction to Differentiable Manifolds, Functional Analysis, Complex...
  41. PsychonautQQ

    Theoretical Mechanics: velocity dependent force

    Homework Statement A projectile is launched horizontally. A retarding force acts on the projectile of the form F = -Ae^(cv). Find it's speed as function of time. Homework Equations F = ma The Attempt at a Solution m(dv/dt) = -Ae^(cv) e^(-cv) dv = (-A/m) dt I integrated the...
  42. H

    Electromagnetism and theoretical shape of a photon

    Hello all, I have a few questions and a few thoughts I think I understand that according to einsteins theory of relativity, wavelengths can be perceived differently when traveling at different velocities comparatively to when it was emitted. i.e. if something traveling close to the speed...
  43. P

    Advanced mathematics in theoretical physics

    Hi everyone, Please refer me to a very advanced mathematical physics reference that has applications in theoretical particle physics. I have seen the book Howard Georgi in Lie Algebras in particle physics but want more advanced ones. Any ideas would be very appreciated.Paul
  44. N

    Some funny theoretical tasks, classical physics

    Good morning! I want to show you a few exercises given to me by my Physics teacher as an additional task. I'm aware that for some of you they may seem trivial, but I found it hard to face them because of them being full theoretical, with no actual data given. Mind that I'm only 15 :(. I'd love...
  45. D

    Astrophysics vs Theoretical Physics vs Theoretical Astrophysics

    I'm currently looking into a career in either Astrophysics, Theoretical Physics, or Theoretical Astrophysics. What is the difference between the subject matter in each of these three fields and how would I go about attaining status of Theoretical Astrophysicist? I have found numerous majors...
  46. S

    Aspiring to Theoretical Physics as an Undergraduate

    I am currently enrolled at a US university as an undergrad physics major, and my interest is in theoretical particle physics/quantum mechanics. I am wondering if for the sake of theoretical physics it would be wise to dual-major in mathematics as well at the slight expense of some of the other...
  47. A

    How to Find the Theoretical 0-60 mph Time of a Car?

    Homework Statement A car weighs 2200 lbs, has a peak torque of 750 lb ft at 6500 RPM. Assume a CVT and racing differential keeps the power to all four wheels of the car constant and equal. What is the theoretical 0 to 60 mph time? Homework Equations Fd = \frac{1}{2}m v_f ^2 -...
  48. Coelum

    Open Problems in Theoretical Physics

    Dear PFer's, I just finished reading the first chapter of Lee Smolin's famous "The Trouble with Physics". The first chapter of the book is titled "The Five Great Problems in Theoretical Physics" and is the source of the questions I want to post. I searched PF for similar posts, but I found...
  49. B

    Theoretical Particle Physics Book

    I want a book on particle physics which contains lots of theoretical calculations.All books recommended in my class contain lots of experimental techniques and very little about theory.I like "Introduction to Elementary Particles" by D Griffiths.Is there any book like Griffiths?
  50. Q

    Should I pursue a career in theoretical Particle Physics?

    Hi, I'm new to the forums here, so please forgive me if this is the wrong place to post. I'm currently a junior in high school, and from an early age I was put in all the "gifted" classes. Which kind of put pressure on me to choose a career like physics. Despite all the pressure I always loved...
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