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.
Lately the number of scientists against the big bang theory is increasing for lots of reasons espacially the growing number of hypothetical entities like dark matter, dark energy and inflation which scientists were not able to observe but only to predict by the analysis of backround...
What are the (basic) problems with main stream theories of cosmology ?
i do not want crackpotery, just what the people who work in or around
the field think.
I am unqualified to comment and will not, i hope moderators will keep this thead to the point.
Hello everybody...it,s showtime:redface: :redface: why care for studying and being a serious scientist when you can make millions and fame by saying nonsenses?...heeere..we are our list of "Dumb & Dumber" of modern times...
Bible secret codes:=oh yeah¡¡..yes you don,t need to get a...
Are there string theories based on unidirectional paths or strings?
I ask because the polysigned numbers have some strong unidirectional
qualities.
In a lattice environment loops are the only way to return to a source
point.
These loops are inherently unidirectional...
We've been learning about Darwins Evolution and Natural Selection theories in Class... And what I've wondered was if there were any Anti-Darwinism theories since I've seen some before yet I can't seem to find none online.. Any help will be appreciated thanks:)
How can anyone construct a theory with less than 5 % of the information,
i know that you lot are very cleaver, but AE would be a dwarf to any one
that can get a 100% ansewer from 5% information available.
I'm really interested in philosphy now. Especially Solipsism and this one especially:
Determinism is the philosophical proposition that every event, including human cognition and action, is causally determined by an unbroken chain of prior occurrences. No mysterious miracles or wholly random...
The Gravity Probe B satellite has placed four (over redundant) gyroscopes in low polar Earth orbit to primarily test two predictions of General Relativity.
The first effect being tested is (for the GP-B polar orbit) a N-S geodetic precession, caused by the amount a gyro 'leans' over into the...
ok, so it's a little sexist, but I thought it was clever. Ladies, just substitute boy for girl and he for she..
Physical theories as women
By Simon Dedeo
0. Newtonian gravity is your high-school girlfriend. As your first encounter with physics, she's amazing. You will never forget...
I came across this article, which was published in the February 2004 issue of Physical Review A.
"All quantum observables in a hidden-variables model must commute simultaneously" by James Malley
Abstract: Under a standard set of assumptions for a hidden-variables model for quantum events...
Dear PF,
Could anyone advise me where I can find the following book:
Dynamical symmetry breaking in quantum field theories - Miransky, V.A.
Is itt possible to download from somewhere?
Cheers
George
This post is motivated by some of the discussion on the "Is QM inherently non-local" thread. The goal is to demonstrate that there is a local hidden interpretation possible for any signal local theory. This interpretation will be Bell local, but not Bell realistic.
So, let's say we have a set...
hello its me again
i have an other question. What does the latest physics theoreies say about this:
Do photons have a mass if they are in movement ?
i know that they have no mass if they not in movement.
whats about deBroglie?
Could you please give me an explanation which i do...
Does Bell's Theorem apply to non-local HV theories?
I know that Bell says it doesn't, and he has included logic intended to make separability a requirement. But consider this argument:
What does it mean to say there are hidden variables? Einstein said: "I think that a particle must have...
Here is one I am having trouble following. Can anyone help me through my confusion?
Our setup is a normal Bell test using entangled photons created using spontaneous parametric down conversion (PDC). Such a setup uses 2 BBO crystals oriented a 90 degrees relative to each other. See for...
hello,
i'm amit from israel, and i'd love to be an activated member in your forum.
my first question - are there other theories about the beginning of the univers. except of "the big bang" (not religion)?
thanks,
amit
I believe Einstein said,
1.There are four dimensions to space, the normal three plus time.
2. Speed of light cannot be obtained due to an object traveling at such speeds
gaining mass. The faster it goes, the more mass gained, until it reaches “infinite mass”.
3. Mass and Energy are pretty much...
As things seem a bit slow of late i wonder if anyone would give an over view
of the gravity debate, i know the Higgs is still elusive and the graviton remains
un found, no axions as yet, etc, etc, but what does this mean to string and
loop theories?
I have this odd question. I'm not a physicist, just a computer scientist in training with a broad range of interests. So excuse me if I get something completely wrong.
There seems to be a bunch of theories in physics that basically say that some or all universal "constants" are not in fact...
Waddup guys. To my understanding M-Theory is a theory which 'combines' the five superstring theories and supergravity.Also i understand that matematics is not yet advanced enough to make it work(or so I've been told) I am still not sure how this theory is meant to end up as a theory of...
Heya, I am writing a paper at the moment on aether theories from an historical perspective. I am mostly interested in the mathematical basis of aether theories starting from when Maxwell unified electric and magnetic fields.
What I would like to know is if anybody has any idea where to...
Here I'd like to present theories of professor of physico-chemistry, Ph.D. Najip
Valitov from Russia, who discovered new theories after Einstein. Part of his discoveries are described in his web-page:
[PLAIN]www.bashedu.ru/ValitovNKH.htm[/URL]
In 1972 professor Valitov, who lived in the...
in all the failure theory we compare the stress in the structure to the yield
stress in the uniaxial testing. How this is valid?
for example in a structure the max normal stress is sigma x. and we compare this with the maximum normal stress in a uniaxial tension test.
in vonmises also...
I'm sure you've all heard a lot of them in your time, so share with me some of the most rediculous ones, or ones that amuse you most.
I just stumbled across this little beauty:
http://www.nov55.com/geol.html
The person explains in vaguely how soil formation through the means of breakdown...
Does anyone know of any comprehesive sites featuring ALL of the following: the Keynesian theory, Monetarist theory, and the Rational Expectations theory?
Any ones that compare/contrast them would be excellent.
Thanks again.
http://www.scifiscience.co.uk/index.htm
From Astronuc. This gives a very brief introduction to Relativity, Chaos, and Superstring Theories, and a few other Sci-Fi Science concepts.
This is my (limited) understanding of particle physics: In particle physics gauge symmetries play an important role. To allow for massive gauge bosons this symmetry is broken. The theory of weak interactions can be derived from a local SU(2) symmetry, and quantumchromodynamics from a local SU(3)...
some theorist predicts proton can decay, since the decay of proton does not violate any fundemantal conservation law. My question is, could neutrino decay? How come I have never heard of anyone say neutrino could decay?
I am looking to learn about the major flaws with our current theories and data on climate change, particularly in terms of the ice ages. Any examples of inconsistencies or problems with data, or any other information you could give me would be much appreciated.
Thanks,
Matt.
From John Baez’ page on the experimental basis of Special Relativity, he says that:
and
My question pertains to the remarks in blue: aether theories that are experimentally indistinguishable from SR. Where are these theories published? One member (Yogi) makes reference to the so-called...
I've been attending at high school and I have some ideas about complex numbers. I shared my thoughts with my math teacher. He decided to search. I want to make sure if none have thought them so I need some information about complex numbers. Could you offer me some written sources and the...
well there are many stories of human beings being able to do things that we would only think are in our favorite comic books but let's focus on walking on water. from jesus to the monk of tibet, there are lots of stories about human beings walking on water, so is there any theory as to how this...
I've often read that quantum mechanics and relativity theory are logically incompatible theories, meaning that both theories cannot be true. Can anyone use mathematics to prove that?
Thanks,
King
If a galaxy is 1 billion light year far from us and if for us big bang
did happen 13 billion years ago then when it did happen for that galaxy ?
Pure guess will predict the answer 12 billion years, but what the observer on that galaxy will say about us ? will not he predict that we are...
Greetings , my friends!
Haven't asked that question in public before but for now I thought it might be beneficial to do so since You guys know stuff around here.
What do to if You've came to a some kind of science theory? ...new therorem in maths , law in physics or alike which seems...
check this out
http://www.prisonplanet.tv/audio/091204hilton.htm
and this
http://www.freedomunderground.org/memoryhole/pentagon.php#Main
tell me what you think
Which, if any, of Einsteins models and theories have been replaced by more advanced or precise ones?
The only thing that comes to mind was Einstein's "greatest blunder", the cosmological constant. But hasn't that even found its was back into the equations?
Thanks,
Glenn
hello,
from sometime in past i was in contact of the string theories. But one thing that clicked in my mind that how does the physicst started the idea of the string theories (all of them) like Newton formulated the law of gravitational force after he observed the motion of the moon...
Could someone rephrase in a short and casual manner the famous Millenium Problem of the Clay Math institute ?
http://www.claymath.org/millennium/Yang-Mills_Theory/
Thank you for help !
An interesting observation I made while in chemistry lab was that volatile liquids follow a type of "relativity theory." Imagine temperature (T) as the speed of light (C) in this thought experiment. So, as the heated water approaches T>100 degrees Celsius, the water converts to another state...
Items in a data set or group are divided into pairs with specific relationships between each pair. In this way a degree of order is introduced into the set. I understand this can be done with the entire universe but where do I find out more?? Any suggestions would be helpful.
why can we renormalize some theories but others not?..in fact what wo7uld happen if we apply renormalization group method,or Feynmann,s renormalization program to quatnum gravity (non renormalizable theories).
I also found that
http://arXiv.org/abs/hep-th/9507067 they claim to have...