A multiverse (or meta-universe) is the hypothetical set of multiple possible universes (including our universe) that together comprise all of physical reality. The different universes within a multiverse are sometimes called parallel universes. The structure of the multiverse, the nature of each universe within it and the relationship between the various constituent universes, depend on the specific multiverse hypothesis considered. For other uses, see Universe (disambiguation). ... For other uses, see Reality (disambiguation). ... Parallel universe, alternate reality, etc. ...

Multiverses have been hypothesized in cosmology, physics, philosophy, theology, and fiction, particularly in science fiction and fantasy. The specific term "multiverse," which was coined by William James,^{[citation needed]} was popularized by science fiction author Michael Moorcock. In these contexts, parallel universes are also called "alternate universes," "quantum universes," "parallel worlds," "alternate realities," "alternate timelines," etc. Cosmology, from the Greek: κοσμολογία (cosmologia, κόσμος (cosmos) order + λογια (logia) discourse) is the study of the Universe in its totality, and by extension, humanitys place in it. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... For other uses, see Philosophy (disambiguation). ... Theology finds its scholars pursuing the understanding of and providing reasoned discourse of religion, spirituality and God or the gods. ... For other uses, see Fiction (disambiguation). ... Science fiction is a form of speculative fiction principally dealing with the impact of imagined science and technology, or both, upon society and persons as individuals. ... For other uses, see Fantasy (disambiguation). ... This article needs additional references or sources for verification. ... Michael John Moorcock (born December 18, 1939, in London, England) is a prolific English writer primarily of science fiction and fantasy who has also published a number of literary novels. ...

The possibility of many universes raises various scientific, philosophical, and theological questions.

Multiverse hypotheses in physics

Classification

According to Max Tegmark,^[1] the existence of other universes is a direct implication of cosmological observations. Tegmark describes the set of related concepts which share the notion that there are universes beyond the familiar observable one, and goes on to provide a taxonomy of parallel universes organized by levels.^[2] In order to clarify terminology, George Ellis, U. Kirchner and W.R. Stoeger recommend using the term "the Universe" for the theoretical model of the whole of the causally connected spacetime in which we live, universe domain for the observable universe or a similar part of the same space-time, "universe" for a general space-time, either our own "Universe" or another one disconnected from our own, multiverse for a set of disconnected space-times, and multi-domain universe to refer to a model of the whole of a single connected space-time in the sense of chaotic inflation models.^[3] Max Tegmark Max Tegmark born 1967 in Sweden to Karin Tegmark and Harold S Shapiro, is a cosmologist formerly at the University of Pennsylvania and now at the Massachusetts Institute of Technology as an Associate Professor. ... George Ellis is the Distinguished Professor of Complex Systems at the University of Cape Town (South Africa), in the Department of Mathematics and Applied Mathematics. ... A Möbius strip, an object with only one surface and one edge; such shapes are an object of study in topology. ... For other uses of this term, see Spacetime (disambiguation). ... In mathematics, a set can be thought of as any collection of distinct objects considered as a whole. ... The theory created by Andrei Linde that states that our universe could have come from nothing more than hundred-thousandth of a gram of matter. ...

The levels according to Tegmark's classification and using Ellis, Koechner and Stoeger's terminology are briefly described below.

Multi-domain universes (Ellis, Koechner and Stoeger sense):

Level I: (Open multiverse) A generic prediction of cosmic inflation is an infinite ergodic universe, which, being infinite, must contain Hubble volumes realizing all initial conditions - including an identical copy of a given person about m away. In physical cosmology, cosmic inflation is the idea that the nascent universe passed through a phase of exponential expansion that was driven by a negative-pressure vacuum energy density. ... The infinity symbol ∞ in several typefaces. ... In physics and thermodynamics, the ergodic hypothesis says that, over long periods of time, the time spent in some region of the phase space of microstates with the same energy is proportional to the volume of this region, i. ... A Hubble volume refers to a volume of space, usually defined as a cube where each axis is approximately 13. ... This article is about the unit of length. ...

Level II: (Andrei Linde's bubble theory) In chaotic inflation, other thermalized regions may have different effective physical constants, dimensionality and particle content. (Surprisingly, this level includes Wheeler's oscillating universe theory as well.) Andrei Linde is an American physicist and professor of Physics at Californias Stanford University. ... It has been suggested that this article or section be merged with Chaotic inflation theory. ... The theory created by Andrei Linde that states that our universe could have come from nothing more than hundred-thousandth of a gram of matter. ... In physics, a physical constant is a physical quantity of a value that is generally believed to be both universal in nature and not believed to change in time. ... The oscillatory universe is a cosmological model, originally derived by Alexander Friedman in 1922 and developed by Richard Tolman from 1934, in which the universe undergoes a series of oscillations, each beginning with a big bang and ending with a big crunch. ...

Multiverses (Ellis, Koechner and Stoeger sense)

Level III: (Hugh Everett III's many-worlds interpretation) An interpretation of quantum mechanics that proposes the existence of multiple universes, all of which are "identical", but exist in possibly different states. It is widely believed that Everett's interpretation (considered as a formal theory) is a conservative extension of standard quantum mechanics -- that is, as far as results expressible in the language of ordinary quantum mechanics are concerned, it leads to no new results. This, according to Tegmark, "is ironic given that this level has historically been the most controversial". Hugh Everett III (November 11, 1930 – July 19, 1982) was an American physicist who first proposed the many-worlds interpretation(MWI) of quantum physics, which he called his relative state formulation. ... The many-worlds interpretation or MWI (also known as relative state formulation, theory of the universal wavefunction, many-universes interpretation, Oxford interpretation or many worlds), is an interpretation of quantum mechanics that claims to resolve all the paradoxes of quantum theory by allowing every possible outcome to every event to... For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... // Definition A logical theory T2 is a conservative extension of theory T1 if any consequence of T2 involving symbols of T1 only is already a consequence of T1. ...

Level IV: (The ultimate "Ensemble theory" of Tegmark) Other mathematical structures give different fundamental equations of physics. This level considers "real" any hypothetical universe based on one of these structures. M-theory might be placed here. Since this subsumes all other possible ensembles, it brings closure to the hierarchy of multiverses: there cannot be a Level V. The question is open whether or not scientists will subdivide Level IV in the future. The Ultimate Ensemble is a speculative possible feature of theories of everything (TOEs), suggested by Max Tegmark. ... M-theory is a solution proposed for the unknown theory of everything which would combine all five superstring theories and 11-dimensional supergravity together. ...

Open multiverse

Open universe, in the Universe, there are many observable areas(The observable areas are marked as red circles with red crosses on the center), our "universe" is one of the observable areas

Some physicists believe that the universe is spatially unbounded^{[citation needed]}. The theory of relativity places a firm upper limit on the speed at which information can travel. Nothing except hypothetically Tachyons can travel faster than light. This effectively divides this infinite space into "local" universes. Our observable universe, for example, is a sphere centered on the Earth (centered, that is, on whoever is doing the calculating), currently about 46.5 billion light years in radius. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Two-dimensional analogy of space-time curvature described in General Relativity. ... A tachyon (from the Greek (takhús), meaning swift, fast) is any hypothetical particle that travels at superluminal velocity. ... See universe for a general discussion of the universe. ... A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in vacuum in one year. ...

Thus, there are an infinite number of regions of space the same size as our observable universe -- an infinite number of observable universes, that is. This infinite set (which must contain, among other things, an infinite number of identical copies of you,^[4] the nearest of which is about m away, and an equally infinite number of not-quite-identical copies) comprises the level-I multiverse. By the Bekenstein bound there are only a finite number of configurations possible within any region, hence exact duplication is inevitable. Space has been an interest for philosophers and scientists for much of human history. ... See universe for a general discussion of the universe. ... In set theory, an infinite set is a set that is not a finite set. ... This article is about the unit of length. ... In physics, the Bekenstein bound imposes a limit on the entropy S or information that can be contained within a three-dimensional volume. ...

Overtly or not, physicists often use the idea of an Open Multiverse when evaluating theories. For example, Max Tegmark writes: Max Tegmark Max Tegmark born 1967 in Sweden to Karin Tegmark and Harold S Shapiro, is a cosmologist formerly at the University of Pennsylvania and now at the Massachusetts Institute of Technology as an Associate Professor. ...

...consider how cosmologists used the microwave background to rule out a finite spherical geometry. Hot and cold spots in microwave background maps have a characteristic size that depends on the curvature of space, and the observed spots appear too small to be consistent with a spherical shape. But it is important to be statistically rigorous. The average spot size varies randomly from one Hubble volume to another, so it is possible that our universe is fooling us--it could be spherical but happen to have abnormally small spots. When cosmologists say they have ruled out the spherical model with 99.9 percent confidence, they really mean that if this model were true, fewer than one in 1,000 Hubble volumes would show spots as small as those we observe.

Bubble theory

"Bubble universes", every disk is a bubble universe (Universe 1 to Universe 6 are different bubbles, they have physical constants that are different from our universe), our universe is just one of the bubbles.

Bubble theory posits an infinite number of open multiverses, each with different physical constants. (The set of bubble universes is thus a Level II multiverse.) Counter-intuitively, these universes are farther away than even the farthest universe in our open multiverse. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... In physics, a physical constant is a physical quantity of a value that is generally believed to be both universal in nature and not believed to change in time. ...

The formation of our universe from a "bubble" of a multiverse was proposed by Andre Linde. This Bubble universe theory fits well with the widely accepted theory of cosmic inflation. The bubble universe concept involves creation of universes from the quantum foam of a "parent universe." On very small scales, the foam is frothing due to energy fluctuations. These fluctuations may create tiny bubbles and wormholes. If the energy fluctuation is not very large, a tiny bubble universe may form, experience some expansion like an inflating balloon, and then contract and disappear from existence. However, if the energy fluctuation is greater than a particular critical value, a tiny bubble universe forms from the parent universe, experiences long-term expansion, and allows matter and large-scale galactic structures to form. Andrei Linde is an American physicist and professor of Physics at Californias Stanford University. ... It has been suggested that this article or section be merged with Chaotic inflation theory. ... In physical cosmology, cosmic inflation is the idea that the nascent universe passed through a phase of exponential expansion that was driven by a negative-pressure vacuum energy density. ... This article needs to be cleaned up to conform to a higher standard of quality. ... For other uses, see Wormhole (disambiguation). ... The bubble universe model is a variant of the inflationary model of the big bang. ...

Big bounce

According to some quantum loop gravity theorists, the Big Bang was merely the beginning of a period of expansion that followed a period of contraction. In this oscillatory universe hypothesis (originally attributable to John Wheeler), the universe undergoes an infinite series of oscillations, each beginning with a big bang and ending with a big crunch. After the big bang, the universe expands for a while before the gravitational attraction of matter causes it to collapse back in and undergo a Big bounce. Although the model was abandoned for a time, the theory has been revived in brane cosmology as the cyclic model. Loop quantum gravity (LQG), also known as loop gravity and quantum geometry, is a proposed quantum theory of spacetime which attempts to reconcile the seemingly incompatible theories of quantum mechanics and general relativity. ... For other uses, see Big Bang (disambiguation). ... The oscillatory universe is a cosmological model, originally derived by Alexander Friedman in 1922 and developed by Richard Tolman from 1934, in which the universe undergoes a series of oscillations, each beginning with a big bang and ending with a big crunch. ... John Archibald Wheeler (born July 9, 1911) is an eminent American theoretical physicist. ... This article is about the cosmological theory. ... This article does not cite any references or sources. ... Brane cosmology is a protoscience motivated by, but not rigorously derived from, superstring theory and M-theory. ... The cyclic model is a brane cosmology model of the creation of the universe, derived from the earlier ekpyrotic model. ...

Like Bubble Theory, this oscillatory view posits a Level-II multiverse.

Many worlds interpretation of quantum physics

Hugh Everett's many-worlds interpretation (MWI) is one of several mainstream interpretations of quantum mechanics. Other interpretations include the Copenhagen and the consistent histories interpretations. The multiverse proposed by MWI has a shared time parameter. In most formulations, all the constituent universes are structurally identical to each other and though they have the same physical laws and values for the fundamental constants, they may exist in different states. The constituent universes are furthermore non-communicating, in the sense that no information can pass between them. The state of the entire multiverse is related to the states of the constituent universes by quantum superposition, and is described by a single universal wavefunction. Related are Richard Feynman's multiple histories interpretation and H. Dieter Zeh's many-minds interpretation. Hugh Everett III (November 11, 1930 – July 19, 1982) was an American physicist who first proposed the many-worlds interpretation(MWI) of quantum physics, which he called his relative state formulation. ... The many-worlds interpretation or MWI (also known as relative state formulation, theory of the universal wavefunction, many-universes interpretation, Oxford interpretation or many worlds), is an interpretation of quantum mechanics that claims to resolve all the paradoxes of quantum theory by allowing every possible outcome to every event to... It has been suggested that Quantum mechanics, philosophy and controversy be merged into this article or section. ... The Copenhagen interpretation is an interpretation of quantum mechanics formulated by Niels Bohr and Werner Heisenberg while collaborating in Copenhagen around 1927. ... In quantum mechanics, the consistent histories approach is intended to give a modern interpretation of quantum mechanics, generalising the conventional Copenhagen interpretation and providing a natural interpretation of quantum cosmology. ... Quantum superposition is the application of the superposition principle to quantum mechanics. ... The Universal Wavefunction is a term introduced by Hugh Everett in his Princeton PhD Thesis[1], entitled The Theory of the Universal Wavefunction and forms a core concept in the relative state interpretation[2][3] or many-worlds interpretation[4][5] of quantum mechanics. ... This article is about the physicist. ... The concept of multiple histories is closely related to the many-worlds interpretation of quantum mechanics. ... This article needs to be cleaned up to conform to a higher standard of quality. ... The many-minds interpretation of quantum mechanics extends the many-worlds interpretation by proposing that the distinction between worlds should be made at the level of the mind of an individual observer. ...

Many worlds interpretation cannot explain the apparently Fine-tuned universe. The physical constants of all the “many worlds” are the same. Many worlds interpretation can, however explain the apparent improbability of a planet like Earth existing. See Rare Earth hypothesis. If the Many worlds interpretation is true there are so many copies of our universe that the existence of at least one planet like Earth is not surprising. The deepest visible-light image of the cosmos. ... This article is about Earth as a planet. ... The Rare Earth hypothesis is a hypothesis in planetary astronomy and astrobiology which argues that the emergence of complex multicellular life (metazoa) on Earth required an extremely unlikely combination of astrophysical and geological events and circumstances. ...

M-theory

A multiverse of a somewhat different kind has been envisaged within the 11-dimensional extension of string theory known as M-theory. In M-theory our universe and others are created by collisions between membranes in an 11-dimensional space. Unlike the universes in the "quantum multiverse", these universes can have different laws of physics. 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 String theory is a model of fundamental physics, whose building blocks are one-dimensional extended objects called strings, rather than the zero-dimensional point... M-theory is a solution proposed for the unknown theory of everything which would combine all five superstring theories and 11-dimensional supergravity together. ... The many-worlds interpretation or MWI (also known as relative state formulation, theory of the universal wavefunction, many-universes interpretation, Oxford interpretation or many worlds), is an interpretation of quantum mechanics that claims to resolve all the paradoxes of quantum theory by allowing every possible outcome to every event to... For other uses, see Universe (disambiguation). ...

String landscape

The string landscape theory asserts that a different universe exists for each of the very large ensemble of solutions generated when ten dimensional string theory is reduced to the four-dimensional low-energy world we see. The string theory landscape or anthropic landscape refers to the large number of different false vacua in string theory. ...

Criticisms of multiverse theories

Non-scientific claims

Critics claim that these theories lack empirical correlation and testability, and without hard physical evidence are unfalsifiable; outside the methodology of scientific investigation to confirm or disprove; and therefore more mathematically theoretical and metaphysical than scientific in nature. In philosophy generally, empiricism is a theory of knowledge emphasizing the role of experience in the formation of ideas, while discounting the notion of innate ideas. ... 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... Falsifiability (or refutability or testability) is the logical possibility that an assertion can be shown false by an observation or a physical experiment. ... Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. ... Plato (Left) and Aristotle (right), by Raphael (Stanza della Segnatura, Rome) Metaphysics is the branch of philosophy concerned with explaining the ultimate nature of reality, being, and the world. ...

Tegmark notes that improved measurements of the microwave background radiation and of the large-scale distribution of matter may fortify or knock down two pillars of the multiverse -- the infinitude of space and the theory of chaotic inflation -- so at least part of the theory may be testable. However, chaotic inflation is not the only version of cosmic inflation that can lead naturally to the multiverse hypothesis, as "new inflation" is also eternal and offers a scientific justification of the anthropic principle. Furthermore, not all models of inflation are eternal. “CMB” redirects here. ... In physical cosmology, cosmic inflation is the idea that the nascent universe passed through a phase of exponential expansion that was driven by a negative-pressure vacuum energy density. ... In physics and cosmology, the anthropic principle is an umbrella term for various dissimilar attempts to explain the structure of the universe by way of coincidentally balanced features that are necessary and relevant to the existence of observers (usually assumed to be carbon-based life or even specifically human beings). ...

Bad science

Some have argued that the job of a scientist is to provide fundamental explanations for observed Phenomena, without making reference to observers. Resorting to anthropic principles constitutes a "lazy way out" of accounting for features such as the apparent fine-tuning of parameters in relation to the existence of life.

Leonard Susskind claims, however, that some form of multiverse is unavoidable, given the current state of physics, and that observer effects are inevitable and have to be taken into account in other sciences. Leonard Susskind (born 1940[1]) is the Felix Bloch professor of theoretical physics at Stanford University in the field of string theory and quantum field theory. ...

Occam's Razor

To postulate an infinity of unseen and unseeable verses just to explain the one we do see seems like a case of excess baggage carried to the extreme. Template:Veryshort 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 14th-century English logician and Franciscan friar William of Ockham. ...

Tegmark answers:"A common feature of all four multiverse levels is that the simplest and arguably most elegant theory involves parallel verses by default. To deny the existence of those verses, one needs to complicate the theory by adding experimentally unsupported processes and ad hoc postulates: finite space, wave function collapse and ontological asymmetry. Our judgment therefore comes down to which we find more wasteful and inelegant: many worlds or many words."^[5] Thus, according to Tegmark, paradoxically the multiverse scenario is more parsimonious than that of a single verse. In certain interpretations of quantum mechanics, wavefunction collapse is one of two processes by which quantum systems apparently evolve according to the laws of quantum mechanics. ...

One unique universe

It is sometimes argued ^{[citation needed]} that the observed universe is the unique possible universe, so that talk of “other” universes is ipso facto meaningless. Einstein raised this possibility when he wondered whether the universe could have been otherwise, or non-existent altogether. This possibility is also expressed in theories such as determinism and chaos theory ^{[citation needed]}. The hope is sometimes expressed that once a grand unified theory of everything is achieved, it will turn out to have a unique “solution” corresponding to the observed universe. “Einstein” redirects here. ... Determinism is the philosophical proposition that every event, including human cognition and behavior, decision and action, is causally determined by an unbroken chain of prior occurrences. ... For other uses, see Chaos Theory (disambiguation). ... This article or section is in need of attention from an expert on the subject. ...

Creating more problems

Multiverse proponents are often vague about how the parameter values are selected across the defined ensemble. If there is a “law of laws” or meta-law describing how parameter values are assigned from one universe to the next, then we have only shifted the central problems of cosmology up one level, because we need to explain where the meta-law comes from. Moreover, the set of such meta-laws is infinite, so we have merely replaced the question “why this universe?” with “why this meta-law?”. There would seem to be little point in invoking an infinite number of universes when it would be simpler to postulate a single universe with a single principle. There is no reason to assume that any meta-law is fine-tuned. We do not know whether or not any meta-law would have to be in a narrow range to allow at least one universe like ours. We do not know enough about any meta-law to say whether it needs to be fine-tuned or can be coarsely-tuned.

Tegmark maintains that in his extreme multiverse theory this problem is circumvented, because in that case all possible meta-laws (or all possible unified theories) are in force and describe really-existing multiverses. However, his ultimate ensemble is still restricted to mathematical (or mathematically describable) laws, processes and structures. If it is in any way possible for something non-mathematical to exist, his ensemble is not ultimate, and relies on a contingent meta-law law excluding the non-mathematical from actual existence. The Ultimate Ensemble is a speculative possible feature of theories of everything (TOEs), suggested by Max Tegmark. ...

Other objections

Another objection to the existing multiverse theories is a challenge to the criteria for defining universes. In most multiverse theories, universes are labeled by laws of physics and initial conditions. It might be argued that these terms are narrow and chauvinistic; there may be criteria for categorization that lie completely beyond the scope of human comprehension. In mathematics, boundary conditions are imposed on the solutions of ordinary differential equations and partial differential equations, to fit the solutions to the actual problem. ...

However, any algorithmic form is covered by Max Tegmark's ultimate ensemble. In mathematics, computing, linguistics, and related disciplines, an algorithm is a finite list of well-defined instructions for accomplishing some task that, given an initial state, will terminate in a defined end-state. ... The Ultimate Ensemble is a speculative possible feature of theories of everything (TOEs), suggested by Max Tegmark. ...

The entire range of multiverse hypotheses, with specific emphasis on Hugh Everett's many-worlds interpretation, have been criticised by proponents of intelligent design. William Dembski in particular, derides it as inflating explanatory resources without evidence or warrant, and terms such concepts "inflatons".^[6] For other uses, see Intelligent design (disambiguation). ... William Dembski Dr William Albert Bill Dembski (born July 18, 1960) is an American mathematician, philosopher and theologian known for advocating the controversial idea of intelligent design. ... The inflaton is the generic name of the unidentified scalar field (and its associated particle), that may be responsible for an episode of inflation in the very early universe. ...

Anthropic principle

Main article: Anthropic principle

The concept of other universes has been proposed to explain why our universe seems to be fine-tuned for conscious life as we experience it. If there were a large number (possibly infinite) of different physical laws (or fundamental constants) in as many universes, some of these would have laws that were suitable for stars, planets and life to exist. The anthropic principle could then be applied to conclude that we would only consciously exist in those universes which were finely-tuned for our conscious existence. Thus, while the probability might be extremely small that there is life in most of the multiverses, this scarcity of life-supporting universes does not imply intelligent design as the only explanation of our existence. In physics and cosmology, the anthropic principle is an umbrella term for various dissimilar attempts to explain the structure of the universe by way of coincidentally balanced features that are necessary and relevant to the existence of observers (usually assumed to be carbon-based life or even specifically human beings). ... The deepest visible-light image of the cosmos. ... For other uses, see Life (disambiguation). ... A teleological argument, or argument from design, is an argument for the existence of God or a creator based on perceived evidence of order, purpose, design and/or direction in nature. ...

Critics of this argument (Steven Jay Gould, Richard Dawkins and many others) point out that the cause and the effect have been reversed by those who claim that the universe seems to be fine-tuned for our benefit. Dr. Gould compared it to claiming that hotdogs were originally made long and narrow so that they would fit modern hotdog buns, or that humans evolved fingernails because fingernail polish would inevitably be invented. Critics cite the vast store of evolutionary evidence which shows that life is perfectly and naturally tuned to the universe it arose in. Fossil, genetic and other biological evidence abundantly supports the observation that life adapts to physics, not the other way around.

The paleophysicist Caroline Miller writes: "The Anthropic Principle is based on the underlying belief that the universe was created for our benefit. Unfortunately for it's adherents, all of the reality-based evidence at our disposal contradicts this belief. In a non-anthropocentric universe, there is no need for multiple universes or supernatural entities to explain life as we know it."

Modal realism

Additionally, possible worlds are a way of explaining probability, hypothetical statements and the like, and some philosophers such as David Lewis believe that all possible worlds exist, and are just as real as the actual world (a position known as modal realism).^[7] In philosophy and logic, the concept of possible worlds is used to express modal claims. ... David Kellogg Lewis (September 28, 1941 – October 14, 2001) is considered to have been one of the leading analytic philosophers of the latter half of the 20th century. ... Modal realism is the view, notably propounded by David Lewis, that possible worlds are as real as the actual world. ...

Trans-world identity issues

A metaphysical issue that crops up with multiverse schema that posit infinite identical copies of any given universe is that of the notion that there can be identical objects in different possible worlds. David Lewis then defened his counterpart theory where he substitutes the identity relation between possible worlds for a similarity relation. Counterpart theory (hereafter CT) is a theoretical framework that uses the counterpart relation (hereafter C-relation) as a replacement for the identity relation between objects in different possible world/times/spaces. ...

The problem lies in the tension between classical notions of identity and quantum indeterminacy. In short, quantum reality does not allow classical - radically mechanical - 'identities' due to the Heisenberg Uncertainty Principle. However, in an infinite set of possible universes such a correspondence is presumed to exist. The question then becomes whether one can claim a distinction between entities that vary only in terms of some arbitrary dimensional metric in De Sitter space. In philosophy, identity is whatever makes an entity definable and recognizable, in terms of possessing a set of qualities or characteristics that distinguish it from entities of a different type. ... Quantum indeterminacy is the apparent necessary incompleteness in the description of a physical system, that has become one of the characteristics of the standard description of quantum physics. ... In quantum physics, the outcome of even an ideal measurement of a system is not deterministic, but instead is characterized by a probability distribution, and the larger the associated standard deviation is, the more uncertain we might say that that characteristic is for the system. ... In mathematics and physics, n-dimensional de Sitter space, denoted , is the maximally symmetric, simply-connected, Lorentzian manifold with constant positive curvature. ...

Suggested resolutions include the possibilities that:

• Synchronous unitemporal parallel universe ontologies are invalid.
• Synchronous unitemporal parallel universes belong to a part-whole relationship.
• Quantum fluctuations average out within the Heisenberg limit between duplicates.
• Alternate criteria are needed to hermeneutically assess the concept of 'identity’.

Trans-world identity is also considered in depth in possible worlds concepts.^[8][9] The identity of indiscernibles is an ontological principle; i. ... In quantum physics, a quantum fluctuation is the temporary change in the amount of energy in a point in space, arising from Werner Heisenbergs uncertainty principle. ... Hermeneutics may be described as the development and study of theories of the interpretation and understanding of texts. ... In philosophy and logic, the concept of possible worlds is used to express modal claims. ...

Virtual realities as a multiverse

Further information: Simulated reality

Most scientists are prepared to entertain the possibility of conscious machines^{[citation needed]}, and some artificial intelligence advocates even claim we are not far from producing conscious computers.^{[citation needed]} It is then but a small step to the point where the engineered conscious beings inhabit a simulated reality. For such beings, their “fake” universe will appear indistinguishable from reality. So should we include these simulated universes in the ensemble that constitutes the multiverse? Is it meaningful to assign equal ontological status to our own, observed, universe and universes that are virtual? If it is not then is it meaningful to assign equal ontological status to our own, observed, universe and universes that can never be observed by any sentient being? Simulated reality is the idea that reality could be simulated — often computer-simulated — to a degree indistinguishable from true reality. ... Bold text[[Link title]] “AI” redirects here. ... Digitalism may refer to: Digital philosophy Digitalism, a New Rave duo from Hamburg, Germany ... Simulated reality is the idea that reality could be simulated — often computer-simulated — to a degree indistinguishable from true reality. ... This article is about ontology in philosophy. ...

Incidentally, this of course assumes that our observed universe is 'real' and not virtual; at least one philosopher, Nick Bostrom, has proposed that this may not be the case. Nick Bostrom (Boström in the original Swedish) is a philosopher at the University of Oxford, and known for his work on the anthropic principle. ...

Multiverse hypotheses in philosophy

Hindu universes

The earliest known records describing the concept of a multiverse are found in ancient Hindu cosmology, in texts such as the Puranas. They expressed the idea of an infinite number of universes, each with its own gods, inhabitants and planets, and an infinite cycle of births, deaths, and rebirths of a universe, with each cycle lasting 8.4 billion years. The belief is too that the number of universes are infinite.^[10] // an egg broke and out came the planets thanks to gods pet hen The Rig Veda describes the origin of the universe as: Then was not non-existence nor existence: there was no realm of air, no sky beyond it. ... Purana (Sanskrit: , meaning tales of ancient times) is the name of an ancient Indian genre (or a group of related genres) of Hindu or Jain literature (as distinct from oral tradition). ...

Other contemporary religious references

Main article: Mormon cosmology

The Church of Jesus Christ of Latter Day Saints (the "Mormon Church") has a concept which dovetails somewhat with theories of multiple universes, though there is no church position on this.^{[citation needed]} The Church of Jesus Christ of Latter-day Saints (often referred to as the Mormon church) teaches that God is not only the God of this world, but the God of the Universe. ...

Fictional multiverses

Main article: Parallel universe (fiction)

The concept of the multiverse figures prominently in many science fiction and fantasy novels. For some it serves primarily as a plot device, a means to put characters into an unfamiliar situation, or a framework that usually lies in the background for continuity purposes. For others it is a major theme and focus of the work. It is sometimes used as the basis for exploring "what if" scenarios, such as in alternate history stories. The TV show Sliders from the 1990's first popularized the concept through the TV entertainment medium. The film The One (2002) starring Jet Li carried the same idea to the action film medium. The popular MYST computer game franchise uses concepts of describing a world and then linking to that world, which is part of a multiverse of infinite possible and concurrently existing universes, matching the descriptions. Also, the computer game Legacy of Kain: Soul Reaver and its sequels feature two distinct parallel universes. The protagonist, Raziel, is capable of existing in both the Material Realm, or normal reality, and the Spectral Realm, a dark and distorted version of the former with its own physics and properties. The Michael Crichton novel Timeline featured a method for what appeared to be time travel by traveling to parallel universes that are identical except for the moment of their birth, thus rendering off-set yet parallel time. The DC Universe, famous home of Batman and Superman, uses the multiverse as the basis for their universe. This is in part to help deal with their 67 year history. In the 1980s DC published the ever popular Crisis on Infinite Earths which detailed a breakdown of the Multiverse at the hands of the Anti-Monitor. The television series Star Trek has many times gone into parallel "Mirror" universes, and Stargate SG-1 has postulated parallel universes. The Anime series Bokurano is based on a multi verse where the many earths must fight each other to see which shall continue to exist. Parallel universe or alternate reality in science fiction and fantasy is a self-contained separate reality coexisting with our own. ... Science fiction is a form of speculative fiction principally dealing with the impact of imagined science and technology, or both, upon society and persons as individuals. ... Alternate history (fiction) - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Sliders is a science fiction television series that ran for five seasons from 1995 to 2000. ... The One was an action movie released in 2001, starring Jet Li and Carla Gugino. ... Jet Li (born Li Lianjie on April 26, 1963 in Beijing, China) is a Chinese martial artist, actor, Wushu champion, and international film star. ... Myst (or MYST) is a graphic adventure computer game designed and directed by the brothers Robyn and Rand Miller. ... Michael Crichton, pronounced [1], (born October 23, 1942) is an American author, film producer, film director, and television producer. ... Timeline is a science fiction novel by Michael Crichton that was published in November 1999. ... Cover to the History of the DC Universe trade paperback. ... Batman (originally referred to as the Bat-Man and still referred to at times as the Batman) is a DC Comics fictional superhero who first appeared in Detective Comics #27 in May 1939. ... Superman is a fictional character and comic book superhero , originally created by American writer Jerry Siegel and Canadian artist Joe Shuster and published by DC Comics. ... Crisis on Infinite Earths was a 12-issue comic book limited series (identified as a 12-part maxi-series) and crossover event, produced by DC Comics in 1985 in order to simplify their fifty-year-old continuity. ... The Anti-Monitor is a fictional comic book supervillain, the antagonist of the 1985 DC Comics miniseries Crisis on Infinite Earths. ... The current Star Trek franchise logo Star Trek is an American science fiction entertainment series and media franchise. ... Stargate SG-1 (often abbreviated as SG-1) is a science fiction television series, part of the Stargate franchise. ...

References

• Deutsch, David (45841 1985). in Splash: Quantum theory, the Church-Turing principle and the universal quantum computer, Proceedings of the Royal Society of London A 400, mos craciun, 97-117. iulianveza12@yahoo.com. 

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 38th day of the year in the Gregorian calendar. ... George Ellis is the Distinguished Professor of Complex Systems at the University of Cape Town (South Africa), in the Department of Mathematics and Applied Mathematics. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 9th day of the year in the Gregorian calendar. ... Insert non-formatted text here Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer and astrobiologist and a highly successful popularizer of astronomy, astrophysics, and other natural sciences. ...

See also

• The Fabric of Reality
• Fictional universe
• Multiple histories
• Parallel universe
• Philosophy of physics
• Philosophy of space and time
• Quantum gravity
• Reductionism
• Simulated reality
• String theory landscape
• His Dark Materials
• Counterpart theory

The Fabric of Reality is a 1997 book by physicist David Deutsch, which expands upon his views of quantum mechanics and its meanings for understanding reality. ... A fictional universe is an imaginary world that serves as the setting or backdrop for one or (more commonly) multiple works of fiction or translatable non-fiction. ... The concept of multiple histories is closely related to the many-worlds interpretation of quantum mechanics. ... Parallel universe or alternate reality in science fiction and fantasy is a self-contained separate reality coexisting with our own. ... Philosophy of physics is the study of the fundamental, philosophical questions underlying modern physics, the study of matter and energy and how they interact. ... Philosophy of space and time is the branch of philosophy concerned with the issues surrounding the ontology, epistemology, and character of space and time. ... Quantum gravity is the field of theoretical physics attempting to unify quantum mechanics, which describes three of the fundamental forces of nature, with general relativity, the theory of the fourth fundamental force: gravity. ... Descartes held that non-human animals could be reductively explained as automata — De homines 1622. ... Simulated reality is the idea that reality could be simulated — often computer-simulated — to a degree indistinguishable from true reality. ... The string theory landscape or anthropic landscape refers to the large number of different false vacua in string theory. ... The trilogy (U.K versions), in order of succession from left to right. ... Counterpart theory (hereafter CT) is a theoretical framework that uses the counterpart relation (hereafter C-relation) as a replacement for the identity relation between objects in different possible world/times/spaces. ...

External links

• Preprint of David Deutsch's paper The Structure of the Multiverse
• BBC Horizon -Parallel Universes
• Michael Price's Everett FAQ
• Many Worlds & Parallel Universes — additional background information
• Against Many-Worlds Interpretations Adrian Kent, The Institute for Advanced Study, School of Natural Sciences, Princeton, New Jersey
• Multiverses and Cosmology: Philosophical Issues W. R. Stoeger1,, G. F. R. Ellis, and U. Kirchner. Department of Mathematics and Applied Mathematics, University of Cape Town; Vatican Observatory Research Group, Steward Observatory, The University of Arizona, Tucson, Arizona
• Mulitverse Cosmological Models by P.C.W. Davies