Beyond the Standard Model

Standard Model

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A theory of everything (TOE) is a hypothetical theory of theoretical physics that fully explains and links together all known physical phenomena. In Physics, the Standard Model of Particle physics is currently the best description of all experimental data The Standard Model of Particle physics is a theory that describes three of the four known Fundamental interactions together with the Elementary particles The word theory has many distinct meanings in different fields of Knowledge, depending on their methodologies and the context of discussion. Theoretical physics employs Mathematical models and Abstractions of Physics in an attempt to explain experimental data taken of the natural world Initially, the term was used with an ironic connotation to refer to various overgeneralized theories. For example, a great-grandfather of Ijon Tichy — a character from a cycle of Stanisław Lem's science fiction stories of 1960s — was known to work on the "General Theory of Everything". Ijon Tichy is a Fictional character who appears in several works of Stanisław Lem, including The Futurological Congress, Peace Stanisław Lem ( sta'ɲiswaf lɛm 12 September 1921 – 27 March 2006 was a Polish Science fiction, philosophical and satirical writer Physicist John Ellis claims ^[1] to have introduced the term into the technical literature in an article in Nature in 1986 ^[2]. John Ellis is a British theoretical physicist born in 1946 in London Nature is a prominent Scientific journal, first published on 4 November 1869 Over time, the term stuck in popularizations of quantum physics to describe a theory that would unify or explain through a single model the theories of all fundamental interactions of nature. Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons In Physics, a fundamental interaction or fundamental force is a mechanism by which particles interact with each other and which cannot be explained in terms

There have been many theories of everything proposed by theoretical physicists over the last century, but none have been confirmed experimentally. The primary problem in producing a TOE is that the accepted theories of quantum mechanics and general relativity are hard to combine. Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916

Based on theoretical holographic principle arguments from the 1990s, many physicists believe that 11-dimensional M-theory, which is described in many sectors by matrix string theory, in many other sectors by perturbative string theory is the complete theory of everything. The holographic principle is a physical property of Quantum gravity theories proposed by Gerard 't Hooft and Leonard Susskind, which resolves the In Theoretical physics, M-theory is a new limit of String theory in which 11 dimensions of Spacetime may be identified In Physics, matrix string theory is the first known set of equations that describe Superstring theory in a non-perturbatively complete and consistent framework A dual resonance model is a term used in Theoretical physics which refers to the early investigation (1968-1974 on Strong interactions of string theory Other physicists disagree.

Contents 1 Historical antecedents 1.1 Ancient Greece to Einstein 1.2 New discoveries 2 Modern physics 3 With reference to Gödel's incompleteness theorem 4 Potential status of a theory of everything 5 Theory of everything and philosophy 6 See also 7 References 8 Further reading 9 External links

Historical antecedents

Laplace famously suggested that a sufficiently powerful intellect could, if it knew the velocity of every particle at a given time, along with the laws of nature, calculate the position of any particle at any other time:

An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.

– Essai philosophique sur les probabilités, Introduction. 1814

Although modern quantum mechanics suggests that uncertainty is inescapable, a "single formula" may nevertheless exist. Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons

Ancient Greece to Einstein

Since ancient Greek times, philosophers have speculated that the apparent diversity of appearances conceals an underlying unity, and thus that the list of forces might be short, indeed might contain only a single entry. The Ancient Greek language is the historical stage in the development of the Hellenic language family spanning the Archaic (c The Pre-Socratic Greek philosophers were active before Socrates or contemporaneously but expounding knowledge developed earlier For example, the mechanical philosophy of the 17th century posited that all forces could be ultimately reduced to contact forces between tiny solid particles. In Philosophy, mechanism is a Theory that all natural phenomena can be explained by physical causes In Physics, a contact force is a force between two objects (or an object and a surface that are in contact with each other ^[3] This was abandoned after the acceptance of Isaac Newton's long-distance force of gravity; but at the same time, Newton's work in his Principia provided the first dramatic empirical evidence for the unification of apparently distinct forces: Galileo's work on terrestrial gravity, Kepler's laws of planetary motion, and the phenomonenon of tides were all quantitatively explained by a single law of universal gravitation. Sir Isaac Newton, FRS (ˈnjuːtən 4 January 1643 31 March 1727) Biography Early years See also Isaac Newton's early life and achievements The Philosophiæ Naturalis Principia Mathematica ( Latin: "mathematical principles of natural philosophy" often Principia Galileo Galilei (15 February 1564 &ndash 8 January 1642 was a Tuscan ( Italian) Physicist, Mathematician, Astronomer, and Philosopher Johannes Kepler (ˈkɛplɚ ( December 27 1571 &ndash November 15 1630) was a German Mathematician, Astronomer Characteristics A tide is a repeated cycle of sea level changes in the following stages Over several hours the water rises or advances up a beach in the flood Newton 's law of universal Gravitation is a physical law describing the gravitational attraction between bodies with mass

In 1820, Hans Christian Oersted discovered a connection between electricity and magnetism, triggering decades of work that culminated in James Clerk Maxwell's theory of electromagnetism. James Clerk Maxwell (13 June 1831 &ndash 5 November 1879 was a Scottish mathematician and theoretical physicist. Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of Also during the 19th and early 20th centuries, it gradually became apparent that many common examples of forces—contact forces, elasticity, viscosity, friction, pressure—resulted from electrical interactions between the smallest particles of matter. A material is said to be elastic if it deforms under stress (e Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface In the late 1920s, the new quantum mechanics showed that the chemical bonds between atoms were examples of (quantum) electrical forces, justifying Dirac's boast that "the underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known". Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons A chemical bond is the physical process responsible for the attractive interactions between Atoms and Molecules and which confers stability to diatomic and polyatomic History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny ^[4]

Attempts to unify gravity with electromagnetism date back at least to Michael Faraday's experiments of 1849–50. Gravitation is a natural Phenomenon by which objects with Mass attract one another Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of Michael Faraday, FRS ( September 22 1791 – August 25 1867) was an English ^[5] After Albert Einstein's theory of gravity (general relativity) was published in 1915, the search for a unified field theory combining gravity with electromagnetism began in earnest. Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916 In Physics, a unified field theory is a type of Field theory that allows all of the Fundamental forces between Elementary particles to be written At the time, it seemed plausible that no other fundamental forces exist. Prominent contributors were Gunnar Nordstrom, Hermann Weyl, Arthur Eddington, Theodor Kaluza, Oskar Klein, and most notably, many attempts by Einstein and his collaborators. Gunnar Nordström ( 12 March 1881, Helsinki &ndash 24 December 1923, Helsinki was a Finnish theoretical physicist Hermann Klaus Hugo Weyl ( 9 November 1885 – 8 December 1955) was a German Mathematician. Sir Arthur Stanley Eddington, OM (28 December 1882 – 22 November 1944 was an English Astrophysicist of the early 20th century Theodor Franz Eduard Kaluza ( November 9, 1885 &ndash January 19, 1954) was a German Mathematician and Physicist Oskar Benjamin Klein ( September 15 1894 - February 5 1977) was a Swedish theoretical Physicist. In his last years, Albert Einstein was intensely occupied in finding such a unifying theory. Yet none of these attempts were successful. ^[6]

New discoveries

The search for a unifying theory was interrupted by the discovery of the strong and weak nuclear forces, which could not be subsumed into either gravity or electromagnetism. In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature A further hurdle was the acceptance that quantum mechanics had to be incorporated from the start, rather than emerging as a consequence of a deterministic unified theory, as Einstein had hoped. Gravity and electromagnetism could always peacefully coexist as entries in a list of Newtonian forces, but for many years it seemed that gravity could not even be incorporated into the quantum framework, let alone unified with the other fundamental forces. For this reason, work on unification for much of the twentieth century, focused on understanding the three "quantum" forces: electromagnetism and the weak and strong forces. The first two were unified in 1967–8 by Sheldon Glashow, Steven Weinberg, and Abdus Salam. In Particle physics, the electroweak interaction is the unified description of two of the four Fundamental interactions of nature Electromagnetism and the Sheldon Lee Glashow (born December 5, 1932) is an American physicist. Steven Weinberg (born May 3, 1933) is an American Physicist, and Nobel laureate in Physics for his contributions with Abdus Salam Abdus Salam ( Urdu: محمد عبد السلام) ( January 29, 1926; Jhang Punjab &ndash November 21, ^[7] The strong and electroweak forces peacefully coexist in the standard model of particle physics, but remain distinct. The Standard Model of Particle physics is a theory that describes three of the four known Fundamental interactions together with the Elementary particles Several Grand Unified Theories (GUTs) have been proposed to unify them. Grand Unification, grand unified theory, or GUT refers to any of several very similar unified field theories or models in Physics that Although the simplest GUTs have been experimentally ruled out, the general idea, especially when linked with supersymmetry, remains strongly favored by the theoretical physics community. In Particle physics, supersymmetry (often abbreviated SUSY) is a Symmetry that relates elementary particles of one spin to another particle that

Modern physics

In current mainstream physics, a Theory of Everything would unify all the fundamental interactions of nature, which are usually considered to be four in number: gravity, the strong nuclear force, the weak nuclear force, and the electromagnetic force. In Physics, a fundamental interaction or fundamental force is a mechanism by which particles interact with each other and which cannot be explained in terms Gravitation is a natural Phenomenon by which objects with Mass attract one another In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature In Physics, the electromagnetic force is the force that the Electromagnetic field exerts on electrically charged particles Because the weak force can transform elementary particles from one kind into another, the TOE should yield a deep understanding of the various different kinds of particles as well as the different forces. In Particle physics, an elementary particle or fundamental particle is a particle not known to have substructure that is it is not known to be made The expected pattern of theories is:

Theory of Everything

Gravity

Electronuclear force (GUT)

Strong force su(3)

Electroweak force su(2) x u(1)

Weak force su(2)

Electromagnetism u(1)

Electric force

Magnetic force

In addition to the forces listed here, modern cosmology might require an inflationary force, dark energy, and also dark matter composed of fundamental particles outside the scheme of the standard model. Gravitation is a natural Phenomenon by which objects with Mass attract one another Grand Unification, grand unified theory, or GUT refers to any of several very similar unified field theories or models in Physics that Grand Unification, grand unified theory, or GUT refers to any of several very similar unified field theories or models in Physics that In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and Special Unit 2In Mathematics, the special unitary group of degree n, denoted SU( n) is the group of n × n In Particle physics, the electroweak interaction is the unified description of two of the four Fundamental interactions of nature Electromagnetism and the Special Unit 2In Mathematics, the special unitary group of degree n, denoted SU( n) is the group of n × n In Mathematics, the unitary group of degree n, denoted U( n) is the group of n × n unitary matrices The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature Special Unit 2In Mathematics, the special unitary group of degree n, denoted SU( n) is the group of n × n Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of In Mathematics, the unitary group of degree n, denoted U( n) is the group of n × n unitary matrices In Physics, the space surrounding an Electric charge or in the presence of a time-varying Magnetic field has a property called an electric field (that can In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges Cosmology (from Greek grc κοσμολογία - grc κόσμος kosmos, "universe" and grc -λογία -logia) is study In Physical cosmology, cosmic inflation is the idea that the nascent Universe passed through a phase of exponential expansion that In Physical cosmology, dark energy is a hypothetical exotic form of Energy that permeates all of space and tends to increase the rate of expansion of the universe In Physics and cosmology, dark matter is hypothetical Matter that does not interact with the electromagnetic force but whose presence can be inferred from The existence of these has not been proven and there are alternative theories such as modified Newtonian dynamics. In Physics, Modified Newtonian dynamics ( MOND) is a theory that proposes a modification of Newton's Second Law of Dynamics (F = ma to explain

Electroweak unification is a broken symmetry: the electromagnetic and weak forces appear distinct at low energies because the particles carrying the weak force, the W and Z bosons have a mass of about 100 GeV, whereas the photon, which carries the electromagnetic force, is massless. Broken symmetry is a concept developed by Lee and Yang, used in Mathematics and Physics when an object breaks either Rotational symmetry The W and Z bosons are the Elementary particles that mediate the Weak force. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena At higher energies Ws and Zs can be created easily and the unified nature of the force becomes apparent. Matter creation is the process inverse to particle Annihilation. Grand unification is expected to work in a similar way, but at energies of the order of 10¹⁶ GeV, far greater than could be reached by any possible Earth-based particle accelerator. By analogy, unification of the GUT force with gravity is expected at the Planck energy, roughly 10¹⁹ GeV. In Physics, the unit of Energy in the system of Natural units known as Planck units is called the Planck energy, denoted by E P

It may seem premature to be searching for a TOE when there is as yet no direct evidence for an electronuclear force, and while in any case there are many different proposed GUTs. In fact the name deliberately suggests the hubris involved. Hubris, sometimes spelled hybris ( Ancient Greek ὕβρις is a term used in modern English to indicate overweening Pride, self-confidence Nevertheless, most physicists believe this unification is possible, partly due to the past history of convergence towards a single theory. Supersymmetric GUTs seem plausible not only for their theoretical "beauty", but because they naturally produce large quantities of dark matter, and the inflationary force may be related to GUT physics (although it does not seem to form an inevitable part of the theory). And yet GUTs are clearly not the final answer. Both the current standard model and proposed GUTs are quantum field theories which require the problematic technique of renormalization to yield sensible answers. In quantum field theory (QFT the forces between particles are mediated by other particles In Quantum field theory, the Statistical mechanics of fields and the theory of self-similar geometric structures renormalization refers to a collection This is usually regarded as a sign that these are only effective field theories, omitting crucial phenomena relevant only at very high energies. In Physics, an effective field theory is an approximate theory (usually a Quantum field theory) that includes appropriate degrees of freedom to describe Furthermore, the inconsistency between quantum mechanics and general relativity implies that one or both of these must be replaced by a theory incorporating quantum gravity. Quantum gravity is the field of Theoretical physics attempting to unify Quantum mechanics, which describes three of the fundamental forces of nature

The mainstream theory of everything at the moment is superstring theory / M-theory; current research on loop quantum gravity may eventually play a fundamental role in a TOE, but that is not its primary aim. This is a list of some of the major unsolved problems in Physics. String theory is a still-developing scientific approach to Theoretical physics, whose original building blocks are one-dimensional extended objects called strings See also String theory Superstring theory is an attempt to explain all of the particles and Fundamental forces of nature in one theory by modelling In Theoretical physics, M-theory is a new limit of String theory in which 11 dimensions of Spacetime may be identified See also String theory Superstring theory is an attempt to explain all of the particles and Fundamental forces of nature in one theory by modelling In Theoretical physics, M-theory is a new limit of String theory in which 11 dimensions of Spacetime may be identified Loop quantum gravity (LQG, also known as loop gravity and Quantum geometry, is a proposed quantum theory of Spacetime which attempts to reconcile the theories These theories attempt to deal with the renormalization problem by setting up some lower bound on the length scales possible. String theories and supergravity (both believed to be limiting cases of the yet-to-be-defined M-theory) suppose that the universe actually has more dimensions than the easily observed three of space and one of time. In Theoretical physics, supergravity ( supergravity theory) is a field theory that combines the principles of Supersymmetry and General relativity The motivation behind this approach began with the Kaluza-Klein theory in which it was noted that applying general relativity to a five dimensional universe (with the usual four dimensions plus one small curled-up dimension) yields the equivalent of the usual general relativity in four dimensions together with Maxwell's equations (electromagnetism, also in four dimensions). In Physics, Kaluza–Klein theory (or KK theory, for short is a model that seeks to unify the two fundamental forces of Gravitation and In Classical electromagnetism, Maxwell's equations are a set of four Partial differential equations that describe the properties of the electric This has led to efforts to work with theories with large number of dimensions in the hopes that this would produce equations that are similar to known laws of physics. The notion of extra dimensions also helps to resolve the hierarchy problem, which is the question of why gravity is so much weaker than any other force. The common answer involves gravity leaking into the extra dimensions in ways that the other forces do not.

In the late 1990s, it was noted that one problem with several of the candidates for theories of everything (but particularly string theory) was that they did not constrain the characteristics of the predicted universe. For example, many theories of quantum gravity can create universes with arbitrary numbers of dimensions or with arbitrary cosmological constants. In Physical cosmology, the cosmological constant (usually denoted by the Greek capital letter Lambda: Λ was proposed by Albert Einstein as a modification Even the "standard" ten-dimensional string theory allows the "curled up" dimensions to be compactified in an enormous number of different ways (one estimate is 10⁵⁰⁰) each of which corresponds to a different collection of fundamental particles and low-energy forces. In String theory, a model used in Theoretical physics, a compact dimension is curled up in itself and very small ( Planck length) This array of theories is known as the string theory landscape. The string theory landscape or anthropic landscape refers to the large number of possible false vacua in String theory.

A speculative solution is that many or all of these possibilities are realised in one or another of a huge number of universes, but that only a small number of them are habitable, and hence the fundamental constants of the universe are ultimately the result of the anthropic principle rather than a consequence of the theory of everything. In Physics and Cosmology, the anthropic principle states that humans should take into account the constraints that human existence imposes on the kind of theoretical This anthropic approach is often criticised in that, because the theory is flexible enough to encompass almost any observation, it cannot make useful (as in original, falsifiable, and verifiable) predictions. In this view, string theory would be considered a pseudoscience, where an unfalsifiable theory is constantly adapted to fit the experimental results. Pseudoscience is defined as a body of knowledge methodology belief or practice that is claimed to be Scientific or made to appear scientific but does not adhere to the

With reference to Gödel's incompleteness theorem

A small number of scientists claim that Gödel's incompleteness theorem proves that any attempt to construct a TOE is bound to fail. In Mathematical logic, Gödel's incompleteness theorems, proved by Kurt Gödel in 1931 are two Theorems stating inherent limitations of all but the most Gödel's theorem states that any non-trivial mathematical theory that has a finite description is either inconsistent or incomplete. In his 1966 book The Relevance of Physics, Stanley Jaki pointed out that, because any "theory of everything" will certainly be a consistent non-trivial mathematical theory, it must be incomplete. The Reverend Father Professor Stanley L Jaki OSB (b Győr, Hungary August 17 1924) is a Benedictine priest and Distinguished He claims that this dooms searches for a deterministic theory of everything. ^[8]

Freeman Dyson has stated that

“	Gödel’s theorem implies that pure mathematics is inexhaustible. Freeman John Dyson FRS (born December 15, 1923) is an English-born American theoretical Physicist and Mathematician, famous for his No matter how many problems we solve, there will always be other problems that cannot be solved within the existing rules. [. . . ] Because of Gödel's theorem, physics is inexhaustible too. The laws of physics are a finite set of rules, and include the rules for doing mathematics, so that Gödel's theorem applies to them.	„
—Freeman Dyson, NYRB, May 13, 2004

Stephen Hawking was originally a believer in the Theory of Everything but, after considering Gödel's Theorem, concluded that one was not obtainable. Stephen William Hawking CH, CBE, FRS, FRSA (born 8 January 1942 is a British theoretical physicist.

“	Some people will be very disappointed if there is not an ultimate theory, that can be formulated as a finite number of principles. I used to belong to that camp, but I have changed my mind.	„
—Stephen Hawking, Gödel and the end of physics, July 20, 2002

This view has been argued against by Jürgen Schmidhuber (1997), who pointed out that Gödel's theorems are irrelevant even for computable physics ^[9]. Jürgen Schmidhuber (born 1963 in Munich) is a Computer scientist and Artist known for his work on Machine learning, universal In 2000 Schmidhuber explicitly constructed limit-computable, deterministic universes whose pseudo-randomness based on undecidable, Gödel-like halting problems is extremely hard to detect but does not at all prevent formal TOEs describable by very few bits of information ^{[10] [11]}. A pseudorandom number generator ( PRNG) is an Algorithm for generating a sequence of numbers that approximates the properties of random numbers Undecidable has more than one meaning;In Mathematical logic: A Decision problem is called (recursively undecidable if no Algorithm can In computability theory, the halting problem is a Decision problem which can be stated as follows given a description of a program and a finite input

Related critique was offered by Solomon Feferman,^[12] among others. Solomon Feferman (b December 13, 1928) is an American Philosopher and Mathematician with major works in Mathematical logic Douglas S. Robertson offers Conway's game of life as an example:^[13] The underlying rules are simple and complete, but there are formally undecidable questions about the game's behaviors. "Conway game" can refer to games as defined by Surreal numbers which Conway also developed Analogously, it may (or may not) be possible to completely state the underlying rules of physics with a finite number of well-defined laws, but there is little doubt that there are questions about the behavior of physical systems which are formally undecidable on the basis of those underlying laws.

Since most physicists would consider the statement of the underlying rules to suffice as the definition of a "theory of everything", these researchers argue that Gödel's Theorem does not mean that a TOE cannot exist. On the other hand, the physicists invoking Gödel's Theorem appear, at least in some cases, to be referring not to the underlying rules, but to the understandability of the behavior of all physical systems, as when Hawking mentions arranging blocks into rectangles, turning the computation of prime numbers into a physical question. In Mathematics, a prime number (or a prime) is a Natural number which has exactly two distinct natural number Divisors 1 ^[14] This definitional discrepancy may explain some of the disagreement among researchers.

Potential status of a theory of everything

No physical theory to date is believed to be precisely accurate. Instead, physics has proceeded by a series of "successive approximations" allowing more and more accurate predictions over a wider and wider range of phenomena. Some physicists believe that it is therefore a mistake to confuse theoretical models with the true nature of reality, and hold that the series of approximations will never terminate in the "truth". Einstein himself expressed this view on occasions. ^[15] On this view, we may reasonably hope for a theory of everything which self-consistently incorporates all currently known forces, but should not expect it to be the final answer. On the other hand it is often claimed that, despite the apparently ever-increasing complexity of the mathematics of each new theory, in a deep sense associated with their underlying gauge symmetry and the number of fundamental physical constants, the theories are becoming simpler. Gauge theory is a peculiar Quantum field theory where the Lagrangian is invariant under certain transformations If so, the process of simplification cannot continue indefinitely.

There is a philosophical debate within the physics community as to whether a theory of everything deserves to be called the fundamental law of the universe. ^[16] One view is the hard reductionist position that the TOE is the fundamental law and that all other theories that apply within the universe are a consequence of the TOE. Reductionism can either mean (a an approach to understanding the nature of complex things by reducing them to the interactions of their parts or to simpler or more fundamental things Another view is that emergent laws (called "free floating laws" by Steven Weinberg), which govern the behavior of complex systems, should be seen as equally fundamental. For other uses see Emergence (disambiguation, Emergent, and Emergency. Steven Weinberg (born May 3, 1933) is an American Physicist, and Nobel laureate in Physics for his contributions with Abdus Salam This article describes complex system as a type of system For other meanings see Complex systems. Examples are the second law of thermodynamics and the theory of natural selection. The second law of Thermodynamics is an expression of the universal law of increasing Entropy, stating that the entropy of an Isolated system which Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of The point being that, although in our universe these laws describe systems whose behaviour could ("in principle") be predicted from a TOE, they would also hold in universes with different low-level laws, subject only to some very general conditions. Therefore it is of no help, even in principle, to invoke low-level laws when discussing the behavior of complex systems. Some argue that this attitude would violate Occam's Razor if a completely valid TOE were formulated. Occam's razor (sometimes spelled Ockham's razor) is a principle attributed to the 14th-century English Logician and Franciscan Friar, It is not clear that there is any point at issue in these debates (e. g. between Steven Weinberg and Philip Anderson) other than the right to apply the high-status word "fundamental" to their respective subjects of interest. Steven Weinberg (born May 3, 1933) is an American Physicist, and Nobel laureate in Physics for his contributions with Abdus Salam Philip Warren Anderson (born December 13, 1923) is an American Physicist.

Although the name "theory of everything" suggests the determinism of Laplace's quote, this gives a very misleading impression. Determinism is frustrated by the probabilistic nature of quantum mechanical predictions, by the extreme sensitivity to initial conditions that leads to mathematical chaos, and by the extreme mathematical difficulty of applying the theory. In Mathematics, chaos theory describes the behavior of certain dynamical systems – that is systems whose state evolves with time – that may exhibit dynamics that Thus, although the current standard model of particle physics "in principle" predicts all known non-gravitational phenomena, in practice only a few quantitative results have been derived from the full theory (e. g. the masses of some of the simplest hadrons), and these results (especially the particle masses which are most relevant for low-energy physics) are less accurate than existing experimental measurements. In Particle physics, a hadron ( from the ἁδρός hadrós, " stout, thick " ( The true TOE would almost certainly be even harder to apply. The main motive for seeking a TOE, apart from the pure intellectual satisfaction of completing a centuries-long quest, is that all prior successful unifications have predicted new phenomena, some of which (e. g. electrical generators) have proved of great practical importance. In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic As in other cases of theory reduction, the TOE would also allow us to confidently define the domain of validity and residual error of low-energy approximations to the full theory which could be used for practical calculations.

Theory of everything and philosophy

Main article: Theory of everything (philosophy)

The status of a physical TOE is open to philosophical debate. In philosophy a theory of everything or TOE is an ultimate all-encompassing explanation of Nature or Reality. Philosophy is the study of general problems concerning matters such as existence knowledge truth beauty justice validity mind and language For instance, if physicalism is true, a physical TOE would coincide with a philosophical theory of everything. Physicalism is a philosophical position holding that everything which exists is no more extensive than its Physical properties; that is that there are no kinds of things other Some philosophers (Aristotle, Plato, Hegel, Whitehead, et al) have attempted to construct all-encompassing systems. Aristotle (Greek Aristotélēs) (384 BC – 322 BC was a Greek philosopher a student of Plato and teacher of Alexander the Great. Biography Early life Birth and family Plato was born in Athens Greece Alfred North Whitehead, OM ( February 15 1861, Ramsgate, Kent, England &ndash December 30 1947, Others are highly dubious about the very possibility of such an exercise.

See also

• An exceptionally simple theory of everything based on Wilhelm Killing's E₈
• Holographic principle

References

Further reading

• John D. Barrow, Theories of Everything: The Quest for Ultimate Explanation (OUP, Oxford, 1990) ISBN 0-099-98380-X
• Stephen Hawking 'The Theory of Everything: The Origin and Fate of the Universe' is an unauthorized 2002 book taken from recorded lectures (ISBN 1-893224-79-1)
• Stanley Jaki OSB, 2005. John David Barrow FRS (born November 29, 1952, London) is an English cosmologist, theoretical physicist, and Stephen William Hawking CH, CBE, FRS, FRSA (born 8 January 1942 is a British theoretical physicist. The Theory of Everything The Origin and Fate of the Universe is an unauthorized 2002 book by Stephen Hawking (ISBN 1-893224-79-1 The Reverend Father Professor Stanley L Jaki OSB (b Győr, Hungary August 17 1924) is a Benedictine priest and Distinguished The Drama of Quantities. Real View Books (ISBN 1-892548-47-X)
• Abraham Pais Subtle is the Lord. Abraham (Bram Pais (May 19 1918 Amsterdam, The Netherlands &mdash July 28 2000 Copenhagen, Denmark) was a Dutch -born American . . : The Science and the Life of Albert Einstein (OUP, Oxford, 1982). ISBN 0-19-853907-X
• Steven Weinberg Dreams of a Final Theory: The Search for the Fundamental Laws of Nature (Hutchinson Radius, London, 1993) ISBN 0-09-1773954

External links

• The Elegant Universe-Nova online — a 3 hour PBS show about the search for the Theory of everything and string theory. Steven Weinberg (born May 3, 1933) is an American Physicist, and Nobel laureate in Physics for his contributions with Abdus Salam
• 'Theory of Everything' Freeview video by the Vega Science Trust and the BBC/OU
• 'An Exceptionally Simple Theory of Everything' A. Garrett Lisi
• Papers on algorithmic theories of everything (1997-2007) by Jürgen Schmidhuber

Antony Garrett Lisi (born January 24, 1968; uses the name Garrett by preference is an American-born Theoretical physicist and adventure Jürgen Schmidhuber (born 1963 in Munich) is a Computer scientist and Artist known for his work on Machine learning, universal

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