The word theory has a number of distinct meanings in different fields of knowledge, depending on their methodologies and the context of discussion. For other uses, see Knowledge (disambiguation). ...
Meethodology is defined as the analysis of the principles of methods, rules, and postulates employed by a discipline, the systematic study of methods that are, can be, or have been applied within a discipline or a particular procedure or set of procedures [1]. It should be noted that methodology is...
Debate (North American English) or debating (British English) is a formal method of interactive and position representational argument. ...
In science, a theory is a mathematical or logical explanation, or a testable model of the manner of interaction of a set of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise falsified through empirical observation. It follows from this that for scientists "theory" and "fact" do not necessarily stand in opposition. For example, it is a fact that an apple dropped on earth has been observed to fall towards the center of the planet, and the theories commonly used to describe and explain this behavior are Newton's theory of universal gravitation (see also gravitation), and the theory of general relativity. A magnet levitating above a hightemperature superconductor demonstrates the Meissner effect. ...
Mathematics is commonly defined as the study of patterns of structure, change, and space; more informally, one might say it is the study of figures and numbers. Mathematical knowledge is constantly growing, through research and application, but mathematics itself is not usually considered a natural science. ...
Logic (from ancient Greek λόγος (logos), meaning reason) is the study of arguments. ...
An abstract model (or conceptual model) is a theoretical construct that represents something, with a set of variables and a set of logical and quantitative relationships between them. ...
Natural World (sometimes in the past titled Wildlife On One or Wildlife On Two) is a longrunning BBC television series on natural history. ...
A phenomenon (plural: phenomena) is an observable event, especially something special (literally something that can be seen from the Greek word phainomenon = observable). ...
In the scientific method, an experiment (Latin: ex periri, of (or from) trying) is a set of observations performed in the context of solving a particular problem or question, to retain or falsify a hypothesis or research concerning phenomena. ...
Falsifiability (or refutability or testability) is the logical possibility that an assertion can be shown false by an observation or a physical experiment. ...
In philosophy generally, empiricism is a theory of knowledge emphasizing the role of experience, especially sensory perception, in the formation of ideas, while discounting the notion of innate ideas. ...
This article is about the profession. ...
This article covers the physics of gravitation. ...
Gravity redirects here. ...
For a less technical and generally accessible introduction to the topic, see Introduction to general relativity. ...
In common usage, the word theory is often used to signify a conjecture, an opinion, or a speculation. In this usage, a theory is not necessarily based on facts; in other words, it is not required to be consistent with true descriptions of reality. This usage of theory leads to the common incorrect statements. True descriptions of reality are more reflectively understood as statements which would be true independently of what people think about them. In mathematics, a conjecture is a mathematical statement which appears likely to be true, but has not been formally proven to be true under the rules of mathematical logic. ...
This article does not adequately cite its references or sources. ...
Speculation involves the buying, holding, and selling of stocks, bonds, commodities, currencies, collectibles, real estate, derivatives or any valuable financial instrument to profit from fluctuations in its price as opposed to buying it for use or for income via methods such as dividends or interest. ...
For the trade organisation, see Federation Against Copyright Theft. ...
Time Saving Truth from Falsehood and Envy, FranÃ§ois Lemoyne, 1737 For other uses, see Truth (disambiguation). ...
For other uses, see Reality (disambiguation). ...
Theory of knowledge redirects here: for other uses, see theory of knowledge (disambiguation) According to Plato, knowledge is a subset of that which is both true and believed Epistemology or theory of knowledge is the branch of philosophy that studies the nature, methods, limitations, and validity of knowledge and belief. ...
According to the National Academy of Sciences, Some scientific explanations are so well established that no new evidence is likely to alter them. The explanation becomes a scientific theory. In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature that is supported by many facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena.^{[1]} Wikipedia does not have an article with this exact name. ...
Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Webbased project to create a free content dictionary, available in over 151 languages. ...
Etymology
English attested since 1592, from Greek theoria (Jerome), Greek "contemplation, speculation", from "spectator", thea  "a view" + horan  "to see.", literally "looking at a show".^{[2]} There is a second possible etymology that traces the word back to to theion (divine things) instead of thea, reflecting the concept of contemplating the divine organisation (Cosmos) of the nature. Theoria is contemplation or perception of beauty, esp. ...
The Ancient and Medieval cosmos as depicted in Peter Apians Cosmographia (Antwerp, 1539). ...
Science In scientific usage, a theory does not mean an unsubstantiated guess or hunch, as it can in everyday speech. A theory is a logically selfconsistent model or framework for describing the behavior of a related set of natural or social phenomena. It originates from or is supported by experimental evidence (see scientific method). In this sense, a theory is a systematic and formalized expression of all previous observations, and is predictive, logical, and testable. In principle, scientific theories are always tentative, and subject to corrections or inclusion in a yet wider theory. Commonly, many more specific hypotheses may be logically bound together by just one or two theories. As a rule for use of the term, theories tend to deal with much broader sets of universals than do hypotheses, which ordinarily deal with much more specific sets of phenomena or specific applications of a theory. In Mohr, 2008, the author argues that theory is espoused in a construct without pragmatic relevance when utilized through various sociological or philosophical schools of thought. Truth, in theory, then becomes relativistic depending on its framework. Mohr further argues that as a result of the dilution of what constitutes truth and emerging relativism in the field, that framework evaluation for the creation of theory is now obsolete. An abstract model (or conceptual model) is a theoretical construct that represents something, with a set of variables and a set of logical and quantitative relationships between them. ...
In the scientific method, an experiment (Latin: ex periri, of (or from) trying) is a set of observations performed in the context of solving a particular problem or question, to retain or falsify a hypothesis or research concerning phenomena. ...
Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. ...
Logic (from Classical Greek Î»ÏŒÎ³Î¿Ï‚ logos; meaning word, thought, idea, argument, account, reason, or principle) is the study of the principles and criteria of valid inference and demonstration. ...
A hypothesis (= assumption in ancient Greek) is a proposed explanation for a phenomenon. ...
Thus, as framed by Mohr (2008), it is commonly believed that there are known truths that are superior to theories. If this is actually the case, then the seemingly "known truth" is actually a theory itself. One theory may be superior to another in terms of its approximation of truth, but both statements are theories. Scientific tests of the quality of a theory include its conformity to known facts and its ability to generate hypotheses with outcomes that would predict further testable facts. Facts may refer to: fact, an incontrovertible truth Flexible AC transmission system, abbreviated FACTS Facts (newspaper), a Swiss newspaper Category: ...
A difference in usage of the word "fact" contributes to confusion in regard to the meaning of "theory." An appreciation of the various meanings of "fact" and "knowledge" can help to clarify an understanding of the meanings of "theory." (See also: relativity of knowledge, under Relativism.) For the physics theory with a similar name, see Theory of Relativity. ...
The term theoretical The term theoretical is sometimes informally used in lieu of hypothetical to describe a result which is predicted by theory but has not yet been adequately tested by observation or experiment. It is not uncommon for a theory to produce predictions which are later confirmed or proven incorrect by experiment. By inference, a prediction proved incorrect by experiment demonstrates that the hypothesis is invalid. This either means the theory is incorrect or that the experimental conjecture was wrong and the theory did not predict the hypothesis. Look up Hypothesis in Wiktionary, the free dictionary. ...
For other uses, see Observation (disambiguation). ...
In the scientific method, an experiment (Latin: ex periri, of (or from) trying) is a set of observations performed in the context of solving a particular problem or question, to retain or falsify a hypothesis or research concerning phenomena. ...
In physics In physics the term theory is generally used for a mathematical framework — derived from a small set of basic principles (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. A good example is electromagnetic theory, which encompasses the results which can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today taken for granted. Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to specific situations. Many of these hypotheses are already considered to be adequately tested, with new ones always in the making and perhaps untested as yet. A magnet levitating above a hightemperature superconductor demonstrates the Meissner effect. ...
Maxwells equations are the set of four equations, attributed to James Clerk Maxwell, that describe the behavior of both the electric and magnetic fields, as well as their interactions with matter. ...
Gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ...
Gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ...
For thermodynamic relations, see Maxwell relations. ...
Classical electrodynamics (or classical electromagnetism) is a theory of electromagnetism that was developed over the course of the 19th century, most prominently by James Clerk Maxwell. ...
Currently unverifiable theories The term theory is occasionally stretched to refer to theoretical speculation which is currently unverifiable. Examples are string theory and various theories of everything. Interaction in the subatomic world: world lines of pointlike particles in the Standard Model or a world sheet swept up by closed strings in string theory This box: String theory is a model of fundamental physics, whose building blocks are onedimensional extended objects called strings, rather than the zero...
This page discusses Theories of Everything in physics. ...
Theories as "models" Purpose Theories are constructed in order to explain, predict and master phenomena (e.g. inanimate things, events, or the behaviour of animals). In many instances we are constructing models of reality. A theory makes generalizations about observations and consists of an interrelated, coherent set of ideas and models. An abstract model (or conceptual model) is a theoretical construct that represents something, with a set of variables and a set of logical and quantitative relationships between them. ...
For other uses, see Reality (disambiguation). ...
Description and prediction According to Stephen Hawking in A Brief History of Time, "a theory is a good theory if it satisfies two requirements: It must accurately describe a large class of observations on the basis of a model which contains only a few arbitrary elements, and it must make definite predictions about the results of future observations". He goes on to state, "any physical theory is always provisional, in the sense that it is only a hypothesis; you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation which disagrees with the predictions of the theory". Stephen William Hawking, CH, CBE, FRS, FRSA, (born 8 January 1942) is a British theoretical physicist. ...
A Brief History of Time is a popular science book written by Professor Stephen Hawking and first published in 1988. ...
Assumptions to formulate a theory This is a view shared by Isaac Asimov. In Understanding Physics, Asimov spoke of theories as "arguments" where one deduces a "scheme" or model. Arguments or theories always begin with some premises  "arbitrary elements" as Hawking calls them (see above), which are here described as "assumptions". An assumption according to Asimov is Isaac Asimov (January 2?, 1920?[1] â€“ April 6, 1992), pronounced , originally Ð˜ÑÐ°Ð°Ðº ÐžÐ·Ð¸Ð¼Ð¾Ð² but now transcribed into Russian as ÐÐ¹Ð·ÐµÐº ÐÐ·Ð¸Ð¼Ð¾Ð² [1], was a Russianborn American author and professor of biochemistry, a highly successful writer, best known for his works of science fiction and for his popular science books. ...
something accepted without proof, and it is incorrect to speak of an assumption as either true or false, since there is no way of proving it to be either (If there were, it would no longer be an assumption). It is better to consider assumptions as either useful or useless, depending on whether deductions made from them corresponded to reality. ... On the other hand, it seems obvious that assumptions are the weak points in any argument, as they have to be accepted on faith in a philosophy of science that prides itself on its rationalism. Since we must start somewhere, we must have assumptions, but at least let us have as few assumptions as possible. For other uses, see Philosophy (disambiguation). ...
(See Occam's Razor) For the House television show episode called Occams Razor, see Occams Razor (House episode) Occams razor (sometimes spelled Ockhams razor) is a principle attributed to the 14thcentury English logician and Franciscan friar William of Ockham. ...
Example: Special Theory of Relativity As an example of the use of assumptions to formulate a theory, consider how Albert Einstein put forth his Special Theory of Relativity. He took two phenomena which had been observed — that the "addition of velocities" is valid (Galilean transformation), and that light did not appear to have an "addition of velocities" (MichelsonMorley experiment). He assumed both observations to be correct, and formulated his theory, based on these assumptions, by simply altering the Galilean transformation to accommodate the lack of addition of velocities with regard to the speed of light. The model created in his theory is, therefore, based on the assumption that light maintains a constant velocity (or more precisely: the speed of light is a constant). â€œEinsteinâ€ redirects here. ...
Special relativity (SR) or the special theory of relativity is the physical theory published in 1905 by Albert Einstein. ...
The Galilean transformation is used to transform between the coordinates of two reference frames which differ only by constant relative motion within the constructs of Newtonian physics. ...
The MichelsonMorley experiment, one of the most important and famous experiments in the history of physics, was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University, and is considered by some to be the first strong evidence against the theory of...
Example: Ptolemy An example of how theories are models can be seen from theories on the planetary system. The Greeks formulated theories which were recorded by the astronomer Ptolemy. In Ptolemy's planetary model, the earth was at the center, the planets and the sun made circular orbits around the earth, and the stars were on a sphere outside of the orbits of the planet and the earth. Retrograde motion of the planets was explained by smaller circular orbits of individual planets. This could be illustrated as a model, and could even be built into a literal model. Mathematical calculations could be made which predicted, to a great degree of accuracy, where the planets would be. His model of the planetary system survived for over 1500 years until the time of Copernicus. So one can see that a theory is a "model of reality," one which explains certain scientific facts; yet the theory may not be a satisfactory picture of reality. Another, more acceptable, theory can later replace the previous model, as when the Copernican theory replaced the Ptolemaic theory. Or a new theory can be used to modify an older theory as when Einstein modified Newtonian mechanics (which is still used for designing bridges and gasoline engines) with his theories of relativity. This article is about the geographer, mathematician and astronomer Ptolemy. ...
This article is about retrograde motion. ...
Nicolaus Copernicus (in Latin; Polish Mikołaj Kopernik, German Nikolaus Kopernikus  February 19, 1473 – May 24, 1543) was a Polish astronomer, mathematician and economist who developed a heliocentric (Suncentered) theory of the solar system in a form detailed enough to make it scientifically useful. ...
Differences between theory and model Central to the nature of models, from general models to scale models, is the employment of representation (literally, "representation") to describe particular aspects of a phenomenon or the manner of interaction among a set of phenomena. For instance, a scale model of a house or of a solar system is clearly not an actual house or an actual solar system; the aspects of an actual house or an actual solar system represented in a scale model are, only in certain limited ways, representative of the actual entity. In most ways that matter, the scale model of a house is not a house. Several commentators (e.g., Reese & Overton 1970; Lerner, 1998; Lerner & Teti, 2005, in the context of modeling human behavior) have stated that the important difference between theories and models is that the first is explanatory as well as descriptive, while the second is only descriptive (although still predictive in a more limited sense). General models and theories, according to philosopher Stephen Pepper (1948)  who also distinguishes between theories and models  are predicated on a "root" metaphor which constrains how scientists theorize and model a phenomenon and thus arrive at testable hypotheses. In engineering practice, a distinction is made between "mathematical models" and "physical models".
Characteristics The difference between science and unscientific nonsense was well caught in Wolfgang Pauli's famous comment on a paper he was shown: "This isn't right. It's not even wrong". This article is about the AustrianSwiss physicist. ...
(For the weblog entitled Not Even Wrong, see Peter Woit) A scientific concept is said to be not even wrong if it is not falsifiable in the Popperian sense, or if it is not wellenough formed to be used to make specific predictions about the physical world. ...
Essential criteria The defining characteristic of a scientific theory is that it makes falsifiable or testable predictions about things not yet observed. The relevance, and specificity of those predictions determine how (potentially) useful the theory is. A wouldbe theory which makes no predictions which can be observed is not a useful theory. Predictions which are not sufficiently specific to be tested are similarly not useful. In both cases, the term 'theory' is inapplicable. This page discusses how a theory or assertion is falsifiable (disprovable opp: verifiable), rather than the nonphilosophical use of falsification, meaning counterfeiting. ...
The New York Times reported on Einsteins confirmed prediction. ...
In practice a body of descriptions of knowledge is usually only called a theory once it has a minimum empirical basis. That is, it: For other uses, see Knowledge (disambiguation). ...
 is consistent with preexisting theory to the extent that the preexisting theory was experimentally verified, though it will often show preexisting theory to be wrong in an exact sense, and
 is supported by many strands of evidence rather than a single foundation, ensuring that it is probably a good approximation, if not totally correct.
Nonessential criteria Additionally, a theory is generally only taken seriously if it:  is tentative, correctable and dynamic, in allowing for changes to be made as new data are discovered, rather than asserting certainty, and
 is the most parsimonious explanation, sparing in proposed entities or explanations, commonly referred to as passing the Occam's razor test.
This is true of such established theories as special and general relativity, quantum mechanics, plate tectonics, evolution, etc. Theories considered scientific meet at least most, but ideally all, of these extra criteria. Look up parsimony in Wiktionary, the free dictionary. ...
For the House television show episode called Occams Razor, see Occams Razor (House episode) Occams razor (sometimes spelled Ockhams razor) is a principle attributed to the 14thcentury English logician and Franciscan friar William of Ockham. ...
For a less technical and generally accessible introduction to the topic, see Introduction to special relativity. ...
For a less technical and generally accessible introduction to the topic, see Introduction to general relativity. ...
For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ...
The tectonic plates of the world were mapped in the second half of the 20th century. ...
This article is about evolution in biology. ...
Theories do not have to be perfectly accurate to be scientifically useful. The predictions made by Classical mechanics are known to be inaccurate, but they are sufficiently good approximations in most circumstances that they are still very useful and widely used in place of more accurate but mathematically difficult theories. Classical mechanics (commonly confused with Newtonian mechanics, which is a subfield thereof) is used for describing the motion of macroscopic objects, from projectiles to parts of machinery, as well as astronomical objects, such as spacecraft, planets, stars, and galaxies. ...
Indistinguishable theories Sometimes it happens that two theories are found to make exactly the same predictions. In this case, they are indistinguishable, and the choice between them reduces to which is the more convenient.
Criterion for scientific status Karl Popper described the characteristics of a scientific theory as follows: Sir Karl Raimund Popper CH FRS FBA (July 28, 1902 â€“ September 17, 1994) was an Austrian and British[1] philosopher and a professor at the London School of Economics. ...
 It is easy to obtain confirmations, or verifications, for nearly every theory — if we look for confirmations.
 Confirmations should count only if they are the result of risky predictions; that is to say, if, unenlightened by the theory in question, we should have expected an event which was incompatible with the theory — an event which would have refuted the theory.
 Every "good" scientific theory is a prohibition: it forbids certain things to happen. The more a theory forbids, the better it is.
 A theory which is not refutable by any conceivable event is nonscientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.
 Every genuine test of a theory is an attempt to falsify it, or to refute it. Testability is falsifiability; but there are degrees of testability: some theories are more testable, more exposed to refutation, than others; they take, as it were, greater risks.
 Confirming evidence should not count except when it is the result of a genuine test of the theory; and this means that it can be presented as a serious but unsuccessful attempt to falsify the theory. (I now speak in such cases of "corroborating evidence.")
 Some genuinely testable theories, when found to be false, are still upheld by their admirers — for example by introducing ad hoc some auxiliary assumption, or by reinterpreting the theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least lowering, its scientific status. (I later describe such a rescuing operation as a "conventionalist twist" or a "conventionalist stratagem").
One can sum up all this by saying that according to Popper, the criterion of the scientific status of a theory is its falsifiability, or refutability, or testability. Several philosophers and historians of science have, however, argued that Popper's definition of theory as a set of falsifiable statements is wrong ^{[3]} because, as Philip Kircher has pointed out, if one took a strictly Popperian view of “theory,” observations of Uranus when first discovered in 1781 would have “falsified” Newton’s celestial mechanics. Rather, people suggested that another planet influenced Uranus’ orbit – and this prediction was indeed eventually confirmed. Kitcher agrees with Popper that “there is surely something right in the idea that a science can succeed only if it can fail” ^{[4]}. He also takes into account Hempel and Quine’s critiques of Popper, to the effect that scientific theories include statements that cannot be falsified (presumably what Hawking alluded to as arbitrary elements), and the point that good theories must also be creative. He insists that we view scientific theories as consisting of an “elaborate collection of statements,” some of which are not falsifiable, while others – those he calls “auxiliary hypotheses,” are. According to Kitcher, good scientific theories must have three features:  Unity: “A science should be unified …. Good theories consist of just one problemsolving strategy, or a small family of problemsolving strategies, that can be applied to a wide range of problems” (1982: 47).
 Fecundity: “A great scientific theory, like Newton’s, opens up new areas of research. …. Because a theory presents a new way of looking at the world, it can lead us to ask new questions, and so to embark on new and fruitful lines of inquiry …. Typically, a flourishing science is incomplete. At any time, it raised more questions than it can currently answer. But incompleteness is now vice. On the contrary, incompleteness is the mother of fecundity …. A good theory should be productive; it should raise new questions and presume that those questions can be answered without giving up its problemsolving strategies” (1982: 4748).
 Auxiliary hypotheses that are independently testable: “An auxiliary hypothesis ought to be testable independently of the particular problem it is introduced to solve, independently of the theory it is designed to save” (1982: 46) (e.g. the evidence for the existence of Neptune is independent of the anomalies in Uranus’s orbit).
Like other definitions of theories, including Popper’s, Kitcher makes it clear that a good theory includes statements that have (in his terms) “observational consequences.” But, like the observation of irregularities in the orbit of Uranus, falsification is only one possible consequence of observation. The production of new hypotheses is another possible – and equally important – observational consequence.
Mathematics In mathematics, the word theory is used informally to refer to certain distinct bodies of knowledge about mathematics. This knowledge consists of axioms, definitions, theorems and computational techniques, all related in some way by tradition or practice. Examples include group theory, set theory, Lebesgue integration theory and field theory. For other meanings of mathematics or uses of math and maths, see Mathematics (disambiguation) and Math (disambiguation). ...
Group theory is that branch of mathematics concerned with the study of groups. ...
Set theory is the mathematical theory of sets, which represent collections of abstract objects. ...
The integral of a positive function can be interpreted as the area under a curve. ...
Field theory is a branch of mathematics which studies the properties of fields. ...
The term theory also has a precise technical usage in mathematics, particularly in mathematical logic and model theory. A theory in this sense is a set of statements in a formal language, which is closed under application of certain procedures called rules of inference. A special case of this, an axiomatic theory, consists of axioms (or axiom schemata) and rules of inference. A theorem is a statement which can be derived from those axioms by application of these rules of inference. Theories used in applications are abstractions of observed phenomena and the resulting theorems provide solutions to realworld problems. Obvious examples include arithmetic (abstracting concepts of number), geometry (concepts of space), and probability (concepts of randomness and likelihood). In mathematical logic, a theory is usually defined as a set of firstorder sentences (closed firstorder formulas). ...
Mathematical logic is a major area of mathematics, which grew out of symbolic logic. ...
In mathematics, model theory is the study of the representation of mathematical concepts in terms of set theory, or the study of the structures that underlie mathematical systems. ...
In mathematics, logic, and computer science, a formal language is a language that is defined by precise mathematical or machine processable formulas. ...
In mathematics, a set is said to be closed under some operation if the operation on members of the set produces a member of the set. ...
In logic, especially in mathematical logic, a rule of inference is a scheme for constructing valid inferences. ...
For the algebra software named Axiom, see Axiom computer algebra system. ...
Look up theorem in Wiktionary, the free dictionary. ...
This article is about the concept of abstraction in general. ...
Arithmetic tables for children, Lausanne, 1835 Arithmetic or arithmetics (from the Greek word Î±ÏÎ¹Î¸Î¼ÏŒÏ‚ = number) is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple daytoday counting to advanced science and business calculations. ...
For other uses, see Geometry (disambiguation). ...
Probability is the likelihood that something is the case or will happen. ...
Gödel's incompleteness theorem shows that no consistent, recursively enumerable theory (that is, one whose theorems form a recursively enumerable set) in which the concept of natural numbers can be expressed, can include all true statements about them. As a result, some domains of knowledge cannot be formalized, accurately and completely, as mathematical theories. (Here, formalizing accurately and completely means that all true propositions – and only true propositions – are derivable within the mathematical system.) This limitation, however, in no way precludes the construction of mathematical theories which formalize large bodies of scientific knowledge. In mathematical logic, GÃ¶dels incompleteness theorems are two celebrated theorems proven by Kurt GÃ¶del in 1931. ...
Look up Consistency in Wiktionary, the free dictionary. ...
In computability theory, often less suggestively called recursion theory, a countable set S is called recursively enumerable, computably enumerable, semidecidable or provable if There is an algorithm that, when given an input — typically an integer or a tuple of integers or a sequence of characters — eventually halts if it...
Natural number can mean either a positive integer (1, 2, 3, 4, ...) or a nonnegative integer (0, 1, 2, 3, 4, ...). Natural numbers have two main purposes: they can be used for counting (there are 3 apples on the table), or they can be used for ordering (this is...
Time Saving Truth from Falsehood and Envy, FranÃ§ois Lemoyne, 1737 For other uses, see Truth (disambiguation). ...
Other fields Theories exist not only in the socalled hard sciences, but in all fields of academic study, from philosophy to music to literature. The Michelsonâ€“Morley experiment was used to disprove that light propagated through a luminiferous aether. ...
In the humanities, theory is often used as an abbreviation for critical theory or literary theory. For other uses, see Humanities (disambiguation). ...
In the humanities and social sciences, critical theory has two quite different meanings with different origins and histories, one originating in social theory and the other in literary criticism. ...
Literary theory is the theory (or the philosophy) of the interpretation of literature and literary criticism. ...
List of notable theories Find more about Theory on Wikipedia's sister projects: 
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 Learning resources  Wikipedia does not have an article with this exact name. ...
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For other uses, see Astronomy (disambiguation). ...
According to the Big Bang theory, the universe originated in an infinitely dense and physically paradoxical singularity. ...
For the song by Girls Aloud see Biology (song) Biology studies the variety of life (clockwise from topleft) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: Î²Î¯Î¿Ï‚, bio, life; and Î»ÏŒÎ³Î¿Ï‚, logos, speech lit. ...
A prokaryote, a simple cell Cell theory refers to the idea that cells are the basic unit of structure in all living things. ...
This article is about evolution in biology. ...
For other uses, see Chemistry (disambiguation). ...
This article focuses on the historical models of the atom. ...
Kinetic theory or kinetic theory of gases attempts to explain macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion. ...
Climatology is the study of climate, scientifically defined as weather conditions averaged over a period of time,[1] and is a branch of the atmospheric sciences. ...
Global warming refers to the increase in the average temperature of the Earths nearsurface air and oceans in recent decades and its projected continuation. ...
Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ...
This article or section is in need of attention from an expert on the subject. ...
Look up computation in Wiktionary, the free dictionary. ...
Facetoface trading interactions on the New York Stock Exchange trading floor. ...
Decision theory is an area of study of discrete mathematics that models human decisionmaking in science, engineering and indeed all human social activities. ...
It has been suggested that this article or section be merged with Constructionist learning. ...
Critical pedagogy is a teaching approach which attempts to help students question and challenge domination, and the beliefs and practices that dominate. ...
Education theory is the theory or the philosophy of the purpose, application and interpretation of education and learning. ...
Multiple intelligences is a psychological and educational theory put forth by psychologist Howard Gardner, which suggests that an array of different kinds of intelligence exists in human beings. ...
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Engineering is the discipline of acquiring and applying knowledge of design, analysis, and/or construction of works for practical purposes. ...
An electrical network or electrical circuit is an interconnection of analog electrical elements such as resistors, inductors, capacitors, diodes, switches and transistors. ...
For control theory in psychology and sociology, see control theory (sociology). ...
Signal theory is the theory of the engineering discipline of signal processing. ...
Systems theory is an interdisciplinary field of science. ...
This article is about motion pictures. ...
Film theory debates the essence of the cinema and provides conceptual frameworks for analyzing, among other things, the film image, narrative structure, the function of film artists, the relationship of film to reality, and the film spectators position in the cinematic experience. ...
For other uses, see Game (disambiguation). ...
Game theory is a branch of applied mathematics that is often used in the context of economics. ...
Rational choice theory assumes human behavior is guided by instrumental reason. ...
This article includes a list of works cited but its sources remain unclear because it lacks intext citations. ...
The tectonic plates of the world were mapped in the second half of the 20th century. ...
For other uses, see Humanities (disambiguation). ...
In the humanities and social sciences, critical theory has two quite different meanings with different origins and histories, one originating in social theory and the other in literary criticism. ...
For other uses, see Literature (disambiguation). ...
Literary theory is the theory (or the philosophy) of the interpretation of literature and literary criticism. ...
For other meanings of mathematics or uses of math and maths, see Mathematics (disambiguation) and Math (disambiguation). ...
In mathematics, catastrophe theory is a branch of bifurcation theory in the study of dynamical systems; it is also a particular special case of more general singularity theory in geometry. ...
In mathematics, category theory deals in an abstract way with mathematical structures and relationships between them. ...
For other uses, see Chaos Theory (disambiguation). ...
A drawing of a graph. ...
Trefoil knot, the simplest nontrivial knot. ...
Number theory is the branch of pure mathematics concerned with the properties of numbers in general, and integers in particular, as well as the wider classes of problems that arise from their study. ...
Probability theory is the branch of mathematics concerned with analysis of random phenomena. ...
Set theory is the mathematical theory of sets, which represent collections of abstract objects. ...
For other uses, see Music (disambiguation). ...
Music theory is a field of study that investigates the nature or mechanics of music. ...
For other uses, see Philosophy (disambiguation). ...
Proof theory is a branch of mathematical logic that represents proofs as formal mathematical objects, facilitating their analysis by mathematical techniques. ...
Speculative reason is theoretical (or logical, deductive) thought (sometimes called theoretical reason), as opposed to practical (active, willing) thought. ...
Time Saving Truth from Falsehood and Envy, FranÃ§ois Lemoyne, 1737 For other uses, see Truth (disambiguation). ...
At the broadest level, type theory is the branch of mathematics and logic that first creates a hierarchy of types, then assigns each mathematical (and possibly other) entity to a type. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Virtue (Greek Î±ÏÎµÏ„Î·; Latin virtus) is the habitual, wellestablished, readiness or disposition of mans powers directing them to some goodness of act. ...
A magnet levitating above a hightemperature superconductor demonstrates the Meissner effect. ...
Acoustic theory is the field relating to mathematical description of sound waves. ...
A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ...
For a less technical and generally accessible introduction to the topic, see Introduction to general relativity. ...
For a less technical and generally accessible introduction to the topic, see Introduction to special relativity. ...
Twodimensional analogy of spacetime curvature described in General Relativity. ...
Quantum field theory (QFT) is the quantum theory of fields. ...
Planetary science, also known as planetology or planetary astronomy, is the science of planets, or planetary systems, and the solar system. ...
The Big Splash The giant impact theory (or Big Splash or Big Whack; cf. ...
Many times, the term art is used to refer to the visual arts. ...
Aesthetics (also spelled esthetics) is a branch of philosophy, a species of value theory or axiology, which is the study of sensory or sensoriemotional values, sometimes called judgments of sentiment and taste. ...
Art education is the area of learning that is based upon the visual, tangible artsâ€”drawing, painting, sculpture, and design in jewelry, pottery, weaving, fabrics, etc and design applied to more practical fields such as commercial graphics and home furnishings. ...
This article is about building architecture. ...
Composition is the plan, placement or arrangement of the elements of art in a work. ...
Human heart and lungs, from an older edition of Grays Anatomy. ...
In the arts of painting, and photography, color theory is a set of basic rules for mixing color to achieve a desired result. ...
A cube in twopoint perspective. ...
In psychology, visual perception is the ability to interpret visible light information reaching the eyes which is then made available for planning and action. ...
For other uses, see Geometry (disambiguation). ...
On a sphere, the sum of the angles of a triangle is not equal to 180Â° (see spherical trigonometry). ...
Sociology (from Latin: socius, companion; and the suffix ology, the study of, from Greek Î»ÏŒÎ³Î¿Ï‚, lÃ³gos, knowledge [1]) is the systematic and scientific study of society, including patterns of social relationships, social action, and culture[2]. Areas studied in sociology can range from the analysis of brief contacts between anonymous...
Sociological theory can refer to: contemporary sociological theory social theory sociological paradigms (also known as perespectives or frameworks) See also list of theories in sociology. ...
Social theory refers to the use of abstract and often complex theoretical frameworks to explain and analyze social patterns and largescale social structures. ...
Critical theory, in sociology and philosophy, is shorthand for critical theory of society or critical social theory, a label used by the Frankfurt School, i. ...
This article is about the field of statistics. ...
Extreme value theory is a branch of statistics dealing with the extreme deviations from the median of probability distributions. ...
Serge Sudeikins poster for the Bat Theatre (1922). ...
An obsolete scientific theory is a scientific theory that was once commonly accepted but (for whatever reason) is no longer considered the most complete description of reality by mainstream science; or a falsifiable theory which has been shown to be false. ...
Phlogiston theory was a 17th century attempt to explain oxidation processes, such as fire and rust. ...
Scientific laws 
Main article: Scientific law Scientific laws are similar to scientific theories in that they are principles which can be used to predict the behavior of the natural world. Both scientific laws and scientific theories are typically wellsupported by observations and/or experimental evidence. Usually scientific laws refer to rules for how nature will behave under certain conditions.^{[6]} Scientific theories are more overarching explanations of how nature works and why it exhibits certain characteristics. A scientific law, is a lawlike statement that generalizes across a set of conditions. ...
Notes  ^ National Academy of Sciences (2005), Science, Evolution, and Creationism, a brochure on the book of the same title.
 ^ Frisk; derivation from ?e?? was suggested by Koller Glotta 36, 273ff.
 ^ Hempel. C.G. 1951 “Problems and Changes in the Empiricist Criterion of Meaning” in Aspects of Scientific Explanation. Glencoe: the Free Press. Quine, W.V.O 1952 “Two Dogmas of Empiricism” reprinted in From a Logical Point of View. Cambridge: Harvard University Press
 ^ Philip Kutcher 1982 Abusing Science: The Case Against Creationism. Page 45 Cambridge: The MIT Press
 ^ The theory of plate tectonics is also called the theory of continental drift.
 ^ See the article on Physical law, for example.
President Harding and the National Academy of Sciences at the White House, Washington, DC, April 1921 The National Academy of Sciences (NAS) is a corporation in the United States whose members serve pro bono as advisers to the nation on science, engineering, and medicine. ...
Theos may refer to: Theos () is the Greek word for deity, god; see god (word), names of God. ...
Plates in the crust of the earth, according to the plate tectonics theory Continental drift refers to the movement of the Earths continents relative to each other. ...
For a list of set rules, see Laws of science. ...
References  Popper, Karl (1963), Conjectures and Refutations, Routledge and Kegan Paul, London, UK, pp. 33–39. Reprinted in Theodore Schick (ed., 2000), Readings in the Philosophy of Science, Mayfield Publishing Company, Mountain View, CA, pp. 9–13.
 Chairman of Biology and Kennesaw State Ronald Matson's webpage comparing scientific laws and theories
 Hawking, Stephen (1996). "The Illustrated A Brief History of Time" (Updated and expanded ed.). New York: Bantam Books, p. 15.
 Mohr, Johnathon (2008). "Revelations and Implications of the Failure of Pragmatism: The Hijacking of Knowledge Creation by the Ivory Tower". New York: Ballantine Books. pp. 87192.
Sir Karl Raimund Popper CH FRS FBA (July 28, 1902 â€“ September 17, 1994) was an Austrian and British[1] philosopher and a professor at the London School of Economics. ...
Theodore Schick is an author in the field of philosophy. ...
// Onomastics and disambiguational information about the words, place & humannames that forms Mohr, MÃ¶hr, Moehr, MÃ¶hre, Moehre, etc. ...
See also This is a list of topics commonly referred to as ___ theory. This is not a list of theorems or theories (e. ...
Falsifiability (or refutability or testability) is the logical possibility that an assertion can be shown false by an observation or a physical experiment. ...
In mathematics, logic, and computer science, a formal language is a language that is defined by precise mathematical or machine processable formulas. ...
In logic and mathematics, a formal system consists of two components, a formal language plus a set of inference rules or transformation rules. ...
Look up Hypothesis in Wiktionary, the free dictionary. ...
One may be faced with the problem of making a definite decision with respect to an uncertain hypothesis which is known only through its observable consequences. ...
An abstract model (or conceptual model) is a theoretical construct that represents something, with a set of variables and a set of logical and quantitative relationships between them. ...
The New York Times reported on Einsteins confirmed prediction. ...
Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. ...
Testability, a property applying to an empirical hypothesis, involves two components: (1) the logical property that is variously described as contingency, defeasibility, or falsifiability, which means that counterexamples to the hypothesis are logically possible, and (2) the practical feasibility of observing a reproducible series of such counterexamples if they do...
