Editing Theory (section)

==Scientific==
{{Main|Scientific theory}}
In science, the term "theory" refers to "a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been [[Reproducibility|repeatedly confirmed]] through [[observation]] and experiment."<ref>[http://www.nap.edu/openbook.php?record_id=6024&page=2 National Academy of Sciences], 1999</ref><ref name="AAAS Evolution Resources">{{cite web| url = http://www.aaas.org/news/press_room/evolution/qanda.shtml| title = AAAS Evolution Resources}}</ref> Theories must also meet further requirements, such as the ability to make [[Falsifiability|falsifiable]] predictions with consistent accuracy across a broad area of scientific inquiry, and production of strong evidence in favor of the theory from multiple independent sources ([[consilience]]).

The strength of a scientific theory is related to the diversity of phenomena it can explain, which is measured by its ability to make [[Falsifiability|falsifiable]] [[Prediction#Prediction in science|predictions]] with respect to those phenomena. Theories are improved (or replaced by better theories) as more evidence is gathered, so that accuracy in prediction improves over time; this increased accuracy corresponds to an increase in scientific knowledge. Scientists use theories as a foundation to gain further scientific knowledge, as well as to accomplish goals such as inventing technology or curing diseases.

===Definitions from scientific organizations===
The [[United States National Academy of Sciences]] defines scientific theories as follows:<blockquote>The formal scientific definition of "theory" is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. Many scientific theories are so well established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics) ... One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed.<ref>{{cite book |url=http://www.nap.edu/openbook.php?record_id=11876&page=11 |publisher=National Academy of Sciences |year=2008 |title=Science, Evolution, and Creationism|doi=10.17226/11876 |isbn=978-0-309-10586-6 }}</ref></blockquote>

From the [[American Association for the Advancement of Science]]:
<blockquote>A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. The theory of biological evolution is more than "just a theory." It is as factual an explanation of the universe as the atomic theory of matter or the germ theory of disease. Our understanding of gravity is still a work in progress. But the phenomenon of gravity, like evolution, is an accepted fact.<ref name="AAAS Evolution Resources"/></blockquote>

The term ''theory'' is not appropriate for describing [[Scientific modelling|scientific models]] or untested, but intricate hypotheses.

=== Philosophical views===
The [[logical positivist]]s thought of scientific theories as ''deductive theories''—that a theory's content is based on some [[formal system]] of logic and on basic [[axioms]]. In a deductive theory, any sentence which is a [[logical consequence]] of one or more of the axioms is also a sentence of that theory.<ref name="curry"/> This is called the [[received view of theories]].

In the [[semantic view of theories]], which has largely replaced the received view,<ref>{{cite journal |last1=Suppe |first1=Frederick |year=1998 |title=Understanding Scientific Theories: An Assessment of Developments, 1969–1998 |journal=Philosophy of Science |volume=67 |pages=S102–S115 |url=https://www.princeton.edu/~hhalvors/teaching/phi520_f2012/Suppe_2000.pdf |access-date=14 February 2013 |doi=10.1086/392812|s2cid=37361274 }}</ref><ref>{{cite journal |last1=Halvorson |first1=Hans |year=2012 |title=What Scientific Theories Could Not Be |journal=Philosophy of Science |volume=79 |issue=2 |pages=183–206 |url=https://www.princeton.edu/~hhalvors/teaching/phi520_f2012/halvorson2012.pdf |access-date=14 February 2013 |doi=10.1086/664745|citeseerx=10.1.1.692.8455 |s2cid=37897853 }}</ref> theories are viewed as [[scientific models]]. A model is an abstract and informative representation of reality (a "model of reality"), similar to the way that a map is a graphical model that represents the territory of a city or country. In this approach, theories are a specific category of models that fulfill the necessary criteria. (See [[Scientific theory#Theories as models|Theories as models]] for further discussion.)

===In physics===
In [[physics]] the term ''theory'' is generally used for a mathematical framework—derived from a small set of basic [[postulates]] (usually symmetries, like equality of locations in space or in time, or identity of electrons, etc.)—which is capable of producing experimental predictions for a given category of physical systems. One good example is [[classical electromagnetism]], which encompasses results derived from [[gauge symmetry]] (sometimes called gauge invariance) in a form of a few equations called [[Maxwell's equations]]. The specific mathematical aspects of classical electromagnetic theory are termed "laws of electromagnetism", reflecting the level of consistent and reproducible evidence that supports them. Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to specific situations. Many of these hypotheses are already considered adequately tested, with new ones always in the making and perhaps untested.

=== Regarding the term "theoretical" ===
Certain tests may be infeasible or technically difficult. As a result, theories may make predictions that have not been confirmed or proven incorrect. These predictions may be described informally as "theoretical". They can be tested later, and if they are incorrect, this may lead to revision, invalidation, or rejection of the theory.
<ref>{{cite news|url=http://www.livescience.com/21457-what-is-a-law-in-science-definition-of-scientific-law.html|title=What Is a Law in Science?|access-date=1 January 2017|work=Live Science |first=Alina|last=Bradford|date=25 March 2015}}</ref>