Theory of everything

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A theory of everything (TOE) is a theory of theoretical physics and mathematics that fully explains and links together all known physical phenomena. 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 "General Theory of Everything" (Polish: "Ogólna Teoria Wszystkiego"). Over time, the term stuck in popularizations of quantum physics to describe a theory that would unify the theories of the four fundamental interactions of nature.

There have been numerous theories of everything proposed by theoretical physicists over the last century, but as yet none has been able to stand up to experimental scrutiny or there is tremendous difficulty in getting the theories to produce even experimentally testable results. The primary problem in producing a TOE is that the accepted theories of quantum mechanics and general relativity propose radically different descriptions of the universe, and straightforward ways of combining the two lead quickly to the renormalization problem in which the theory does not give finite results for experimentally testable quantities.

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Mainstream physics

Albert Einstein was the first well-known scientist who spent most of his life trying to find a TOE; he believed that the only task was to unify general relativity and electromagnetism.

Current mainstream physics concepts require a TOE to unify the four fundamental interactions of nature: gravity, the strong nuclear force, the weak nuclear force, and the electromagnetic force; it should also explain the spectrum of elementary particles. There has been progress toward a TOE in unifying electromagnetism and the weak nuclear force in an electroweak unified field theory and in unifying all of the forces except for gravity (which in the present theory of general relativity is not a force) in the grand unification theory. One missing piece in a theory of everything involves combining quantum mechanics and general relativity into a theory of quantum gravity.

Image:Livechat michio kaku2.jpg The only mainstream candidate for a 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. These theories attempt to deal with the renormalization problem by setting up some lower bound on the length scales possible. Also, early 21st century theories of everything tend to suppose that the universe actually has more dimensions than the easily observed three of space and one of time. The motivation behind this approach began with the Kaluza-Klein theory in which it was noted that adding one dimension to general relativity would produce the electromagnetic Maxwell's equations. This has led to efforts to work with theories with large number of dimensions in the hopes that this would produce equations which 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 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. One bit of speculation is that there may indeed be 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. Max Tegmark has taken this principle to its logical conclusion with his "Ultimate Ensemble", whose only postulate is that "all structures that exist mathematically exist also physically". In this theory, certain mathematical structures are complex enough to contain self aware substructures, who subjectively perceive themselves as existing in a physically real world.

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There is also a philosophical debate within the physics community as to whether or not a "theory of everything" should be seen as the fundamental law of the universe. One view is the hard reductionist view that the TOE is the fundamental law of the universe and that all other theories of the universe are a consequence of the TOE. Another view is that there are laws which Steven Weinberg calls free floating laws which govern the behavior of complex systems, and while these laws are related to the theory of everything, they cannot be seen as less fundamental than the TOE. Some argue that this explanation would violate Occam's Razor if a completely valid TOE were formulated.

Other possibilities which may frustrate the explanatory capacity of a TOE may include sensitivity to the boundary conditions of the universe, or the existence of mathematical chaos in its solutions, making its predictions precise, but useless.

There have been several attempts to advance the general theory of relativity as a theory of everything. As mentioned above, Einstein was responsible for one of these: in collaboration with Rosen he attempted to model particles as tiny wormholes, hence the term Einstein-Rosen Bridge. Wormholes have also been proposed at various times (for instance, by Shimony and by Durand [1]) to explain Bell violations not as superluminal influences but influences that take a shortcut through a wormhole. Such theories face a number of hurdles: the creation of wormholes changes the topology of spacetime by creating a new "handle" which implies violations of causality (see Hadley [2]), and the general theory of relativity predicts its own breakdown at a Gravitational singularity by theorems of Stephen Hawking and Roger Penrose. A recent effort to surmount this hurdle notes that the equivalence principle can be applied along curves rather than at a single point (Iliev [3]), which would imply that time dilation of <math>(1-v^2)^{-1/2}</math> is indistinguishable locally (along the curve) from a relative velocity <math>v</math> and the unbounded time dilation observed as an event horizon emerges at the center of a collapsing star implies that the center is in reality as well as appearance receding at a velocity approaching the speed of light, producing a bubble-like local inflation of the star's interior (Monroe [4]). This approach skirts the trapped surface assumption of the singularity theorems of Hawking and Penrose. It posits that quantum behavior is an emergent phenomenon in general relativity caused by a stochastic gravitational background radiation (Calogero [5]), in which collidating gravitational waves create virtual particle pairs in the form of wormholes (Griffiths [6]), and the interference pattern in the two-slit experiment is caused by interference between gravitational wavefronts.

Other efforts

Template:Expert Attempts to create theories of everything are common among people outside the professional physics community. Some are created by amateurs, and their theories are often criticised on the basis of inability to make quantifiable and/or falsifiable predictions. For example, a theory of everything would provide some insight into the relative strength of forces, and predictions of particle lifetimes and cross sections. It would need to be shown to explain all known universal phenomena. Unlike professional physicists, who are generally aware that their proposed theory is incomplete, untested, and likely to be wrong and who are aware of the huge difficulties and challenges involved in creating a TOE, amateurs who create TOE's tend to be unaware of what work has already been done, the mechanisms for testing scientific theories and the fact that most proposed theories are wrong.

Burkhard Heim and quantised general relativity

Some supporters of the so-called Heim theory characterize this as a successful quantization of general relativity or even as a theory of everything, but neither of these claims are accepted in mainstream theoretical physics. In recent years it has been slowly emerging from obscurity. One sign of this was the award of a prize by the AIAA for a paper by Hauser & Droscher on Aerospace applications in 2005, although some have questioned whether an aerospace engineering prize is a reliable guide to the validity of the underlying theoretical physics. Its supporters claim that Heim theory has accurately predicted features such as particle masses and coupling constants. Critics contend that these claims are invalid and that work on Heim theory is flawed in a variety of ways.

Burkhard Heim's intent was to create a unified framework to model quantitative and qualitative aspects of our reality. He regarded himself largely successful, however his works are very inaccessible even to experts in the field of theoretical physics due their native complexity. He himself once said that the mass formula is simple in contrast to the syntrometic method, a mathematical framework he created in order to quantiatively and qualitatively describe any phenomenon within the realm of reality such as thoughts and consciousness (qualitative) in the presence of neural networks (quantitative).

Eino Kaila

The prolific Finnish philosopher Eino Kaila attempted to construct a theory of everything based on the philosophical implications of quantum mechanics in the 1950s. His attempt did not get much attention outside Finland, and he only managed to write the first part of what he planned on making an extensive study on the subject. "Terminalkausalität als die Grundlage eines unitarischen Naturbegriffs" ("terminal causality as the foundation of a unitarian notion of nature"), published in 1956, formulated a new type of causality and was meant to be followed by similar works on psychology and biology.

Expansion Theory

Expansion Theory purports to offer a theory of everything in which all physical phenomena are explained by universal accelerating expansion. Author Mark McCutcheon described the theory in the book The Final Theory: Rethinking our Scientific Legacy, in 2002, although the theory itself is much older. The theory argues that current scientific theory is inconsistent and incomplete in that it predicts yet doesn't explain Action at a distance, violates its own conservation laws, and fails to live up to experimental data or concur with the laws of common sense. Under expansion theory, Classical Mechanics, General Relativity, Special Relativity, Quantum Mechanics are discarded and replaced with an atomic expansion that, according to the author, accounts for phenomena like magnetism, light, gravity, and atomic forces. [7]

Expansion Theory holds little to no acceptance within the scientific community. Many of the predictions of the theory don't hold empirically, and the theory doesn't explain any anomalous data. Like other purported theories of everything, many regard the theory to be a form of pseudoscience.

See also

References

External links

de:Weltformel fr:Théorie de Tout he:תיאוריה מאוחדת גדולה it:Teoria del tutto pl:Teoria wszystkiego ru:Теория всего zh:万有理论