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Fine-Tuned Universe

ContentsArticles

Fine-tuned Universe 1Anthropic principle 9Multiverse 22Chaotic Inflation theory 28Calculating God 30

ReferencesArticle Sources and Contributors 32Image Sources, Licenses and Contributors 33

Article LicensesLicense 34

Fine-tuned Universe 1

Fine-tuned UniverseThe fine-tuned Universe is the idea that the conditions that allow life in the Universe can only occur when certainuniversal fundamental physical constants lie within a very narrow range, so that if any of several fundamentalconstants were only slightly different the universe would be unlikely to be conducive to the establishment anddevelopment of matter, astronomical structures, elemental diversity, or life as it is presently understood.[1]

The existence and extent of fine-tuning in the universe is a matter of dispute in the scientific community. Proponentsof fine-tuning include physicist Paul Davies who has stated "There is now broad agreement among physicists andcosmologists that the universe is in several respects ‘fine-tuned' for life".[2] Other physicists such as Victor Stengerdispute fine-tuning, saying that even though "life as we know it would not exist if any one of several of the constantsof physics were just slightly different, [we] cannot prove that some other form of life is feasible with a different setof constants. Anyone who insists that our form of life is the only one conceivable is making a claim based on noevidence and no theory."[3] Among scientists who find the evidence persuasive, a variety of scientific explanationshave been proposed, e.g., the anthropic principle along with multiple universes. The idea has also attracteddiscussion among philosophers and theologians, as well as creationists and proponents of the Intelligent Designmovement.

Premise

Fine-tuned Universe proponents argue that deep-space structures such as the Eta CarinaeNebula would not form in a universe with significantly different physical constants.

The premise of the fine-tuned universeassertion is that a small change inseveral of the dimensionlessfundamental physical constants wouldmake the universe radically different.As Stephen Hawking has noted, "Thelaws of science, as we know them atpresent, contain many fundamentalnumbers, like the size of the electriccharge of the electron and the ratio ofthe masses of the proton and theelectron. ... The remarkable fact is thatthe values of these numbers seem tohave been very finely adjusted to make possible the development of life."[4]

If, for example, the strong nuclear force were 2% stronger than it is (i.e., if the coupling constant representing itsstrength were 2% larger), while the other constants were left unchanged, diprotons would be stable and hydrogenwould fuse into them instead of deuterium and helium. This would drastically alter the physics of stars, andpresumably preclude the existence of life similar to what we observe on Earth. However, many of the fundamentalconstants describe the properties of the unstable strange, charmed, bottom and top quarks and mu and tau leptonswhich seem to play little part in the universe or the structure of matter.

The precise formulation of the idea is made difficult by the fact that physicists do not yet know how many independent physical constants there are. The current standard model of particle physics has 25 freely adjustable parameters (there is an additional parameter for gravitation, the cosmological constant). However, because the standard model is not mathematically self-consistent under certain conditions (e.g., at very high energies, at which both quantum mechanics and general relativity are relevant), physicists believe that it is underlaid by some other theory, such as a grand unified theory, string theory, or loop quantum gravity. In some candidate theories, the actual number of independent physical constants may be as small as 1. For example, the cosmological constant may be a

Fine-tuned Universe 2

fundamental constant, but attempts have also been made to calculate it from other constants, and according to theauthor of one such calculation, "the small value of the cosmological constant is telling us that a remarkably preciseand totally unexpected relation exists among all the parameters of the Standard Model of particle physics, the barecosmological constant and unknown physics."[5]

Martin Rees[6] formulates the fine-tuning of the universe in terms of the following six dimensionless constants:• N = ratio of the strength of electromagnetism to that of gravity;• Epsilon (ε) = strength of the force binding nucleons into nuclei;• Omega (ω) = relative importance of gravity and expansion energy in the universe;• Lambda (λ) = cosmological constant;• Q = ratio of the gravitational energy required to pull a large galaxy apart to the energy equivalent of its mass;• D = number of spatial dimensions in spacetime.

Disputes on the extent and existence of fine-tuningComputer simulations suggest that not all of the purportedly "fine-tuned" parameters may be as fine-tuned as hasbeen claimed. Victor Stenger has simulated different universes in which four fundamental parameters are varied. Hefound that long-lived stars could exist over a wide parameter range, and concluded that "... a wide variation ofconstants of physics leads to universes that are long-lived enough for life to evolve, although human life need notexist in such universes".[7] However Stenger's work has been criticised as having several fundamental flaws by otherphysicists.[8] [9]

Fred Adams has done a similar study to Stenger, investigating the structure of stars in universes with different valuesof the gravitational constant G, the fine-structure constant α, and a nuclear reaction rate parameter C. His studysuggests that roughly 25% of this parameter space allows stars to exist.[10] However, Adams has been criticised formaking unjustified assumptions.[11] Harnik, Kribs and Perez have argued for the viability of a universe with no weakinteraction at all. However, they noted that their analysis does not extend to the supposed fine tuning of thecosmological constant, and concluded that "the fine-tuning problems associated with the electroweak breaking scaleand the cosmological constant appear to be qualitatively different from the perspective of obtaining a habitableuniverse."[12]

The validity of fine tuning examples is sometimes questioned on the grounds that such reasoning is subjectiveanthropomorphism applied to natural physical constants. Critics also suggest that the fine-tuned universe assertionand the anthropic principle are essentially tautologies.[13] The fine-tuned universe argument has also been criticizedas an argument by lack of imagination because it assumes no other forms of life, sometimes referred to as carbonchauvinism. Conceptually, alternative biochemistry or other forms of life are possible.[14] In addition, critics arguethat humans are adapted to the universe through the process of evolution, rather than the universe being adapted tohumans (see puddle thinking). They also see it as an example of the logical flaw of hubris or anthropocentrism in itsassertion that humans are the purpose of the universe.[15]

Possible naturalistic explanationsThere are fine tuning arguments that are naturalistic.[16] As modern cosmology developed, various hypotheses havebeen proposed. One is an oscillatory universe or a multiverse where physical constants are postulated to resolvethemselves to random values in different iterations of reality.[17] Under this hypothesis, separate parts of realitywould have wildly different characteristics. In such scenarios the issue of fine-tuning does not arise at all, as onlythose "universes" with constants hospitable to life (such as what we observe) would develop life capable of askingthe question.Based upon the Anthropic principle, physicist Robert H. Dicke proposed the "Dicke coincidence" argument that the structure (age, physical constants, etc.) of the universe as seen by living observers is not random, but is constrained

Fine-tuned Universe 3

by biological factors that require it to be roughly a "golden age".[18]

MultiverseThe Multiverse hypothesis assumes the existence of many universes with different physical constants, some of whichare hospitable to intelligent life (see multiverse: anthropic principle). Because we are intelligent beings, we are bydefinition in a hospitable one. Mathematician Michael Ikeda and astronomer William H. Jefferys have argued thatthe anthropic principle resolves the entire issue of fine-tuning,[19] [20] as does philosopher of science Elliott Sober.[21]

Philosopher and theologian Richard Swinburne reaches the opposite conclusion using Bayesian probability.[22]

This approach has led to considerable research into the anthropic principle and has been of particular interest toparticle physicists because theories of everything do apparently generate large numbers of universes in which thephysical constants vary widely. As of yet, there is no evidence for the existence of a multiverse, but some versions ofthe theory do make predictions which some researchers studying M-theory and gravity leaks hope to see someevidence of soon.[23] The existence of additional universes in a multiverse, other than the observable universe, is notfalsifiable, and thus some are reluctant to call the multiverse idea a "scientific" idea. UNC-Chapel Hill professorLaura Mersini-Houghton claims that the WMAP cold spot may provide testable empirical evidence for a paralleluniverse.Variants on this approach include Lee Smolin's notion of cosmological natural selection, the Ekpyrotic universe, andthe Bubble universe theory.Critics of the multiverse-related explanations argue that there is no evidence that other universes exist.

Bubble universe theory

The bubble universe model by physicist Andrei Linde, postulates that our universe is one of many that grew from amultiverse consisting of vacuum that had not yet decayed to its ground state.

According to this scenario, by means of a random quantum fluctuation the universe "tunneled" from purevacuum ("nothing") to what is called a false vacuum, a region of space that contains no matter or radiation butis not quite "nothing." The space inside this bubble of false vacuum was curved, or warped. A small amount ofenergy was contained in that curvature, somewhat like the energy stored in a strung bow. This ostensibleviolation of energy conservation is allowed by the Heisenberg uncertainty principle for sufficiently small timeintervals.The bubble then inflated exponentially and the universe grew by many orders of magnitude in a tiny fractionof a second. (For a not-too-technical discussion, see Stenger 1990). As the bubble expanded, its curvatureenergy was converted into matter and radiation, inflation stopped, and the more linear big bang expansion wenow experience commenced. The universe cooled and its structure spontaneously froze out, as formless watervapor freezes into snowflakes whose unique patterns arise from a combination of symmetry and randomness.—Victor J. Stenger, The Anthropic Coincidences[24]

In standard inflation, inflationary expansion occurred while the universe was in a false vacuum state, halting whenthe universe decayed to a true vacuum state. The bubble universe model proposes that different parts of thisinflationary universe (termed a Multiverse) decayed at different times, with decaying regions corresponding touniverses not in causal contact with each other. It further supposes that each bubble universe may have differentphysical constants.

Fine-tuned Universe 4

Top-down cosmology

Stephen Hawking, along with Thomas Hertog of CERN, proposed that the universe's initial conditions consisted of asuperposition of many possible initial conditions, only a small fraction of which contributed to the conditions we seetoday.[25] According to their theory, it is inevitable that we find our universe's "fine-tuned" physical constants, as thecurrent universe "selects" only those past histories that led to the present conditions. In this way, top-downcosmology provides an anthropic explanation for why we find ourselves in a universe that allows matter and life,without invoking the current existence of a multiverse.

Alien designOne hypothesis is that the Universe may have been designed by extra-universal aliens. Some believe this wouldsolve the problem of how a designer or design team capable of fine-tuning the Universe could come to exist.Cosmologist Alan Guth believes humans will in time be able to generate new universes. By implication previousintelligent entities may have generated our universe.[26] This idea leads to the possibility that the extraterrestrialdesigner/designers are themselves the product of an evolutionary process in their own universe, which must thereforeitself be able to sustain life. For instance, Richard Dawkins maintains that an alien designer or designers are moreplausible than a supernatural designer or designers because there is a known mechanism to produce them. He calls itthe “crane” of Natural selection. Dawkins' claims, though, are criticized among philosophers (e.g. RichardSwinburne, Alvin Plantinga, Nancey Murphy) to just push back the problem further (now it would be no more thecase to explain this universe, but the universe in which those aliens live), and it could be argued that the resultinguniverse where the aliens live calls even more for a designer that would be eternal and uncreated (that is God).Further, in Richard Dawkins' ultimate Boeing 747 gambit he explains that evolution is an even more plausible"crane".The Simulation hypothesis promoted by Nick Bostrom and others suggests that our universe may be a computersimulation by aliens.[27]

The Biocosm hypothesis and the Meduso-anthropic principle both suggest that natural selection has made theuniverse biophilic. The universe enables intelligence because intelligent entities later create new biophilic universes.This is different from the suggestion above that aliens from a universe which is less finely tuned than ours made ouruniverse finely tuned.

Religious opinionsAs with theistic evolution, some individual scientists, theologians, and philosophers as well as certain religiousgroups argue that providence or creation are responsible for fine-tuning.Christian philosopher Alvin Plantinga argues[28] that random chance, applied to a single and sole universe, onlyraises the question as to why this universe could be so "lucky" as to have precise conditions that support life at leastat some place (the Earth) and time (within millions of years of the present).

One reaction to these apparent enormous coincidences is to see them as substantiating the theistic claimthat the universe has been created by a personal God and as offering the material for a properlyrestrained theistic argument—hence the fine-tuning argument. It's as if there are a large number of dialsthat have to be tuned to within extremely narrow limits for life to be possible in our universe. It isextremely unlikely that this should happen by chance, but much more likely that this should happen ifthere is such a person as God.

This apparent fine-tuning of the universe is cited[29] by theologian and philosopher William Lane Craig as anevidence for the existence of God or some form of intelligence capable of manipulating (or designing) the basicphysics that governs the universe. Craig argues, however, "that the postulate of a divine Designer does not settle forus the religious question."

Fine-tuned Universe 5

Variants on this approach include:

Intelligent designProponents of Intelligent design argue that certain features of the universe and of living things are best explained byan intelligent cause, not an undirected process such as natural selection. The fine-tuned universe argument is acentral premise or presented as a given in many of the published works of prominent Intelligent Design proponents,such as William A. Dembski and Michael Behe.

Other religious creation viewsMost religions have some kind of account of the creation of the universe, although they generally differ in detailfrom the ones listed above. Some of these may be compatible with known scientific facts. For examplescientist-theologians such as John Polkinghorne emphasize the implications of Anthropic Fine-Tuning within anorthodox Christian framework whilst fully accepting the scientific findings about Evolution and the age of theUniverse. This is also the position of the Roman Catholic Church and of most Anglican theologians.[30] The Jewishphysicist Gerald Schroeder argues that the apparent discrepancy between the "days" in Genesis and the billions ofyears in a scientific understanding are due to the differences in frames of reference. Many other religious creationviews are either incompatible with, or indifferent to, scientific understandings. Other scientists with similar views arephysicist Freeman Dyson and astronomer Owen Gingerich.

Counter argument to religious viewsVictor Stenger argues that "... The fine-tuning argument and other recent intelligent design arguments are modernversions of God of the gaps reasoning, where a God is deemed necessary whenever science has not fully explainedsome phenomenon".[7]

The argument from imperfection suggests that if the universe were designed to be fine-tuned for life, it should be thebest one possible and that evidence suggests that it is not.[31] In fact, most of the universe is highly hostile to life.Additionally Stenger argues, "We have no reason to believe that our kind of carbon-based life is all that is possible.Furthermore, modern cosmology indicates that multiple universes may exist with different constants and laws ofphysics. So, it is not surprising that we live in the one suited for us. The universe is not fine-tuned to life; life isfine-tuned to the universe."[32]

In fiction and popular culture• Robert J. Sawyer discusses the fine-tuned universe at length in his novel Calculating God (2000).• Author Neal Stephenson discussed the issue of fine-tuning in the conclusion to his essay In the Beginning... was

the Command Line.[33]

• Puddle thinking is a satirical illustration of the "life is fine-tuned to the universe" argument above coined byDouglas Adams to satirize the Fine-tuned Universe argument for supernatural creationism.[34] [35] As quoted inRichard Dawkins' eulogy for Douglas Adams:[36]

... imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in,an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact it fits me staggeringly well,must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky andthe air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on tothe notion that everything's going to be all right, because this world was meant to have him in it, wasbuilt to have him in it; so the moment he disappears catches him rather by surprise. I think this may besomething we need to be on the watch out for.

Fine-tuned Universe 6

CriticismThe proposal that the universal laws of the cosmos are finely tuned (regarding intelligent life) fails as it is based onthe assumption that present, complex life existed as a given.[37] [38] (The proposition is flawed as it applies to life aswe know it, not life, strictly.) The claim is ignorant to the fact that life has evolved to suit the standards of theuniverse—or the "tuning" of the universe.[39] [40] [41] A "finely tuned" universe is down to human judgement, thusreducing or omitting the proposal's objectivity.[42]

References[1] Mark Isaak (ed.) (2005). "CI301: The Anthropic Principle" (http:/ / www. talkorigins. org/ indexcc/ CI/ CI301. html). Index to Creationist

Claims. TalkOrigins Archive. . Retrieved 2007-10-31.[2] Paul Davies, "How bio-friendly is the universe?" International Journal of Astrobiology, vol. 2, no. 2 (2003): 115.[3] Victor Stenger, (http:/ / www. colorado. edu/ philosophy/ vstenger/ anthro. html) "The Uncreated Universe" (http:/ / www. colorado. edu/

philosophy/ vstenger/ Found/ 06Cosmic. pdf) Has Science Found God?: The Latest Results in the Search for Purpose in the Universe,Prometheus Books, ISBN 1591020182.

[4] Stephen Hawking, 1988. A Brief History of Time, Bantam Books, ISBN 0-553-05340-X, p. 125.[5] Larry Abbott, "The Mystery of the Cosmological Constant," Scientific American, vol. 3, no. 1 (1991): 78.[6] Martin Rees, 1999. Just Six Numbers, HarperCollins Publishers, ISBN 0-465-03672-4.[7] Is The Universe Fine-Tuned For Us? (http:/ / www. colorado. edu/ philosophy/ vstenger/ Cosmo/ FineTune. pdf#search="Fine tuned

universe") Victor J. Stenger, University of Colorado.[8] Luke Barnes (2010). "What Chances Me? A Fine Tuned Critique of Victor Stenger (Part 1)" (http:/ / letterstonature. wordpress. com/ 2010/

04/ 11/ what-chances-me-a-fine-tuned-critique-of-victor-stenger-part-1/ ). Letters to Nature. Letters to Nature. . Retrieved 2010-09-03.[9] Luke Barnes (2010). "No Faith In MonkeyGod: A Fine-Tuned Critique of Victor Stenger (Part 2)" (http:/ / letterstonature. wordpress. com/

2010/ 04/ 18/ no-faith-in-monkeygod-a-fine-tuned-critique-of-victor-stenger-part-2/ ). Letters to Nature. Letters to Nature. . Retrieved2010-09-03.

[10] Adams, F.C. (2008). "Stars in other universes: stellar structure with different fundamental constants". Journal of Cosmology andAstroparticle Physics 2008 (08): 010. arXiv:0807.3697. Bibcode 2008JCAP...08..010A. doi:10.1088/1475-7516/2008/08/010.

[11] Luke Barnes (2010). "The Shrinking Quarter: A Fine-Tuned Critique of Fred Adams" (http:/ / letterstonature. wordpress. com/ 2010/ 02/ 28/the-shrinking-quarter-a-fine-tuned-critique-of-fred-adams/ ). Letters to Nature. Letters to Nature. . Retrieved 2010-09-03.

[12] Harnik, R.; Kribs, G.D. and Perez, G. (2006). "A universe without weak interactions". Physical Review D 74: 035006.arXiv:hep-ph/0604027. Bibcode 2006PhRvD..74c5006H. doi:10.1103/PhysRevD.74.035006.

[13] See, e.g., Our place in the Multiverse (http:/ / www. nature. com/ nature/ journal/ v443/ n7108/ full/ 443145a. html) Joseph Silk. Nature,Volume 443 Number 7108, September 14, 2006.

[14] See, e.g. Jack Cohen and Ian Stewart: What Does a Martian Look Like: The Science of Extraterrestrial Life, Wiley, 2002[15] See, e.g., Gerald Feinberg and Robert Shapiro, "A Puddlian Fable" in Huchingson, Religion and the Natural Sciences (1993), pp. 220-221[16] L. Susskind, The cosmic landscape: string theory and the illusion of intelligent design. (Little, Brown, 2005)[17] Wheeler, J. A. (1977) in Foundational problems in the special sciences, Reidel, Dordrecht, pp 3–33[18] Dicke, R. H. (1961). "Dirac's Cosmology and Mach's Principle". Nature 192 (4801): 440–441. Bibcode 1961Natur.192..440D.

doi:10.1038/192440a0.[19] The Anthropic Principle Does Not Support Supernaturalism (http:/ / quasar. as. utexas. edu/ anthropic. html), Michael Ikeda, Bill Jefferys[20] Michael Ikeda and William H. Jefferys, "The Anthropic Principle Does Not Support Supernaturalism," in The Improbability of God,

Michael Martin and Ricki Monnier, Editors, pp. 150-166. Amherst, N.Y.: Prometheus Press. ISBN 1-59102-381-5.[21] Elliott Sober, 2004. The Design Argument, in The Blackwell Guide to the Philosophy of Religion, W. E. Mann, Editor. Blackwell

Publishing, ISBN 0-631-22129-8.[22] Richard Swinburne, 1990. Argument from the fine-tuning of the universe, in Physical cosmology and philosophy, J. Leslie, Editor. Collier

Macmillan: New York. pp. 154-73.[23] Parallel Worlds,2005, Michio Kaku, pp. 220-221[24] The Anthropic Coincidences (http:/ / www. colorado. edu/ philosophy/ vstenger/ Cosmo/ anthro_skintel. html)[25] Ball, Philip (June 21, 2006). "Hawking Rewrites History...Backwards" (http:/ / www. nature. com/ news/ 2006/ 060619/ full/ news060619-6.

html). Nature News Online. . Retrieved April 19, 2010.[26] BBC - Science & Nature - Horizon - Parallel Universes - Transcript (http:/ / www. bbc. co. uk/ science/ horizon/ 2001/ parallelunitrans.

shtml)[27] Bostrom, N. (2002). Anthropic Bias: Observation Selection Effects in Science and Philosophy. Routledge, New York. ISBN 0-415-93858-9.[28] Alvin Plantinga, "The Dawkins Confusion; Naturalism ad absurdum," Christianity Today, March/April 2007 (http:/ / www. philvaz. com/

apologetics/ DawkinsGodDelusionPlantingaReview. pdf)[29] William Lane Craig, "The Teleological Argument and the Anthropic Principle," (http:/ / www. leaderu. com/ offices/ billcraig/ docs/ teleo.

html)

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[30] See, e.g., Alister McGrath's books Scientific Theology and The Science of God.[31] Avitel Pilpel, SKEPTIC, November 2007 Issue, p.18[32] Victor Stenger, Flew's Flawed Science (http:/ / www. mukto-mona. com/ Articles/ vstenger/ flew. htm)[33] In The Beginning Was The Command Line (http:/ / www. cryptonomicon. com/ beginning. html)[34] Williams, Robyn (18). "The anthropic universe" (http:/ / www. abc. net. au/ rn/ scienceshow/ stories/ 2006/ 1572643. htm). The Science

Show (ABC Radio National). . Retrieved 19 November 2009.[35] Redfern, Martin (24 December 1995). "Proofs of God in a photon" (http:/ / www. independent. co. uk/ arts-entertainment/

proofs-of-god-in-a-photon-1527306. html). The Independent. . Retrieved 19 November 2009.[36] Dawkins, Richard (17 September 2001). "Eulogy for Douglas Adams" (http:/ / www. edge. org/ documents/ adams_index. html). Edge. .

Retrieved 19 November 2009.[37] Ross Hugh , "Astronomical evidences for a personal, transcendent God. In: The Creation Hypothesis 1994, pp. 141-172. J. P. Moreland, ed.,

Downers Grove, IL: InterVarsity Press[38] http:/ / www. talkorigins. org/ indexcc/ CI/ CI301. html[39] Mayr, Ernst 1982. The growth of biological thought. Harvard. p483: "Adaptation... could no longer be considered a static condition, a

product of a creative past, and became instead a continuing dynamic process."[40] The Oxford Dictionary of Science defines adaptation as "Any change in the structure or functioning of an organism that makes it better

suited to its environment".[41] ttp://www.futurefoundation.org/documents/che_pro_wrk3.pdf[42] http:/ / www. talkorigins. org/ indexcc/ CI/ CI301. html

Further reading• [ Edit this reference (http:/ / en. wikipedia. org/ w/ index. php?title=Template:BarrowTipler1986& action=edit)]

Barrow, John D.; Tipler, Frank J. (19 May 1988). The Anthropic Cosmological Principle (http:/ / books. google.com/ books?id=uSykSbXklWEC& printsec=frontcover). foreword by John A. Wheeler. Oxford: Oxford UniversityPress. ISBN 9780192821478. LC 87-28148 (http:/ / lccn. loc. gov/ 87028148). Retrieved 31 December 2009.• John D. Barrow, 2003. The Constants of Nature, Pantheon Books, ISBN 0-375-42221-8• Bernard Carr, ed. (2007) Universe or Multiverse? Cambridge University Press.• Paul Davies, 1982. The Accidental Universe, Cambridge University Press, ISBN 0-521-24212-6• Paul Davies, 2007. Cosmic Jackpot: Why Our Universe Is Just Right for Life, Houghton Mifflin Harcourt, ISBN

0618592261. Reprinted as: The Goldilocks Enigma: Why Is the Universe Just Right for Life?, 2008, MarinerBooks, ISBN 0547053584.

• Alister McGrath, 2009. A Fine-Tuned Universe: The Quest for God in Science and Theology, Westminster JohnKnox Press, ISBN 0664233104.

• Simon Conway Morris, 2003. Life's Solution: Inevitable Humans in a Lonely Universe. Cambridge Univ. Press.• Peter Ward and Donald Brownlee, 2000. Rare Earth: Why Complex Life is Uncommon in the Universe. Springer

Verlag.

External linksDefend fine-tuning:• God: new evidence – a series of six videos exploring how evidence from cosmic fine tuning points to the reality

of a creator God (http:/ / www. focus. org. uk/ )• Stephen M. Barr (2001) " Overview of the Cosmological Intelligent Design argument, (http:/ / www. firstthings.

com/ ftissues/ ft0106/ articles/ barr. html)" First Things, the Journal of Religion, Culture, and Public Life.• Robin Collins:

• Fine-Tuning website. (http:/ / home. messiah. edu/ ~rcollins/ )• " Cosmological fine-tuning. (http:/ / academic. udayton. edu/ WilliamRichards/ Intro essays/ Collins,

Fine-tuning. htm)"• Hugh Ross:

• " Design and the Anthropic Principle. (http:/ / www. reasons. org/ resources/ apologetics/ design. shtml?main)"

Fine-tuned Universe 8

• " Evidence For Design In The Universe. (http:/ / doesgodexist. com/ Charts/EvidenceForDesignInTheUniverse. html)"

• Gerald Schroeder: Fine-turned universe. (http:/ / www. geraldschroeder. com/ tuning. html)• The cosmos is fine-tuned to permit human life (http:/ / www. talkorigins. org/ indexcc/ CI/ CI301. html) at the

talk.origins index to creationist claims.• Interview (http:/ / www. berkeley. edu/ news/ media/ releases/ 2005/ 06/ 17_townes. shtml) with Charles Townes

discussing science and religion.• Home page (http:/ / www. templeton. org/ biochem-finetuning/ purpose. html) of Templeton Foundation project

on fine-tuning.Criticize fine tuning:• Bibliography of online Links to criticisms of the Fine-Tuning Argument. (http:/ / www. infidels. org/ library/

modern/ theism/ design. html#fine) Secular Web.• Ikeda, Michael, and Jefferys, William H., " The Anthropic Principle Does Not Support Supernaturalism. (http:/ /

quasar. as. utexas. edu/ anthropic. html)"• Jefferys, W. H,. and J. O. Berger, " Sharpening Ockham's razor on a Bayesian strop. (http:/ / bayesrules. net/

papers/ ockham. pdf)"• Victor Stenger:

• " Does the Cosmos Show Evidence of Purpose? (http:/ / www. colorado. edu/ philosophy/ vstenger/ Cosmo/anthro. skinq. html)"

• " Is the Universe fine-tuned for us? (http:/ / www. colorado. edu/ philosophy/ vstenger/ Cosmo/ FineTune.pdf)"

• Elliott Sober, " The Design Argument. (http:/ / philosophy. wisc. edu/ sober/ design argument 11 2004. pdf)" Anearlier version appeared in the Blackwell Companion to the Philosophy of Religion (2004).

Anthropic principle 9

Anthropic principleIn physics and cosmology, the anthropic principle is the philosophical argument that observations of the physicaluniverse must be compatible with the conscious life that observes it. Some proponents of the argument reason that itexplains why the universe has the age and the fundamental physical constants necessary to accommodate consciouslife. As a result, they believe that the fact that the universe's fundamental constants are within the narrow rangethought to allow life is not remarkable.The strong anthropic principle as explained by Barrow and Tipler (see variants) states that this is all the case becauseconscious life, in some sense, needed to exist. Critics argue in favor of a weak anthropic principle, which states thatthe universe's fine tuning amounts to selection bias; in an infinite universe, some worlds might evolve conscious life.Douglas Adams used the metaphor of a living puddle examining its own shape, since, to those living creatures, theuniverse may appear to fit them perfectly (while in fact, they simply fit the universe perfectly).

Definition and basisThe principle was formulated as a response to a series of observations that the laws of nature and parameters of theUniverse take on values that are consistent with conditions for life as we know it rather than a set of values thatwould not be consistent with life as observed on Earth. The anthropic principle states that this phenomenon is anecessity because living observers wouldn't be able to exist, and hence, observe the Universe, were these laws andconstants not constituted in this way.The term anthropic in "anthropic principle" has been argued [1] to be a misnomer.[2] While singling out our kind ofcarbon-based life, none of the finely tuned phenomena require human life or demand that carbon-based life developintelligence,[3] [4] however the detection and formulation of this principle, born from a long and laborious history ofscientific observations, trials and errors, studying, ingenuity and inventions of necessary instrumentation, does makethis an intellectual domain exclusive to humans above all other life forms on Earth and beyond, so far as science hasobserved. Both the scientific principles and the intelligence required for their detection are non-material phenomenaand transcend carbon-based life forms which said non-material phenomena give rise to in the first place through theobserved scientific principles and laws governing them moment by moment.The anthropic principle has given rise to some confusion and controversy, partly because the phrase has been appliedto several distinct ideas. All versions of the principle have been accused of discouraging the search for a deeperphysical understanding of the universe. Those attempting to explain the anthropic principle often invoke ideas ofmultiple universes or an intelligent designer,[5] both controversial and criticized for being untestable and thereforecritics of the anthropic principle may point out that the anthropic principle is more of a philosophical concept, not ascientific one. One way to bypass the controversy is to emphasize the weak anthropic principle: "...conditions thatare observed in the universe must allow the observer to exist.".[6] In mathematics and philosophy, the weak form of astatement is one which is "easier" to support, e.g. it makes fewer claims of substance. Even critics of the weakanthropic principle recognize that it is a tautology or truism.[7] However, building up other substantive argumentsbased on a tautological foundation is problematic. Stronger variants of the anthropic principle are not tautologies andmake substantive claims which may be considered controversial by some.

Anthropic coincidencesIn 1961, Robert Dicke noted that the age of the universe, as seen by living observers, cannot be random.[8] Instead, biological factors constrain the universe to be more or less in a "golden age," neither too young nor too old.[9] If the universe were one tenth as old as its present age, there would not have been sufficient time to build up appreciable levels of metallicity (levels of elements besides hydrogen and helium) especially carbon, by nucleosynthesis. Small rocky planets did not yet exist. If the universe were 10 times older than it actually is, most stars would be too old to

Anthropic principle 10

remain on the main sequence and would have turned into white dwarfs, aside from the dimmest red dwarfs, andstable planetary systems would have already come to an end. Thus Dicke explained away the rough coincidencebetween large dimensionless numbers constructed from the constants of physics and the age of the universe, acoincidence which had inspired Dirac's varying-G theory.Dicke later reasoned that the density of matter in the universe must be almost exactly the critical density needed toprevent the Big Crunch (the "Dicke coincidences" argument). The most recent measurements may suggest that theobserved density of baryonic matter, and some theoretical predictions of the amount of dark matter account for about30% of this critical density, with the rest contributed by a cosmological constant. Steven Weinberg[10] gave ananthropic explanation for this fact: he noted that the cosmological constant has a remarkably low value, some 120orders of magnitude smaller than the value particle physics predicts (this has been described as the "worst predictionin physics").[11] However, if the cosmological constant were more than about 10 times its observed value, theuniverse would suffer catastrophic inflation, which would preclude the formation of stars, and hence life.The observed values of the dimensionless physical constants (such as the fine-structure constant) governing the fourfundamental interactions are balanced as if fine-tuned to permit the formation of commonly found matter andsubsequently the emergence of life. A slight increase in the strong nuclear force would bind the dineutron and thediproton, and nuclear fusion would have converted all hydrogen in the early universe to helium. Water and thelong-lived stable stars essential for the emergence of life would not exist. More generally, small changes in therelative strengths of the four fundamental interactions can greatly affect the universe's age, structure, and capacity forlife.

OriginThe phrase "anthropic principle" first appeared in Brandon Carter's contribution to a 1973 Kraków symposiumhonouring Copernicus's 500th birthday. Carter, a theoretical astrophysicist, articulated the Anthropic Principle inreaction to the Copernican Principle, which states that humans do not occupy a privileged position in the Universe.As Carter said: "Although our situation is not necessarily central, it is inevitably privileged to some extent."[12]

Specifically, Carter disagreed with using the Copernican principle to justify the Perfect Cosmological Principle,which states that all large regions and times in the universe must be statistically identical. The latter principleunderlay the steady-state theory, which had recently been falsified by the 1965 discovery of the cosmic microwavebackground radiation. This discovery was unequivocal evidence that the universe has changed radically over time(for example, via the Big Bang).Carter defined two forms of the Anthropic Principle, a "weak" one which referred only to anthropic selection ofprivileged spacetime locations in the universe, and a more controversial "strong" form which addressed the values ofthe fundamental constants of physics.Roger Penrose explained the weak form as follows:

"The argument can be used to explain why the conditions happen to be just right for the existence of(intelligent) life on the earth at the present time. For if they were not just right, then we should not have foundourselves to be here now, but somewhere else, at some other appropriate time. This principle was used veryeffectively by Brandon Carter and Robert Dicke to resolve an issue that had puzzled physicists for a goodmany years. The issue concerned various striking numerical relations that are observed to hold between thephysical constants (the gravitational constant, the mass of the proton, the age of the universe, etc.). A puzzlingaspect of this was that some of the relations hold only at the present epoch in the earth's history, so we appear,coincidentally, to be living at a very special time (give or take a few million years!). This was later explained,by Carter and Dicke, by the fact that this epoch coincided with the lifetime of what are called main-sequencestars, such as the sun. At any other epoch, so the argument ran, there would be no intelligent life around inorder to measure the physical constants in question — so the coincidence had to hold, simply because therewould be intelligent life around only at the particular time that the coincidence did hold!"

Anthropic principle 11

—The Emperor's New Mind, Chapter 10

One reason this is plausible is that there are many other places and times in which we can imagine finding ourselves.But when applying the strong principle, we only have one Universe, with one set of fundamental parameters, so whatexactly is the point being made? Carter offers two possibilities: First, we can use our own existence to make"predictions" about the parameters. But second, "as a last resort", we can convert these predictions into explanationsby assuming that there is more than one Universe, in fact a large and possibly infinite collection of universes,something that is now called a multiverse ("world ensemble" was Carter's term), in which the parameters (andperhaps the laws of physics) vary across universes. The strong principle then becomes an example of a selectioneffect, exactly analogous to the weak principle. Postulating a multiverse is certainly a radical step, but taking it couldprovide at least a partial answer to a question which had seemed to be out of the reach of normal science: "why dothe fundamental laws of physics take the particular form we observe and not another?"Since Carter's 1973 paper, the term "Anthropic Principle" has been extended to cover a number of ideas which differin important ways from those he espoused. Particular confusion was caused in 1986 by the book The AnthropicCosmological Principle by John D. Barrow and Frank Tipler,[13] published that year which distinguished between"weak" and "strong" anthropic principle in a way very different from Carter's, as discussed in the next section.Carter was not the first to invoke some form of the anthropic principle. In fact, the evolutionary biologist AlfredRussel Wallace anticipated the anthropic principle as long ago as 1904: "Such a vast and complex universe as thatwhich we know exists around us, may have been absolutely required ... in order to produce a world that should beprecisely adapted in every detail for the orderly development of life culminating in man."[14] In 1957, Robert Dickewrote: "The age of the Universe 'now' is not random but conditioned by biological factors ... [changes in the valuesof the fundamental constants of physics] would preclude the existence of man to consider the problem."[15]

VariantsWeak anthropic principle (WAP) (Carter): "we must be prepared to take account of the fact that our location in theuniverse is necessarily privileged to the extent of being compatible with our existence as observers."Note that for Carter, "location" refers to our location in time as well as space.Strong anthropic principle (SAP) (Carter): "the Universe (and hence the fundamental parameters on which itdepends) must be such as to admit the creation of observers within it at some stage. To paraphrase Descartes, cogitoergo mundus talis est."The Latin tag ("I think, therefore the world is such [as it is]") makes it clear that "must" indicates a deduction fromthe fact of our existence; the statement is thus a truism.In their 1986 book, The Anthropic Cosmological Principle, John Barrow and Frank Tipler depart from Carter anddefine the WAP and SAP as follows:[16] [17]

Weak anthropic principle (WAP) (Barrow and Tipler): "The observed values of all physical and cosmologicalquantities are not equally probable but they take on values restricted by the requirement that there exist sites wherecarbon-based life can evolve and by the requirements that the Universe be old enough for it to have already doneso."[18]

Unlike Carter they restrict the principle to carbon-based life, rather than just "observers." A more importantdifference is that they apply the WAP to the fundamental physical constants, such as the fine structure constant, thenumber of spacetime dimensions, and the cosmological constant —, topics that fall under Carter's SAP.Strong anthropic principle (SAP) (Barrow and Tipler): "The Universe must have those properties which allow lifeto develop within it at some stage in its history."[19]

This looks very similar to Carter's SAP, but unlike the case with Carter's SAP, the "must" is an imperative, as shownby the following three possible elaborations of the SAP, each proposed by Barrow and Tipler:[20]

Anthropic principle 12

• "There exists one possible Universe 'designed' with the goal of generating and sustaining 'observers.'"This can be seen as simply the classic design argument restated in the garb of contemporary cosmology. It impliesthat the purpose of the universe is to give rise to intelligent life, with the laws of nature and their fundamentalphysical constants set to ensure that life as we know it will emerge and evolve.

• "Observers are necessary to bring the Universe into being."Barrow and Tipler believe that this is a valid conclusion from quantum mechanics, as John Archibald Wheeler hassuggested, especially via his participatory universe and Participatory Anthropic Principle (PAP).

• "An ensemble of other different universes is necessary for the existence of our Universe."By contrast, Carter merely says that an ensemble of universes is necessary for the SAP to count as an explanation.

Modified anthropic principle (MAP) (Schmidhuber): The 'problem' of existence is only relevant to a speciescapable of formulating the question. Prior to homo sapiens' intellectual evolution to the point where the nature of theobserved universe - and humans' place within same - spawned deep inquiry into its origins, the 'problem' simply didnot exist.[21]

The philosophers John Leslie[22] and Nick Bostrom[23] reject the Barrow and Tipler SAP as a fundamentalmisreading of Carter. For Bostrom, Carter's anthropic principle just warns us to make allowance for anthropic bias,that is, the bias created by anthropic selection effects (which Bostrom calls "observation" selection effects) — thenecessity for observers to exist in order to get a result. He writes:

"Many 'anthropic principles' are simply confused. Some, especially those drawing inspiration from BrandonCarter's seminal papers, are sound, but... they are too weak to do any real scientific work. In particular, I arguethat existing methodology does not permit any observational consequences to be derived from contemporarycosmological theories, though these theories quite plainly can be and are being tested empirically byastronomers. What is needed to bridge this methodological gap is a more adequate formulation of howobservation selection effects are to be taken into account."—Anthropic Bias, Introduction., [24]

Strong self-sampling assumption (SSSA) (Bostrom): "Each observer-moment should reason as if it were randomlyselected from the class of all observer-moments in its reference class."Analysing an observer's experience into a sequence of "observer-moments" helps avoid certain paradoxes; but themain ambiguity is the selection of the appropriate "reference class": for Carter's WAP this might correspond to allreal or potential observer-moments in our universe; for the SAP, to all in the multiverse. Bostrom's mathematicaldevelopment shows that choosing either too broad or too narrow a reference class leads to counter-intuitive results,but he is not able to prescribe an ideal choice.According to Jürgen Schmidhuber, the anthropic principle essentially just says that the conditional probability offinding yourself in a universe compatible with your existence is always 1. It does not allow for any additionalnontrivial predictions such as "gravity won't change tomorrow." To gain more predictive power, additionalassumptions on the prior distribution of alternative universes are necessary.[21] [25]

Playwright and novelist Michael Frayn describes a form of the Strong Anthropic Principle in his 2006 book TheHuman Touch, which explores what he characterises as "the central oddity of the Universe":

"It's this simple paradox. The Universe is very old and very large. Humankind, by comparison, is only a tinydisturbance in one small corner of it - and a very recent one. Yet the universe is only very large and very oldbecause we are here to say it is... And yet, of course, we all know perfectly well that it is what it is whether weare here or not."—[26]

Anthropic principle 13

Character of anthropic reasoningCarter chose to focus on a tautological aspect of his ideas, which has resulted in much confusion. In fact, anthropicreasoning interests scientists because of something that is only implicit in the above formal definitions, namely thatwe should give serious consideration to there being other universes with different values of the "fundamentalparameters" — that is, the dimensionless physical constants and initial conditions for the Big Bang. Carter and othershave argued that life as we know it would not be possible in most such universes. In other words, the universe we arein is fine tuned to permit life. Collins & Hawking (1973) characterized Carter's then-unpublished big idea as thepostulate that "there is not one universe but a whole infinite ensemble of universes with all possible initialconditions".[27] If this is granted, the anthropic principle provides a plausible explanation for the fine tuning of ouruniverse: the "typical" universe is not fine-tuned, but given enough universes, a small fraction thereof will be capableof supporting intelligent life. Ours must be one of these, and so the observed fine tuning should be no cause forwonder.But how seriously can we take the multiverse? And which specific multiverse should we assume? — this questionmust be answered before any quantitative anthropic predictions can be made. Although philosophers have discussedrelated concepts for centuries, in the early 1970s the only genuine physical theory yielding a multiverse of sorts wasthe many worlds interpretation of quantum mechanics. This would allow variation in initial conditions, but not in thetruly fundamental constants. Since that time a number of mechanisms for producing a multiverse have beensuggested: see the review by Max Tegmark.[28] An important development in the 1980s was the combination ofinflation theory with the hypothesis that some parameters are determined by symmetry breaking in the earlyuniverse, which allows parameters previously thought of as "fundamental constants" to vary over very largedistances, thus eroding the distinction between Carter's weak and strong principles. At the beginning of the 21stcentury, the string landscape emerged as a mechanism for varying essentially all the constants, including the numberof spatial dimensions.[29]

The anthropic idea that fundamental parameters are selected from a multitude of different possibilities (each actual insome universe or other) contrasts with the traditional hope of physicists for a theory of everything having no freeparameters: as Einstein said, "What really interests me is whether God had any choice in the creation of the world."Quite recently, proponents of the leading candidate for a "theory of everything", string theory, proclaimed "the endof the anthropic principle"[30] since there would be no free parameters to select. Ironically, string theory now seemsto offer no hope of predicting fundamental parameters, and now some who advocate it invoke the anthropic principleas well (see below).The modern form of a design argument is put forth by Intelligent design. Proponents of intelligent design often citethe fine-tuning observations that (in part) preceded the formulation of the anthropic principle by Carter as a proof ofan intelligent designer. Opponents of intelligent design are not limited to those who hypothesize that other universesexist; they may also argue, anti-anthropically, that the universe is less fine-tuned than often claimed, or thataccepting fine tuning as a brute fact is less astonishing than the idea of an intelligent creator. Furthermore, evenaccepting fine tuning, Sober (2005)[31] and Ikeda and Jefferys,[32] [33] argue that the Anthropic Principle asconventionally stated actually undermines intelligent design; see fine-tuned universe.Paul Davies's book The Goldilocks Enigma (2006) reviews the current state of the fine tuning debate in detail, andconcludes by enumerating the following responses to that debate:1. The absurd universe

Our universe just happens to be the way it is.2. The unique universe

There is a deep underlying unity in physics which necessitates the universe being the way it is. Some Theoryof Everything will explain why the various features of the Universe must have exactly the values that we see.

3. The multiverse

Anthropic principle 14

Multiple Universes exist, having all possible combinations of characteristics, and we inevitably find ourselveswithin a Universe that allows us to exist.

4. CreationismA creator designed the Universe with the purpose of supporting complexity and the emergence of Intelligence.

5. The life principleThere is an underlying principle that constrains the universe to evolve towards life and mind.

6. The self-explaining universeA closed explanatory or causal loop: "perhaps only universes with a capacity for consciousness can exist."This is Wheeler's Participatory Anthropic Principle (PAP).

7. The fake universeWe live inside a virtual reality simulation.

Omitted here is Lee Smolin's model of cosmological natural selection, also known as "fecund universes," whichproposes that universes have "offspring" which are more plentiful if they resemble our universe. Also see Gardner(2005).[34]

Clearly each of these hypotheses resolve some aspects of the puzzle, while leaving others unanswered. Followers ofCarter would admit only option 3 as an anthropic explanation, whereas 3 through 6 are covered by different versionsof Barrow and Tipler's SAP (which would also include 7 if it is considered a variant of 4, as in Tipler 1994).The anthropic principle, at least as Carter conceived it, can be applied on scales much smaller than the wholeuniverse. For example, Carter (1983)[35] inverted the usual line of reasoning and pointed out that when interpretingthe evolutionary record, one must take into account cosmological and astrophysical considerations. With this inmind, Carter concluded that given the best estimates of the age of the universe, the evolutionary chain culminating inHomo sapiens probably admits only one or two low probability links. Antonio Feoli and Salvatore Rampone disputethis conclusion, arguing instead that the estimated size of our universe and the number of planets in it allows for ahigher bound, so that there is no need to invoke intelligent design to explain evolution. [36]

Observational evidenceNo possible observational evidence bears on Carter's WAP, as it is merely advice to the scientist and asserts nothingdebatable. The obvious test of Barrow's SAP, which says that the Universe is "required" to support life, is to findevidence of life in universes other than ours. However, as any other universe is, by definition, unobservable(otherwise it would be part of our universe), this test cannot be carried out, and Barrow's SAP is untestable.Philosopher John Leslie[37] states that the Carter SAP (with multiverse) predicts the following:• Physical theory will evolve so as to strengthen the hypothesis that early phase transitions occur probabilistically

rather than deterministically, in which case there will be no deep physical reason for the values of fundamentalconstants;

• Various theories for generating multiple universes will prove robust;• Evidence that the universe is fine tuned will continue to accumulate;• No life with a non-carbon chemistry will be discovered;• Mathematical studies of galaxy formation will confirm that it is sensitive to the rate of expansion of the universe.Hogan[38] has emphasised that it would be very strange if all fundamental constants were strictly determined, sincethis would leave us with no ready explanation for apparent fine tuning. In fact we might have to resort to somethingakin to Barrow and Tipler's SAP: there would be no option for such a universe not to support life.Probabilistic predictions of parameter values can be made given: (i) a particular multiverse with a "measure", i.e. a well defined "density of universes" (so, for parameter X, one can calculate the prior probability P(X0) dX that X is in the range X0 < X < X0 + dX), and (ii) an estimate of the number of observers in each universe, N(X) (e.g., this might be taken as proportional to the

Anthropic principle 15

number of stars in the universe). The probability of observing value X is then proportional to N(X) P(X). (A more sophisticated analysis is that of NickBostrom.)[39] A generic feature of an analysis of this nature is that the expected values of the fundamental physicalconstants should not be "over-tuned," i.e. if there is some perfectly tuned predicted value (e.g. zero), the observedvalue need be no closer to that predicted value than what is required to make life possible. The small but finite valueof the cosmological constant can be regarded as a successful prediction in this sense.One thing that would not count as evidence for the Anthropic Principle is evidence that the Earth or the solar systemoccupied a privileged position in the universe, in violation of the Copernican principle (for possible counterevidenceto this principle, see Copernican principle), unless there was some reason to think that that position was a necessarycondition for our existence as observers.

Applications of the principle

The nucleosynthesis of carbon-12Fred Hoyle may have invoked anthropic reasoning to predict an astrophysical phenomenon. He is said to havereasoned from the prevalence on earth of life forms whose chemistry was based on carbon-12 atoms, that there mustbe an undiscovered resonance in the carbon-12 nucleus facilitating its synthesis in stellar interiors via the triple-alphaprocess. He then calculated the energy of this undiscovered resonance to be 7.6 million electron-volts.[40] [41] WillieFowler's research group soon found this resonance, and its measured energy was close to Hoyle's prediction.However, a recently released paper argues that Hoyle did not use anthropic reasoning to make this prediction.[42]

Cosmic inflationDon Page criticized the entire theory of cosmic inflation as follows.[43] He emphasized that initial conditions whichmade possible a thermodynamic arrow of time in a universe with a Big Bang origin, must include the assumptionthat at the initial singularity, the entropy of the universe was low and therefore extremely improbable. Paul Daviesrebutted this criticism by invoking an inflationary version of the anthropic principle.[44] While Davies accepted thepremise that the initial state of the visible Universe (which filled a microscopic amount of space before inflating) hadto possess a very low entropy value — due to random quantum fluctuations — to account for the observedthermodynamic arrow of time, he deemed this fact an advantage for the theory. That the tiny patch of space fromwhich our observable Universe grew had to be extremely orderly, to allow the post-inflation universe to have anarrow of time, makes it unnecessary to adopt any "ad hoc" hypotheses about the initial entropy state, hypothesesother Big Bang theories require.

String theoryString theory predicts a large number of possible universes, called the "backgrounds" or "vacua." The set of thesevacua is often called the "multiverse" or "anthropic landscape" or "string landscape." Leonard Susskind has arguedthat the existence of a large number of vacua puts anthropic reasoning on firm ground: only universes whoseproperties are such as to allow observers to exist are observed, while a possibly much larger set of universes lackingsuch properties go unnoticed.Steven Weinberg[45] believes the Anthropic Principle may be appropriated by cosmologists committed to nontheism,and refers to that Principle as a "turning point" in modern science because applying it to the string landscape "...mayexplain how the constants of nature that we observe can take values suitable for life without being fine-tuned by abenevolent creator." Others, most notably David Gross but also Lubos Motl, Peter Woit, and Lee Smolin, argue thatthis is not predictive. Max Tegmark,[46] Mario Livio, and Martin Rees[47] argue that only some aspects of a physicaltheory need be observable and/or testable for the theory to be accepted, and that many well-accepted theories are farfrom completely testable at present.

Anthropic principle 16

Jürgen Schmidhuber (2000–2002) points out that Ray Solomonoff's theory of universal inductive inference and itsextensions already provide a framework for maximizing our confidence in any theory, given a limited sequence ofphysical observations, and some prior distribution on the set of possible explanations of the universe.

Ice densityWhen water freezes into ice, the ice floats because ice is less dense than liquid water. This is one possible example ofthe anthropic principle, because if ice did not float, it might have been difficult or impossible for living organisms tohave existed in water; without the insulating properties of a top ice layer, lakes and ponds would tend to freeze solidand thaw very little during warmer periods. This principle has been criticized as neglecting the existence of thetropical zone and other warmer climates.Ice is unusual in that it is approximately 9% less dense than liquid water. Water is the only known non-metallicsubstance to expand when it freezes. The density of ice is 0.9167 g/cm3 at 0°C, whereas water has a density of0.9998 g/cm3 at the same temperature. Liquid water is densest, essentially 1.00 g/cm3, at 4°C and becomes lessdense as the water molecules begin to form the hexagonal crystals[48] of ice as the freezing point is reached. This isdue to hydrogen bonding dominating the intermolecular forces, which results in a packing of molecules less compactin the solid.

The Anthropic Cosmological PrincipleThe most thorough extant study of the anthropic principle is the book The Anthropic Cosmological Principle by JohnD. Barrow, a cosmologist, and Frank J. Tipler, a mathematical physicist. This book sets out in great detail the manyknown anthropic coincidences and constraints, including many found by its authors. While the book is primarily awork of theoretical astrophysics, it also touches on quantum physics, chemistry, and earth science. An entire chapterargues that homo sapiens is, with high probability, the only intelligent species in the Milky Way.The book begins with an extensive review of many topics in the history of ideas the authors deem relevant to theanthropic principle, because the authors believe that principle has important antecedents in the notions of teleologyand intelligent design. They discuss the writings of Fichte, Hegel, Bergson, and Alfred North Whitehead, and theOmega Point cosmology of Teilhard de Chardin. Barrow and Tipler carefully distinguish teleological reasoning fromeutaxiological reasoning; the former asserts that order must have a consequent purpose; the latter asserts moremodestly that order must have a planned cause. They attribute this important but nearly always overlookeddistinction to an obscure 1883 book by L. E. Hicks.[49]

Seeing little sense in a principle requiring intelligent life to emerge while remaining indifferent to the possibility ofits eventual extinction, Barrow and Tipler propose the:

"Final anthropic principle (FAP): Intelligent information-processing must come into existence in the Universe,and, once it comes into existence, it will never die out."—[50]

Barrow and Tipler submit that the FAP is both a valid physical statement and "closely connected with moral values."FAP places strong constraints on the structure of the universe, constraints developed further in Tipler's The Physicsof Immortality.[51] One such constraint is that the universe must end in a big crunch, which seems unlikely in view ofthe tentative conclusions drawn since 1998 about dark energy, based on observations of very distant supernovas.In his review[52] of Barrow and Tipler, Martin Gardner ridiculed the FAP by quoting the last two sentences of theirbook as defining a Completely Ridiculous Anthropic Principle (CRAP):

"At the instant the Omega Point is reached, life will have gained control of all matter and forces not only in asingle universe, but in all universes whose existence is logically possible; life will have spread into all spatialregions in all universes which could logically exist, and will have stored an infinite amount of information,including all bits of knowledge which it is logically possible to know. And this is the end."

Anthropic principle 17

—[53]

CriticismsCarter himself[54] has frequently regretted his own choice of the word "anthropic," because it conveys the misleadingimpression that the principle involves humans specifically, rather than intelligent observers in general. Others[55]

have criticised the word "principle" as being too grandiose to describe straightforward applications of selectioneffects.A common criticism of Carter's SAP is that it is an easy deus ex machina which discourages searches for physicalexplanations. To quote Penrose again: "it tends to be invoked by theorists whenever they do not have a good enoughtheory to explain the observed facts."[56]

Carter's SAP and Barrow and Tipler's WAP have been dismissed as truisms or tautologies, that is, statements truesolely by virtue of their logical form (the conclusion is identical to the premise) and not because a substantive claimis made and supported by observation of reality. As such, they are criticized as an elaborate way of saying "if thingswere different, they would be different," which is a valid statement, but does not make a claim of some factualalternative over another. The anthropic principles implicitly posit that our ability to ponder cosmology at all iscontingent on one or more fundamental physical constants having numerical values falling within quite a narrowrange, and this is not a tautology; nor is postulating a multiverse. Moreover, working out the consequences of achange in the fundamental constants for the existence of our species is far from trivial, and, as we have seen, can leadto quite unexpected constraints on physical theory. This reasoning does, however, demonstrate that carbon-based lifeis impossible under these altered fundamental parameters.Critics of the Barrow and Tipler SAP claim that it is neither testable nor falsifiable, and thus is not a scientificstatement but rather a philosophical one. The same criticism has been leveled against the hypothesis of a multiverse,although some argue that it does make falsifiable predictions. A modified version of this criticism is that weunderstand so little about the emergence of life, especially intelligent life, that it is effectively impossible to calculatethe number of observers in each universe. Also, the prior distribution of universes as a function of the fundamentalconstants is easily modified to get any desired result.[57]

Many criticisms focus on versions of the Strong Anthropic Principle, such as Barrett and Tipler's anthropiccosmological principle, which are teleological notions that tend to describe the existence of life as a necessaryprerequisite for the observable constants of physics. In a lecture titled "The Confusion of Cause and Effect in BadScience," the paleophysicist Caroline Miller said:[58]

"The Anthropic Principle is based on the underlying belief that the universe was created for our benefit.Unfortunately for its adherents, all of the reality-based evidence at our disposal contradicts this belief. In anonanthropocentric universe, there is no need for multiple universes or supernatural entities to explain life aswe know it."

Similarly, Stephen Jay Gould,[59] [60] Michael Shermer[61] and others claim that the stronger versions of theAnthropic Principle seem to reverse known causes and effects. Gould compared the claim that the universe isfine-tuned for the benefit of our kind of life to saying that sausages were made long and narrow so that they could fitinto modern hotdog buns, or saying that ships had been invented to house barnacles. These critics cite the vastphysical, fossil, genetic, and other biological evidence consistent with life having been fine-tuned through naturalselection to adapt to the physical and geophysical environment in which life exists. Life appears to have adapted tophysics, and not vice versa.Some applications of the anthropic principle have been criticized as an argument by lack of imagination, for tacitly assuming that carbon compounds and water are the only possible chemistry of life (sometimes called "carbon chauvinism", see also alternative biochemistry).[62] The range of fundamental physical constants consistent with the evolution of carbon-based life may also be wider than those who advocate a fine tuned universe have argued.[63] For

Anthropic principle 18

instance, Harnik et al.[64] propose a weakless universe in which the weak nuclear force is eliminated. They show thatthis has no significant effect on the other fundamental interactions, provided some adjustments are made in howthose interactions work. However, if some of the fine-tuned details of our universe were violated, that would rule outcomplex structures of any kind — stars, planets, galaxies, etc.Lee Smolin has offered a theory designed to improve on the lack of imagination that anthropic principles have beenaccused of. He puts forth his fecund universes theory, which assumes universes have "offspring" through the creationof black holes, and that these offspring universes have values of physical constants that depend on these of themother universe.[65] Some versions of the anthropic principle are only interesting if the range of physical constantsthat allow certain kinds of life are unlikely in a landscape of possible universes. But Lee Smolin assumes thatconditions for carbon based life are similar to conditions for black hole creation, which would change the a prioridistribution of universes such that universes containing life would be likely. In [66] the string theorist LeonardSusskind disagrees about some assumptions in Lee Smolin's theory, while Smolin defends his theory.The philosophers of cosmology John Earman,[67] Ernan McMullin [68] and Jesús Mosterín contend that "in its weakversion, the anthropic principle is a mere tautology, which does not allow us to explain anything or to predictanything that we did not already know. In its strong version, it is a gratuitous speculation".[69] A further criticism byMosterín concerns the flawed "anthropic" inference from the assumption of an infinity of worlds to the existence ofone like ours:

“The suggestion that an infinity of objects characterized by certain numbers or properties implies the existenceamong them of objects with any combination of those numbers or characteristics [...] is mistaken. An infinitydoes not imply at all that any arrangement is present or repeated. [...] The assumption that all possible worldsare realized in an infinite universe is equivalent to the assertion that any infinite set of numbers contains allnumbers (or at least all Gödel numbers of the [defining] sequences), which is obviously false.”

Footnotes[1] Mosterín (2005) pp. 12 http:/ / philsci-archive. pitt. edu/ 1658/ "[2] "anthropic" means "of or pertaining to mankind or humans"[3] The Anthropic Principle (http:/ / www. colorado. edu/ philosophy/ vstenger/ Cosmo/ ant_encyc. pdf), Victor J. Stenger[4] Anthropic Bias (http:/ / books. google. co. uk/ books?id=TZ5FLwnCTMAC& client=firefox-a), Nick Bostrom, p.6[5] The Limitations of Scientific Truth: Why Science Can't Answer Life's Questions - By Nigel Brush (2005), ISBN 978-0-8254-2253-9 pp. 215[6] Merriam-Webster Online Dictionary (http:/ / www. merriam-webster. com/ dictionary/ anthropic principle)[7] The Limitations of Scientific Truth: Why Science Can't Answer Life's Questions - By Nigel Brush (2005), ISBN 978-0-8254-2253-9 pp. 217[8] Dicke, R. H. (1961). "Dirac's Cosmology and Mach's Principle". Nature 192 (4801): 440–441. Bibcode 1961Natur.192..440D.

doi:10.1038/192440a0.[9] Davies, P. (2006). The Goldilocks Enigma. Allen Lane. ISBN 0713998830.[10] Weinberg, S. (1987). "Anthropic bound on the cosmological constant". Physical Review Letters 59 (22): 2607–2610.

Bibcode 1987PhRvL..59.2607W. doi:10.1103/PhysRevLett.59.2607. PMID 10035596.[11] http:/ / www. newscientist. com/ blog/ space/ 2007/ 02/ physicists-debate-nature-of-space-time. html[12] Carter, B. (1974). "Large Number Coincidences and the Anthropic Principle in Cosmology". IAU Symposium 63: Confrontation of

Cosmological Theories with Observational Data. Dordrecht: Reidel. pp. 291–298.[13] [ Edit this reference (http:/ / en. wikipedia. org/ w/ index. php?title=Template:BarrowTipler1986& action=edit)]

Barrow, John D.; Tipler, Frank J. (19 May 1988). The Anthropic Cosmological Principle (http:/ / books. google.com/ books?id=uSykSbXklWEC& printsec=frontcover). foreword by John A. Wheeler. Oxford: Oxford UniversityPress. ISBN 9780192821478. LC 87-28148 (http:/ / lccn. loc. gov/ 87028148). . Retrieved 31 December 2009.[14] Wallace, A. R. (1904). Man's place in the universe: a study of the results of scientific research in relation to the unity or plurality of worlds,

4th ed. London: George Bell & Sons. pp. 256–7.[15] Dicke, R. H. (1957). "Gravitation without a Principle of Equivalence". Reviews of Modern Physics 29: 363–376.

Bibcode 1957RvMP...29..363D. doi:10.1103/RevModPhys.29.363.[16] Barrow, John D. (1997). "Anthropic Definitions". Quarterly Journal of the Royal Astronomical Society 24: 146–53. arXiv:gr-qc/9702052.

Bibcode 1997CQGra..14L..69T. doi:10.1088/0264-9381/14/4/002.[17] Barrow & Tipler's definitions are quoted verbatim at Genesis of Eden Diversity Encyclopedia. (http:/ / www. dhushara. com/ book/

quantcos/ anth/ anth. htm)

Anthropic principle 19

[18] Barrow and Tipler 1986: 16.[19] Barrow and Tipler 1986: 21.[20] Barrow and Tipler 1986: 22.[21] Jürgen Schmidhuber, 2000, " Algorithmic theories of everything. (http:/ / arxiv. org/ abs/ quant-ph/ 0011122)"[22] Leslie, J. (1986). "Probabilistic Phase Transitions and the Anthropic Principle" (http:/ / adsabs. harvard. edu/ cgi-bin/

nph-bib_query?bibcode=1986LIACo. . 26. . 439L). Origin and Early History of the Universe: LIEGE 26. Knudsen. pp. 439–444. .[23] Bostrom, N. (2002). Anthropic Bias: Observation Selection Effects in Science and Philosophy. Routledge. ISBN 0-415-93858-9. 5 chapters

available online. (http:/ / www. anthropic-principle. com/ book/ )[24] Bostrom, N. (2002), op. cit.[25] Jürgen Schmidhuber, 2002, " The Speed Prior: A New Simplicity Measure Yielding Near-Optimal Computable Predictions. (http:/ / www.

idsia. ch/ ~juergen/ speedprior. html)" Proc. 15th Annual Conference on Computational Learning Theory (COLT 2002), Sydney, Australia,Lecture Notes in Artificial Intelligence. Springer: 216-28.

[26] Michael Frayn, The Human Touch. Faber & Faber ISBN 0571232175[27] Collins C. B., Hawking, S. W. (1973). "Why is the universe isotropic?". Astrophysical Journal 180: 317–334.

Bibcode 1973ApJ...180..317C. doi:10.1086/151965.[28] Tegmark, M. (1998). "Is 'the theory of everything' merely the ultimate ensemble theory?". Annals of Physics 270: 1–51.

arXiv:gr-qc/9704009. Bibcode 1998AnPhy.270....1T. doi:10.1006/aphy.1998.5855.[29] Strictly speaking, the number of non-compact dimensions, see String theory.[30] Kane, Gordon L., Perry, Malcolm J., and Zytkow, Anna N. (2002). "The Beginning of the End of the Anthropic Principle". New Astronomy

7: 45–53. arXiv:astro-ph/0001197. Bibcode 2002NewA....7...45K. doi:10.1016/S1384-1076(01)00088-4.[31] Sober, Elliott, 2005, " The Design Argument (http:/ / philosophy. wisc. edu/ sober/ black-da. pdf)" in Mann, W. E., ed., The Blackwell Guide

to the Philosophy of Religion. Blackwell Publishers.[32] Ikeda, M. and Jefferys, W., "The Anthropic Principle Does Not Support Supernaturalism," in The Improbability of God, Michael Martin and

Ricki Monnier, Editors, pp. 150-166. Amherst, N.Y.: Prometheus Press. ISBN 1-59102-381-5[33] Ikeda, M. and Jefferys, W. (2006). Unpublished FAQ " The Anthropic Principle Does Not Support Supernaturalism. (http:/ / quasar. as.

utexas. edu/ anthropic. html)"[34] Gardner, James N., 2005, " The Physical Constants as Biosignature: An anthropic retrodiction of the Selfish Biocosm Hypothesis, (http:/ /

www. kurzweilai. net/ meme/ frame. html?main=/ articles/ art0647. html)" International Journal of Astrobiology.[35] Carter, B. (1983). "The anthropic principle and its implications for biological evolution". Philosophical Transactions of the Royal Society

A310: 347–363. arXiv:gr-qc/9702052. Bibcode 1997CQGra..14L..69T. doi:10.1088/0264-9381/14/4/002.[36] Feoli, A. and Rampone, S. (1999). "Is the Strong Anthropic Principle too weak?". Nuovo Cim. B114: 281–289. arXiv:gr-qc/9812093.

Bibcode 1997CQGra..14L..69T. doi:10.1088/0264-9381/14/4/002.[37] Leslie, J. (1986) op. cit.[38] Hogan, Craig (2000). "Why is the universe just so?". Reviews of Modern Physics 72: 1149–1161. arXiv:astro-ph/9909295.

Bibcode 2000RvMP...72.1149H. doi:10.1103/RevModPhys.72.1149.[39] Bostrom (2002), op. cit.[40] University of Birmingham Life, Bent Chains and the Anthropic Principle (http:/ / www. np. ph. bham. ac. uk/ research/ anthropic. htm)[41] Rev. Mod. Phys. 29 (1957) 547[42] Kragh, Helge (2010) When is a prediction anthropic? Fred Hoyle and the 7.65 MeV carbon resonance. http:/ / philsci-archive. pitt. edu/

5332/[43] Page, D.N. (1983). "Inflation does not explain time asymmetry". Nature 304 (5921): 39. Bibcode 1983Natur.304...39P.

doi:10.1038/304039a0.[44] Davies, P.C.W. (1984). "Inflation to the universe and time asymmetry". Nature 312 (5994): 524. Bibcode 1984Natur.312..524D.

doi:10.1038/312524a0.[45] Weinberg, S. (2007). "Living in the multiverse". In B. Carr (ed). Universe or multiverse?. Cambridge University Press. ISBN 0521848415.

preprint (http:/ / arxiv. org/ abs/ hep-th/ 0511037)[46] Tegmark (1998) op. cit.[47] Livio, M. and Rees, M. J. (2003). "Anthropic reasoning". Science 309 (5737): 1022. Bibcode 2005Sci...309.1022L.

doi:10.1126/science.1111446. PMID 16099967.[48] The word crystal derives from Greek word for frost.[49] Hicks, L. E. (1883). A Critique of Design Arguments. New York: Scribner's.[50] Barrow and Tipler 1986: 23[51] Tipler, F. J. (1994). The Physics of Immortality. DoubleDay. ISBN 0385467982.[52] Gardner, M., "WAP, SAP, PAP, and FAP," The New York Review of Books 23, No. 8 (May 8, 1986): 22-25.[53] Barrow and Tipler 1986: 677[54] e.g. Carter (2004) op. cit.[55] e.g. message from Martin Rees presented at the Kavli-CERCA conference (see video in External links)[56] Penrose, R. (1989). The Emperor's New Mind. Oxford University Press. ISBN 0198519737. Chapter 10.

Anthropic principle 20

[57] Starkman, G. D., Trotta, R. (2006). "Why Anthropic Reasoning Cannot Predict Λ". Physical Review Letters 97 (20): 201301.arXiv:astro-ph/0607227. Bibcode 2006PhRvL..97t1301S. doi:10.1103/PhysRevLett.97.201301. PMID 17155671. See also this news story.(http:/ / www. physorg. com/ news83924839. html)

[58] Miller, Caroline (2006). "The Confusion of Cause and Effect in Bad Science". Lecture at Piffard University.[59] Gould, Stephen Jay (1998). "Clear Thinking in the Sciences". Lectures at Harvard University.[60] Gould, Stephen Jay (2002). Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time.

ISBN 0716730901.[61] Shermer, Michael (2007). Why Darwin Matters. ISBN 0805081216.[62] e.g. Carr, B. J., Rees, M. J. (1979). "The anthropic principle and the structure of the physical world". Nature 278 (5705): 605–612.

Bibcode 1979Natur.278..605C. doi:10.1038/278605a0.[63] Stenger, Victor J (2000). Timeless Reality: Symmetry, Simplicity, and Multiple Universes. Prometheus Books. ISBN 1-57392-859-3.[64] Harnik, R., Kribs, G., Perez, G. (2006). "A Universe without Weak interactions". Physical Review D74: 035006. arXiv:gr-qc/9702052.

Bibcode 1997CQGra..14L..69T. doi:10.1088/0264-9381/14/4/002. preprint (http:/ / arxiv. org/ abs/ hep-ph/ hep-ph/ 0604027)[65] Lee Smolin (2001). Tyson, Neil deGrasse and Soter, Steve. ed. Cosmic Horizons: Astronomy at the Cutting Edge. The New Press.

pp. 148–152. ISBN 978-1565846029.[66] Smolin vs. Susskind: The Anthropic Principle (http:/ / www. edge. org/ 3rd_culture/ smolin_susskind04/ smolin_susskind. html)[67] Earman John (1987). "The SAP also rises: A critical examination of the anthropic principle". American Philosophical Quarterly 24:

307–317.[68] McMullin, Ernan. (1994). "Fine-tuning the universe?" In M. Shale & G. Shields (ed.), Science, Technology, and Religious Ideas, Lanham:

University Press of America.[69] Mosterín, Jesús. (2005). Op. cit.

References• [ Edit this reference (http:/ / en. wikipedia. org/ w/ index. php?title=Template:BarrowTipler1986& action=edit)]

Barrow, John D.; Tipler, Frank J. (19 May 1988). The Anthropic Cosmological Principle (http:/ / books. google.com/ books?id=uSykSbXklWEC& printsec=frontcover). foreword by John A. Wheeler. Oxford: Oxford UniversityPress. ISBN 9780192821478. LC 87-28148 (http:/ / lccn. loc. gov/ 87028148). Retrieved 31 December 2009.• Cirkovic, M. M. (2002). "On the First Anthropic Argument in Astrobiology". Earth, Moon, and Planets 91:

243–254. doi:10.1023/A:1026266630823.• Cirkovic, M. M. (2004). "The Anthropic Principle and the Duration of the Cosmological Past". Astronomical and

Astrophysical Transactions 23: 567–597. arXiv:astro-ph/0505005. Bibcode 2004A&AT...23..567C.doi:10.1080/10556790412331335327.

• Conway Morris, Simon (2003). Life's Solution: Inevitable Humans in a Lonely Universe. Cambridge UniversityPress.

• Craig, William Lane (1987). "Critical review of The Anthropic Cosmological Principle". InternationalPhilosophical Ouarterly 27: 437–47.

• Hawking, Stephen W. (1988). A Brief History of Time. New York: Bantam Books. pp. 174. ISBN 0-553-34614-8.• Stenger, Victor J. (1999), "Anthropic design," The Skeptical Inquirer 23 (August 31, 1999): 40-43• Mosterín, Jesús. (2005). "Anthropic Explanations in Cosmology." In P. Háyek, L. Valdés and D. Westerstahl

(ed.), Logic, Methodology and Philosophy of Science, Proceedings of the 12th International Congress of theLMPS. London: King's College Publications, pp. 441–473. ISBN 1-904987-21-4.

• Taylor, Stuart Ross (1998). Destiny or Chance: Our Solar System and Its Place in the Cosmos. CambridgeUniversity Press. ISBN 0521785219.

• Tegmark, Max (1997). "On the dimensionality of spacetime" (http:/ / space. mit. edu/ home/ tegmark/ dimensions.html). Classical and Quantum Gravity 14: L69–L75. arXiv:gr-qc/9702052. Bibcode 1997CQGra..14L..69T.doi:10.1088/0264-9381/14/4/002. A simple anthropic argument for why there are 3 spatial and 1 temporaldimensions.

• Tipler, F. J. (2003). "Intelligent Life in Cosmology". International Journal of Astrobiology 2: 141–48.Bibcode 2003IJAsB...2..141T. doi:10.1017/S1473550403001526.

• Walker, M. A., and Cirkovic, M. M. (2006). "Anthropic Reasoning, Naturalism and the Contemporary Design Argument". International Studies in the Philosophy of Science 20: 285–307. doi:10.1080/02698590600960945.

Anthropic principle 21

Shows that some of the common criticisms of AP based on its relationship with numerology or the theologicalDesign Argument are wrong.

• Ward, P. D., and Brownlee, D. (2000). Rare Earth: Why Complex Life is Uncommon in the Universe. SpringerVerlag. ISBN 0-387-98701-0..

• Vilenkin, Alex (2006). Many Worlds in One: The Search for Other Universes. Hill and Wang.ISBN 978-0809095230.

External links• Caner, Taslaman, Anthropic Principle and Infinite Universes (http:/ / bigbang. ws/ articles. asp?id=73)• Nick Bostrom: web site (http:/ / www. anthropic-principle. com) devoted to the Anthropic Principle.• Chown, Marcus, Anything Goes, (http:/ / space. mit. edu/ home/ tegmark/ toe_frames. html) New Scientist, 6 June

1998. On Max Tegmark's work.• Stephen Hawking, Steven Weinberg, Alexander Vilenkin, David Gross and Lawrence Krauss: Debate on

Anthropic Reasoning (http:/ / www. phys. cwru. edu/ events/ cerca_video_archive. php) Kavli-CERCAConference Video Archive.

• Tobin, Paul N., 2000, " Is the Universe Fine-Tuned for Life? (http:/ / www. geocities. com/ paulntobin/ finetuned.html)" ( Archived (http:/ / www. webcitation. org/ 5knILnytk) 2009-10-25) A critique of the Anthropic Principlefrom an atheist viewpoint.

• " Anthropic Coincidence (http:/ / www. starlarvae. org/ Star_Larvae_Anthropic_Coincidence. html)"—theanthropic controversy as a segue to Lee Smolin's theory of cosmological natural selection.

• Leonard Susskind and Lee Smolin debate the Anthropic Principle (http:/ / www. edge. org/ 3rd_culture/smolin_susskind04/ smolin_susskind. html).

• debate among scientists on arxiv.org. (http:/ / arXiv. org/ find/ astro-ph/ 1/ OR+ ti:+ AND+ anthropic+ principle+abs:+ AND+ anthropic+ principle/ 0/ 1/ 0/ all/ 0/ 1)

• Evolutionary Probability and Fine Tuning (http:/ / www. epicidiot. com/ evo_cre/ 13cards. htm)• Benevolent Design and the Anthropic Principle (http:/ / www. mathpages. com/ home/ kmath252/ kmath252.

htm) at MathPages• Critical review of "The Privileged Planet" (http:/ / www. epicidiot. com/ evo_cre/ vr_privileged_planet. htm)• The Anthropic Principle (http:/ / www. ipod. org. uk/ reality/ reality_anthropic_principle. asp) - a review.• Berger, Daniel, 2002, " An impertinent resumé of the Anthropic Cosmological Principle. (http:/ / www. bluffton.

edu/ ~bergerd/ essays/ impert. html)" A critique of Barrow & Tipler.• Jürgen Schmidhuber: Papers on algorithmic theories of everything (http:/ / www. idsia. ch/ ~juergen/

computeruniverse. html) and the Anthropic Principle's lack of predictive power.• Paul Davies: Cosmic Jackpot (http:/ / www. wpr. org/ book/ 070415a. html) Interview about the Anthropic

Principle (starts at 40 min), 15 May 2007.

Multiverse 22

MultiverseThe multiverse (or meta-universe, metaverse) is the hypothetical set of multiple possible universes (including thehistorical universe we consistently experience) that together comprise everything that exists: the entirety of space,time, matter, and energy as well as the physical laws and constants that describe them. The term was coined in 1895by the American philosopher and psychologist William James.[1] The various universes within the multiverse aresometimes called parallel universes.The structure of the multiverse, the nature of each universe within it and the relationship between the variousconstituent universes, depend on the specific multiverse hypothesis considered. Multiverses have been hypothesizedin cosmology, physics, astronomy, religion, philosophy, transpersonal psychology and fiction, particularly in sciencefiction and fantasy. In these contexts, parallel universes are also called "alternative universes", "quantum universes","interpenetrating dimensions", "parallel dimensions", "parallel worlds", "alternative realities", "alternativetimelines", and "dimensional planes," among others.

Multiverse hypotheses in physics

Tegmark's classificationCosmologist Max Tegmark has provided a taxonomy of universes beyond the familiar observable universe. Thelevels according to Tegmark's classification are arranged such that subsequent levels can be understood toencompass and expand upon previous levels, and they are briefly described below.[2] [3]

Level I: Beyond our cosmological horizon

A generic prediction of chaotic inflation is an infinite ergodic universe, which, being infinite, must contain Hubblevolumes realizing all initial conditions.Accordingly, an infinite universe will contain an infinite number of Hubble volumes, all having the same physicallaws and physical constants. In regard to configurations such as the distribution of matter, almost all will differ fromour Hubble volume. However, because there are infinitely many, far beyond the cosmological horizon, there willeventually be Hubble volumes with similar, and even identical, configurations. Tegmark estimates that an identicalvolume to ours should be about 1010115 meters away from us (a number larger than a googolplex).[4] [5] Note thatthis estimate seems to assume a uniform distribution of Hubble volume states; in reality, any distribution may betrue, meaning that our particular Hubble volume may, in fact, be unique.

Level II: Universes with different physical constants

"Bubble universes", every disk is a bubbleuniverse (Universe 1 to Universe 6 are differentbubbles, they have physical constants that are

different from our universe), our universe is justone of the bubbles.

In the chaotic inflation theory, a variant of the cosmic inflation theory,the multiverse as a whole is stretching and will continue doing soforever, but some regions of space stop stretching and form distinctbubbles, like gas pockets in a loaf of rising bread. Such bubbles areembryonic level I multiverses. Linde and Vanchurin calculated thenumber of these universes to be on the scale of 101010000000.[6]

Different bubbles may experience different spontaneous symmetrybreaking resulting in different properties such as different physicalconstants.[4]

This level also includes John Archibald Wheeler's oscillatory universetheory and Lee Smolin's fecund universes theory.

Multiverse 23

Level III: Many-worlds interpretation of quantum mechanics

Hugh Everett's many-worlds interpretation (MWI) is one of several mainstream interpretations of quantummechanics. In brief, one aspect of quantum mechanics is that certain observations cannot be predicted absolutely.Instead, there is a range of possible observations each with a different probability. According to the MWI, each ofthese possible observations corresponds to a different universe. Suppose a die is thrown that contains 6 sides and thatthe result corresponds to a quantum mechanics observable. All 6 possible ways the die can fall correspond to 6different universes. (More correctly, in MWI there is only a single universe but after the "split" into "many worlds"these cannot in general interact.)[7]

Tegmark argues that a level III multiverse does not contain more possibilities in the Hubble volume than a level I-IImultiverse. In effect, all the different "worlds" created by "splits" in a level III multiverse with the same physicalconstants can be found in some Hubble volume in a level I multiverse. Tegmark writes that "The only differencebetween Level I and Level III is where your doppelgängers reside. In Level I they live elsewhere in good oldthree-dimensional space. In Level III they live on another quantum branch in infinite-dimensional Hilbert space."Similarly, all level II bubble universes with different physical constants can in effect be found as "worlds" created by"splits" at the moment of spontaneous symmetry breaking in a level III multiverse.[4]

Related to the many-worlds idea are Richard Feynman's multiple histories interpretation and H. Dieter Zeh'smany-minds interpretation.

Level IV: Ultimate Ensemble

The Ultimate Ensemble hypothesis of Tegmark himself. This level considers equally real all universes that can bedescribed by different mathematical structures. This does not include different low-energy physical laws not of ourobservable universe. Tegmark writes that "abstract mathematics is so general that any Theory Of Everything (TOE)that is definable in purely formal terms (independent of vague human terminology) is also a mathematical structure.For instance, a TOE involving a set of different types of entities (denoted by words, say) and relations between them(denoted by additional words) is nothing but what mathematicians call a set-theoretical model, and one can generallyfind a formal system that it is a model of." He argues this "implies that any conceivable parallel universe theory canbe described at Level IV" and "subsumes all other ensembles, therefore brings closure to the hierarchy ofmultiverses, and there cannot be say a Level V."[8]

Jürgen Schmidhuber, however, says the "set of mathematical structures" is not even well-defined, and admits onlyuniverse representations describable by constructive mathematics, that is, computer programs. He explicitly includesuniverse representations describable by non-halting programs whose output bits converge after finite time, althoughthe convergence time itself may not be predictable by a halting program, due to Kurt Gödel's limitations.[9] [10] [11]

He also explicitly discusses the more restricted ensemble of quickly computable universes.[12]

Cyclic theoriesIn several theories there is a series of infinite, self-sustaining cycles (for example: an eternity of Big Bang-Bigcrunches).

M-theoryA multiverse of a somewhat different kind has been envisaged within the multi-dimensional extension of stringtheory known as M-theory, also known as Membrane Theory.[13] In M-theory our universe and others are created bycollisions between p-branes in a space with 11 and 26 dimensions (the number of dimensions depends on thechirality of the observer);[14] [15] each universe takes the form of a D-brane.[14] [15] Objects in each universe areessentially confined to the D-brane of their universe, but may be able to interact with other universes via gravity, aforce which is not restricted to D-branes.[16] This is unlike the universes in the "quantum multiverse", but bothconcepts can operate at the same time.

Multiverse 24

Anthropic principleThe concept of other universes has been proposed to explain why our universe seems to be fine-tuned for consciouslife as we experience it. If there were a large number (possibly infinite) of different physical laws (or fundamentalconstants) in as many universes, some of these would have laws that were suitable for stars, planets and life to exist.The weak anthropic principle could then be applied to conclude that we would only consciously exist in thoseuniverses which were finely tuned for our conscious existence. Thus, while the probability might be extremely smallthat there is life in most of the universes, this scarcity of life-supporting universes does not imply intelligent designas the only explanation of our existence.

Criticisms

Non-scientific claims

Critics claim that many of these theories lack empirical testability, and without hard physical evidence areunfalsifiable; outside the methodology of scientific investigation to confirm or disprove. Reasons why such claimslack empirical evidence or testability according to most Multiverse theories is that other universes are in a differentspacetime framework, so in principle they cannot be observed.

Indirect Evidence

The logical foundation of modern science is hypothetico-deductive logic which permits a theory to proposeunobservable entities if these help explain observable outcomes, either by theory based predictions (of futureobservations) or retroductionism (of already known observations).[17]

Occam's Razor

Critics argue that to postulate a practically infinite number of unobservable universes just to explain our own seemscontrary to Occam's razor.[18] [19]

Tegmark answers:"A skeptic worries about all the information necessary to specify all those unseen worlds. But an entireensemble is often much simpler than one of its members. This principle can be stated more formallyusing the notion of algorithmic information content. The algorithmic information content in a number is,roughly speaking, the length of the shortest computer program that will produce that number as output.For example, consider the set of all integers. Which is simpler, the whole set or just one number?Naively, you might think that a single number is simpler, but the entire set can be generated by quite atrivial computer program, whereas a single number can be hugely long. Therefore, the whole set isactually simpler. Similarly, the set of all solutions to Einstein's field equations is simpler than a specificsolution. The former is described by a few equations, whereas the latter requires the specification of vastamounts of initial data on some hypersurface. The lesson is that complexity increases when we restrictour attention to one particular element in an ensemble, thereby losing the symmetry and simplicity thatwere inherent in the totality of all the elements taken together. In this sense, the higher-level multiversesare simpler. Going from our universe to the Level I multiverse eliminates the need to specify initialconditions, upgrading to Level II eliminates the need to specify physical constants, and the Level IVmultiverse eliminates the need to specify anything at all."

He continues:"A common feature of all four multiverse levels is that the simplest and arguably most elegant theory involves parallel universes by default. To deny the existence of those universes, 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

Multiverse 25

more wasteful and inelegant: many worlds or many words. Perhaps we will gradually get used to theweird ways of our cosmos and find its strangeness to be part of its charm."[4]

Multiverse hypotheses in philosophy and logic

Modal realismPossible worlds are a way of explaining probability, hypothetical statements and the like, and some philosopherssuch as David Lewis believe that all possible worlds exist, and are just as real as the actual world (a position knownas modal realism).[20]

Trans-world identityA metaphysical issue that crops up in multiverse schema that posit infinite identical copies of any given universe isthat of the notion that there can be identical objects in different possible worlds. According to the counterpart theoryof David Lewis, the objects should be regarded as similar rather than identical.[21] [22]

Fictional realismThe view that because fictions exist, fictional characters exist as well. There are fictional entities, in the same sensein which, setting aside philosophical disputes, there are people, Mondays, numbers and planets.[23] [24]

Multiverse hypotheses in religion and spirituality

HinduismThe concept of multiple universes is mentioned many times in Hindu Puranic literature, such as in the BhagavataPurana:

Because You are unlimited, neither the lords of heaven nor even You Yourself can ever reach the end ofYour glories. The countless universes, each enveloped in its shell, are compelled by the wheel of time towander within You, like particles of dust blowing about in the sky. The śrutis, following their method ofeliminating everything separate from the Supreme, become successful by revealing You as their finalconclusion (Bhagavata Purana 10.87.41)

IslamThere are seven verses in the Quran that specify that there are seven heavens. One verse says that each heaven or skyhas its own order, possibly meaning laws of nature. Another verse says after mentioning the seven heavens "andsimilar earths".

So [Allah] decreed them as seven heavens (one above the other) in two periods and revealed to eachheaven its orders. And We [Allah] adorned the lowest heaven with lights, and protection. Such is thedecree of the Exalted; the Knowledgeable. [Quran 41.12]

Fakhr al-Din al-Razi (1149–1209), in dealing with his conception of physics and the physical world in his Matalib,"explores the notion of the existence of a multiverse in the context of his commentary" on the Qur'anic verse, "Allpraise belongs to God, Lord of the Worlds." He raises the question of whether the term "worlds" in this verse refersto "multiple worlds within this single universe or cosmos, or to many other universes or a multiverse beyond thisknown universe." Al-Razi disagreed with the Aristotelian and Avicennian view of the impossibility of multipleuniverses. This disagreement arose from his affirmation of atomism, as advocated by the Ash'ari school of Islamictheology, which entails the existence of vacant space in which the atoms move, combine and separate.[25] He arguedthat God has the power to fill the vacuum with an infinite number of universes.[26]

Multiverse 26

Planes of existenceCertain religions and esoteric cosmologies propound the idea of a whole series of subtle emanated planes or worlds.

AfterlifeMany religions include an afterlife existence in realms, such as heavens and hells, which may be very different fromthe observable universe.

EschatologyEschatological scenarios may include a new different world after the end time of the current one. For example,Hindu cosmology includes the idea of an infinite cycle of births and deaths and an infinite number of universes witheach cycle lasting 8.4 billion years.[27]

Similar eschatological scenarios appear in other religions, in the form of belief in there being a new and differentworld after the end time of the current one.

References

Notes[1] James, William, The Will to Believe, 1895; and earlier in 1895, as cited in OED's new 2003 entry for "multiverse": "1895 W. JAMES in

Internat. Jrnl. Ethics 6 10 Visible nature is all plasticity and indifference, a multiverse, as one might call it, and not a universe."[2] Tegmark, Max (May 2003). "Parallel Universes". Scientific American.[3] Tegmark, Max (January 23 2003) (PDF). Parallel Universes (http:/ / space. mit. edu/ home/ tegmark/ multiverse. pdf). . Retrieved

2006-02-07. (PDF)[4] "Parallel universes. Not just a staple of science fiction, other universes are a direct implication of cosmological observations.", Tegmark M.,

Sci Am. 2003 May;288(5):40-51.[5] Max Tegmark (2003). "Parallel Universes". In "Science and Ultimate Reality: from Quantum to Cosmos", honoring John Wheeler's 90th

birthday. J. D. Barrow, P.C.W. Davies, & C.L. Harper eds. Cambridge University Press (2003). arXiv:astro-ph/0302131.Bibcode 2003astro.ph..2131T.

[6] Zyga, Lisa "Physicists Calculate Number of Parallel Universes" (http:/ / www. physorg. com/ news174921612. html), PhysOrg, 16 October2009.

[7] Tegmark, Max, The Interpretation of Quantum Mechanics: Many Worlds or Many Words? (http:/ / www. arxiv. org/ abs/ quant-ph/ 9709032/), 1998. Deutsch, David, David Deutsch's Many Worlds (http:/ / www. qubit. org/ people/ david/ Articles/ Frontiers. html), Frontiers, 1998.

[8] Tegmark, Max (January 23 2003) (PDF). Parallel Universes (http:/ / www. wintersteel. com/ files/ ShanaArticles/ multiverse. pdf). .Retrieved 2006-02-07. (PDF).

[9] J. Schmidhuber (1997): A Computer Scientist's View of Life, the Universe, and Everything. Lecture Notes in Computer Science, pp. 201-208,Springer: IDSIA - Dalle Molle Institute for Artificial Intelligence (http:/ / www. idsia. ch/ ~juergen/ everything/ )

[10] J. Schmidhuber (2000): Algorithmic Theories of Everything arXiv.org e-Print archive (http:/ / arxiv. org/ abs/ quant-ph/ 0011122)[11] J. Schmidhuber (2002): Hierarchies of generalized Kolmogorov complexities and nonenumerable universal measures computable in the

limit. International Journal of Foundations of Computer Science 13(4):587-612 IDSIA - Dalle Molle Institute for Artificial Intelligence (http:// www. idsia. ch/ ~juergen/ kolmogorov. html)

[12] J. Schmidhuber (2002): The Speed Prior: A New Simplicity Measure Yielding Near-Optimal Computable Predictions. Proc. 15th AnnualConference on Computational Learning Theory (COLT 2002), Sydney, Australia, Lecture Notes in Artificial Intelligence, pp. 216-228.Springer: IDSIA - Dalle Molle Institute for Artificial Intelligence (http:/ / www. idsia. ch/ ~juergen/ speedprior. html)

[13] Steven Weinberg(2005)" Living in the Multiverse (http:/ / arxiv. org/ abs/ hep-th/ 0511037v1)"[14] Richard J Szabo, An introduction to string theory and D-brane dynamics (2004)[15] Maurizio Gasperini, Elements of String Cosmology (2007)[16] Paul Halpern, The Great Beyond, 2005[17] Craig Rusbult, Ph.D[18] Trinh, Xuan Thuan (2006). Staune, Jean. ed. Science & the Search for Meaning: Perspectives from International Scientists. West

Conshohocken, PA: Templeton Foundation. p. 186. ISBN 1599471027.[19] Baird, Eric (2007). Relativity in Curved Spacetime. Chocolate Tree. p. 241. ISBN 0955706807.[20] Lewis, David (1986). On the Plurality of Worlds. Basil Blackwell. ISBN 0631224262.[21] Deutsch, Harry, "Relative Identity", The Stanford Encyclopedia of Philosophy (Summer '02), Edward N. Zalta (ed.) (http:/ / plato. stanford.

edu/ archives/ sum2002/ entries/ identity-relative/ )

Multiverse 27

[22] Paul B. Kantor "The Interpretation of Cultures and Possible Worlds", 1 October 2002 (http:/ / www. scils. rutgers. edu/ ~kantor/ 601/Ex_1Overview. html)

[23] IngentaConnect Home (http:/ / www. ingentaconnect. com/ content/ bpl/ phiq/ 2009/ 00000059/ 00000234/ art00009)[24] The Australian National University (http:/ / consciousness. anu. edu. au/ thomasson/ Fictional Entities. doc)[25] Adi Setia (2004). "Fakhr Al-Din Al-Razi on Physics and the Nature of the Physical World: A Preliminary Survey" (http:/ / findarticles. com/

p/ articles/ mi_m0QYQ/ is_2_2/ ai_n9532826/ ). Islam & Science 2. . Retrieved 2010-03-02[26] John Cooper (1998). "al-Razi, Fakhr al-Din (1149-1209)" (http:/ / www. muslimphilosophy. com/ ip/ rep/ H044. htm). Routledge

Encyclopedia of Philosophy (Routledge). . Retrieved 2010-03-07[27] Carl Sagan, Placido P D'Souza (1980s). Hindu cosmology's time-scale for the universe is in consonance with modern science. (http:/ / www.

rediff. com/ news/ jan/ 29sagan. htm); Dick Teresi (2002). Lost Discoveries: The Ancient Roots of Modern Science – from the Babylonians tothe Maya.

Bibliography• Bernard Carr, ed. (2007) Universe or Multiverse? Cambridge Univ. Press.• Deutsch, David (45841 1985). Splash. ed. Quantum theory, the Church-Turing principle and the universal

quantum computer (Proceedings of the Royal Society of London A 400 ed.). pp. 97–117.• Ellis, George F.R.; U. Kirchner, William R. Stoeger (2004). "Multiverses and physical cosmology". Monthly

Notices of the Royal Astronomical Society 347 (3): 921–936. arXiv:astro-ph/0305292.Bibcode 2004MNRAS.347..921E. doi:10.1111/j.1365-2966.2004.07261.x.

External links• Aurélien Barrau, " Physics in the Multiverse. (http:/ / lpsc. in2p3. fr/ ams/ aurelien/ aurelien/ CCDecMULTIV.

pdf)"• --------, " Multiple Universes? (http:/ / www. laviedesidees. fr/ Des-univers-multiples. html)" (in French). Review

of Carr (2007).• Davies, Paul (2004). "Multiverse Cosmological Models". Mod.Phys.Lett. A 19: 727–744.

arXiv:astro-ph/0403047. Bibcode 2003MPLA...18.2895M. doi:10.1142/S0217732303012325.• Max Tegmark (2003) " Parallel Universes. Not just a staple of science fiction, other universes are a direct

implication of cosmological observations. (http:/ / space. mit. edu/ home/ tegmark/ PDF/ multiverse_sciam. pdf)"• David Deutsch (2001) " The Structure of the Multiverse. (http:/ / xxx. lanl. gov/ abs/ quant-ph/ 0104033)"• BBC Horizon -Parallel Universes. (http:/ / www. bbc. co. uk/ science/ horizon/ 2001/ parallelunitrans. shtml)• Michael Price's Everett FAQ. (http:/ / www. hedweb. com/ manworld. htm)• Jürgen Schmidhuber, " The ensemble of universes describable by constructive mathematics. (http:/ / www. idsia.

ch/ ~juergen/ computeruniverse. html)"• Interview with Tufts cosmologist Alex Vilenkin (http:/ / thoughtcast. org/ casts/

the-end-of-our-universe-among-other-timely-topics) on his new book, "Many Worlds in One: The Search forOther Universes" on the podcast and public radio interview program ThoughtCast. (http:/ / www. thoughtcast.org)

• Joseph Pine II about Multiverse (http:/ / www. upstream. nl/ comments. php?id=751_0_1_0_C), Presentation atMobile Monday Amsterdam, 2008

• Multiverse - Radio-discussion on [[BBC Four (http:/ / www. bbc. co. uk/ programmes/ b008z744)] with MelvynBragg]

Chaotic Inflation theory 28

Chaotic Inflation theoryThe Chaotic Inflation theory is a variety of the inflationary universe model, which is itself an outgrowth (orextension) of the Big Bang theory. Chaotic Inflation, proposed by physicist Andrei Linde, models our universe asone of many that grew as part of a multiverse owing to a vacuum that had not decayed to its ground state. In thistheory, the peaks in the evolution of a scalar field (determining the energy of the vacuum) correspond to regions ofrapid inflation which dominate, creating "bubble universes," making the structure of space fractal on the very largestscales, likely at scales larger than the observable universe. Chaotic Inflation (along with some other types ofinflation) is usually a sub-class of eternal inflation,[1] since the expansion of the inflationary peaks exhibit positivefeedback and come to dominate the large scale dynamics of the universe. Alan Guth's 2007 paper, Eternal inflationand its implications [2][1] details what is now known on the subject, and demonstrates that this particular flavor ofInflationary universe theory is relatively current, or is still considered viable, more than 20 years after its inception.[3]

[4] [5]

HistoryInflation, or the inflationary universe theory, was developed as a way to overcome the few remaining problems withwhat was otherwise considered a successful theory of cosmology, the Big Bang model. It is now known that AlexeiStarobinsky, at the L.D. Landau Institute of Theoretical Physics in Moscow developed the first realistic Inflationtheory in 1979[6] [7] but failed to articulate its relevance to modern cosmological problems. Due to politicaldifficulties in the former Soviet Union, regarding the free exchange of scientific knowledge, most scientists outsidethe USSR remained ignorant about Starobinsky’s work until years later. Starobinsky's model was relativelycomplicated, however, and said little about how the inflation process could start.In 1979 Alan Guth of the United States developed an inflationary model independently, which did offer amechanism for inflation to begin, the decay of a so-called false vacuum into 'bubbles' of 'true vacuum' that expandedat the speed of light. Guth coined the term, “inflation,” and he was the first to discuss the theory with other scientistsworldwide. But this formulation was problematic, as there was no consistent way to bring an end to the inflationaryepoch and end up with the isotropic, homogeneous Universe observed today. (See False vacuum#Developments oftheory). In 1982, this "graceful exit problem" was solved by Andreas Albrecht and Paul J. Steinhardt and alsoindependently by Andrei Linde.In 1986, Linde published an alternative model of inflation that also reproduced the same successes of new inflationentitled "Eternally Existing Self-Reproducing Chaotic Inflationary Universe,"[8] which provides a detaileddescription of what has become known as the Chaotic Inflation theory or eternal inflation. The Chaotic Inflationtheory is in some ways similar to Fred Hoyle’s Steady state theory, as it employs the metaphor of a universe that iseternally existing, and thus does not require a unique beginning or an ultimate end of the cosmos.

Quantum fluctuations of the inflation fieldChaotic Inflation theory models quantum fluctuations in the rate of inflation.[9] Those regions with a higher rate ofinflation expand faster and dominate the universe, despite the natural tendency of inflation to end in other regions.This allows inflation to continue forever, to produce future-eternal inflation.

Within the framework of established knowledge of physics and cosmology, our universe could be one of many in a super-universe or multiverse. Linde (1990, 1994) has proposed that a background space-time "foam" empty of matter and radiation will experience local quantum fluctuations in curvature, forming many bubbles of false vacuum that individually inflate into mini-universes with random characteristics. Each universe within the multiverse can have a different set of constants and physical laws. Some might have life of a form different from ours; others might have no life at all or something even more complex or so different that we cannot even

Chaotic Inflation theory 29

imagine it. Obviously we are in one of those universes with life.[10]

—Victor J. StengerPast-eternal models have been proposed which adhere to the perfect cosmological principle and have features of thesteady state cosmos.[11] [12] [13]

Differential decayIn standard inflation, inflationary expansion occurred while the universe was in a false vacuum state, halting whenthe universe decayed to a true vacuum state becoming a general and inclusive phenomenon with homogeneitythroughout, yielding a single expanding universe which is “our general reality” wherein the laws of physics areconsistent throughout. In this case, the physical laws "just happen" to be compatible with the evolution of life.The bubble universe model proposes that different regions of this inflationary universe (termed a multiverse)decayed to a true vacuum state at different times, with decaying regions corresponding to “sub”- universes not incausal contact with each other and resulting in different physical laws in different regions which are then subject to“selection” which determine each region’s components based upon (dependent on) the survivability of the quantumcomponents within that region. The end result will be a finite number of universes with physical laws consistentwithin each region of spacetime.

False vacuum and true vacuumVariants of the bubble universe model postulate multiple false vacuum states, which result in lower-energyfalse-vacuum “progeny” universes spawned, which in turn produce true vacuum state progeny universes withinthemselves.

Evidence from the Fluctuation Level in our UniverseIt has shown that new inflation does not produce a perfectly symmetric universe, but that tiny quantum fluctuationsin the inflaton are created. These tiny fluctuations form the primordial seeds for all structure created in the lateruniverse. These fluctuations were first calculated by Viatcheslav Mukhanov and G. V. Chibisov in the Soviet Unionin analyzing Starobinsky's similar model.[14] [15] [16] In the context of inflation, they were worked out independentlyof the work of Mukhanov and Chibisov at the three-week 1982 Nuffield Workshop on the Very Early Universe atCambridge University.[17] The fluctuations were calculated by four groups working separately over the course of theworkshop: Stephen Hawking;[18] Starobinsky;[19] Guth and So-Young Pi;[20] and James M. Bardeen, Paul Steinhardtand Michael Turner.[21]

The agreement of these models with the predictions of WMAP data adds weight to the idea that the universe is selfcaused by such a method. Although promising, many physicist take such evidence with a cautious optimism.[22]

References

Calculating God 30

Calculating GodCalculating God is a 2000 science fiction novel by Robert J. Sawyer. It takes place in the present day and describesthe arrival on Earth of sentient aliens. The bulk of the novel covers the many discussions and arguments on thistopic, as well as about the nature of belief, religion, and science. Calculating God received nominations for both theHugo and John W. Campbell Memorial Awards in 2001.[1]

Plot summaryThomas Jericho, a paleontologist working at the Royal Ontario Museum in Toronto, makes the first human-to-aliencontact when a spider-like alien arrives on Earth to investigate Earth's evolutionary history. The alien, Hollus, andher crewmembers have come to Earth to gain access to the museum's large collection of fossils, and to studyaccumulated human knowledge in order to gather evidence of the existence of God. It seems that Earth and Hollus'home planet, and the home planet of another alien species traveling with Hollus, all experienced the same fivecataclysmic events at roughly the same time. Hollus believes that the universe was created by a god, to provide aplace where life could develop and evolve. Thomas Jericho is an atheist who provides a balance to the philosophicaldiscussion regarding the existence of gods.At the end the star Betelgeuse becomes a supernova, threatening all life within hundreds of light-years withirradiation. One of several dead civilizations discovered by the alien explorers deliberately induced the supernova inorder to sterilize the stellar neighborhood. This was done in order to protect the virtual reality machinery which nowhoused all of their personalities. According to the alien visitors, several such worlds exist where the inhabitantsuploaded themselves into machines instead of exploring the nature of the Universe and gods.Although the supernova happened over 400 years before the events of the novel, the radiation is just reaching Earth.However, the alien ship's advanced telescope in orbit then sees a large black entity emerge from space itself andcover the exploding star. This is final proof that a controlling intelligence is guiding and preserving some life-forms.In the final chapter, the scientist, who is dying of cancer, travels to the entity on the alien ship, where a fusion ofgenetic materials from human and alien sources produces a new intelligence able to live in space and possibly createits own Universe.

Notes[1] "2001 Award Winners & Nominees" (http:/ / www. worldswithoutend. com/ books_year_index. asp?year=2001). Worlds Without End. .

Retrieved 2009-09-19.

References• Cassada, Jackie. "Calculating God (Book review)." Library Journal 125.7 (15 Apr. 2000): 126.• Flynn, Tom. "SCIENCE FICTION GOES ANTHROPIC." Free Inquiry 22.1 (Winter2001/2002 2001): 62.• "forecasts: Fiction." Publishers Weekly 247.12 (20 Mar. 2000): 75.• Johnson, Roberta. "Adult Books: FICTION." Booklist 96.16 (15 Apr. 2000): 1534.• Seidman, Barry F. "Using Science Fiction to Promote Creationism." Skeptical Inquirer 26.2 (Mar. 2002): 53-54.

Calculating God 31

External links• Calculating God (http:/ / www. isfdb. org/ cgi-bin/ title. cgi?21443) publication history at the Internet Speculative

Fiction Database• Calculating God on sfwriter.com (http:/ / www. sfwriter. com/ excg. htm)• Calculating God (http:/ / www. worldswithoutend. com/ novel. asp?ID=67) at Worlds Without End• Audio review and discussion of Calculating God (http:/ / www. sfbrp. com/ archives/ 164) at The Science Fiction

Book Review Podcast (http:/ / www. sfbrp. com/ )

Article Sources and Contributors 32

Article Sources and ContributorsFine-tuned Universe  Source: http://en.wikipedia.org/w/index.php?oldid=428569652  Contributors: A ghost, AaronM, Alec.brady, Alexis Brooke M, Altenmann, Andycjp, Annoynmous,Anupam, Armchair info guy, Army1987, Ashmoo, Aunt Entropy, B4hand, B9 hummingbird hovering, Baegis, Bagginator, Barbara Shack, Barticus88, BaxterG4, Bdesham, Ben Standeven,Benna, Bertsche, Big iron, Billjefferys, Bkell, Bobrayner, Brandmeister, BrettAllen, Bryan Derksen, CDN99, CSvBibra, Certh, Chanakal, Charles Matthews, Charlesdrakew, Coffee2theorems,CommonsDelinker, Cpuz, Cyde, D'uberville, DGG, DOSGuy, DannyMuse, Dave souza, Dawn Bard, Decumanus, Desoto10, Dicklyon, Diza, Dojarca, Donarreiskoffer, Duncharris, Ec5618, El C,Endomion, Excirial, Eyu100, Fama Clamosa, Feeeshboy, FeloniousMonk, Florin zeitblom, FrozenUmbrella, GDallimore, Gabbe, Gareth McCaughan, Gkc, Goethean, Gregbard, Gråbergs GråaSång, Guettarda, Gwguffey, Halcatalyst, Headbomb, Highlander, Hirak 99, Histrion, Hrafn, Hyperdeath, IgorSF, Inswoon, Ivan Godard, Jaganjac, JamesBWatson, Jason One, Jefffire, Jheald,Jim62sch, JimR, Johnuniq, Jok2000, Jordgette, K, Kappa, Karada, Kerowyn, KillerChihuahua, Kizor, Kznf, Laur, Lexor, Liberatus, Linas, Lumenos, Maedin, Manning Bartlett, MarcelB612,Mbell, Mboverload, Michael Hardy, Momergil, MrBell, MuZemike, N4nojohn, NBeale, Northfox, Nurban, Nyenyec, Olin, Orangemarlin, PaddyLeahy, Paradoctor, Pcarbonn, Peak, Phildogg82,Plumbago, Protostan, Proxima Centauri, RK, RainbowCrane, Random account 47, Rbj, Renamed user 4, Rholton, Richard001, Rjwilmsi, Roadrunner, Robhu, Romanpoet, Scott3, Selket,SheffieldSteel, Shika234, Sir Paul, Soulkeeper, Spark, SunCreator, Supermagle, Sverdrup, TableManners, Tdoune, Thiseye, Threedots dead, Timurghlu, Timwi, Tktktk, Tlogmer, Torchwoodwho,Ttiotsw, Twelvethirteen, Tznkai, UFu, UberScienceNerd, Ungvichian, Vanished User 0001, VanishedUser314159, Vsmith, WAS 4.250, Wavelength, Wdanwatts, WpZurp, Xyzzyplugh, Yath,Zerokitsune, ZorkFox, Zundark, Ü, 326 anonymous edits

Anthropic principle  Source: http://en.wikipedia.org/w/index.php?oldid=428944215  Contributors: 1dragon, 200.191.188.xxx, 213.253.39.xxx, A ghost, A3 nm, Aarghdvaark, AaronSw,Academic Challenger, Acalamari, Albertod4, Alfio, Alibaba, Ammodramus, Andonic, Andrewthomas10, Andycjp, Angela, Anthony on Stilts, Arioch7, Ask123, Asterion, Aunt Entropy, Az1568,B4hand, Banno, Barbara Shack, Bejnar, Bettymnz4, Billjefferys, BlaiseFEgan, Bludsucker, Bm gub, Boud, Brianroemen, Bryan Derksen, Btyner, Bubba73, CRGreathouse, CSvBibra, Carlon,Caroldermoid, Cassowary, Charlesdrakew, Claus L. Rasmussen, Closedmouth, Concerned cynic, Crumley, Cybercobra, Cyde, D6, DV8 2XL, Danburke, Dandv, DaveApter, Deathphoenix,DedalusJMMR, Derek Ross, Desmay, Discrepancy, Diza, Dmyersturnbull, DopefishJustin, Dr. Submillimeter, DrRetard, Edgar181, EdgarCarpenter, Edgarde, Epistemion, Epstewart,Euphrosyne, FForeclosers, FT2, Fairandbalanced, Fcn, Fences and windows, Firefly322, Fragglet, Fredrik, Friendly Neighbour, Gaius Cornelius, Gandalf61, Gene Ward Smith,Georgewilliamherbert, GirasoleDE, GlacierSupremacy, Glen, Goethean, Golbez, Goldfinger820, Gracefool, Graham87, Gregbard, Guoguo12, Gwern, Hans Adler, Headbomb, Highlander,Horn.imh, Ht686rg90, Huhnra, IRP, IRWolfie-, Iknowyourider, Info D, Infovoria, InverseHypercube, Island1, J8079s, Jaganath, Japanese Searobin, Jarry1250, Jjalexand, Jlrobertson, Joehubris,Joeseither, John, JohnCD, Johnstone, Joke137, Joncolvin, Jordgette, Joso98, JulesH, JureLc, Justin W Smith, Jwjdiamond, KarlHallowell, Karol Langner, Kenneth M Burke, Kosmocentric,Lightmouse, LittleHow, Localzuk, Loodog, Looxix, Lpgeffen, Lukebarnesy, Lulu of the Lotus-Eaters, Lumidek, Luís Felipe Braga, Lycanthrope, MER-C, Malcolm Farmer, MarcelB612,Marsiancba, Marudubshinki, Mattbrundage, Mattgrommes, Mav, Mbell, Mc6809e, Menchi, Mentifisto, Miguel.mateo, Mirv, Mitteldorf, Monoape, Monty845, Mr Owl1234, Mrbrownn, Nekura,Nickkid5, Nurban, Ocatecir, Olaf Davis, Orangemarlin, OriEri, Pablo Mayrgundter, PaddyLeahy, Paradoctor, Paul Richter, Pcarbonn, Peak, Phil Boswell, Plumbago, Plusorminuszero, Portillo,Possum, Pseudovector, Ptcamn, Qrsdogg, QuantumEleven, RK, Rbj, Reddi, Reinis, Res2216firestar, Rfl, Rhobite, Rich Farmbrough, Richard D. LeCour, Richard Tierney, Richard001, Ringbang,Rjwilmsi, Rmrfstar, Roadrunner, Robertd, Robinh, Ronald King, Ryulong, Samsara, Schnufflus, Sderose, Shadowjams, Sm8900, Snowdog, Snoyes, Soler97, SpigotMap, Staecker, Stormwriter,Sverdrup, Swift, Swpb, TakuyaMurata, TeleComNasSprVen, Telecineguy, Tesseract2, The Anome, The Epopt, TheMile, Thiseye, Thumperward, Ti-30X, Tim Ivorson, Timc, Timl2k4, Timwi,Tirral, Tnxman307, Toby Woodwark, Tom harrison, Tomato, Tritium6, Tualha, TutterMouse, VanishedUser314159, Variable, WLU, Wesley, Wexcan, Whiner01, Wickethewok, WikHead,WikiSlasher, Wikianiki, WilliamKF, XJamRastafire, 452 anonymous edits

Multiverse  Source: http://en.wikipedia.org/w/index.php?oldid=427588780  Contributors: 09dhummel, 213.253.39.xxx, Aaron Bowen, AbstractClass, Addihockey10, Admiral Roo, Adrigon,Aitias, Ajcheema, Alansohn, Albertmin, Alex earlier account, Allen234, Alxeedo, Amnuel, Anarchia, Androo, Angela, Annaalexandrae, Anonymous Dissident, Another disinterested reader, Ant,Anthony on Stilts, Anville, Apeloverage, Apostrophe, Arion 3x3, Armeria, AstroWiki, Athanatsius, Athenean, AxG, B4hand, Bacabed, Barbara Shack, Bartledan, Beardo, BenBaker, BenRG,BenRayfield, Bernard Marx, Beyond My Ken, Bfinn, BigBang616, Blehfu, BlueNight, BobKawanaka, Bobo192, Boing! said Zebedee, Boud, BrianY, Brighterorange, Bryan Derksen,CHBMch05, CRGreathouse, CSTAR, Casimir9999, Cassowary, Cfortunato, CharlesC, Chasrob, Chimesmonster, Chris the speller, Chrisdann, Christinedoby, Chunminghan, Ciphergoth,Cloudblazer, Clq, Conversion script, Crobichaud, Css, Curst Saden, Cyberdiablo, DCNanney, DV8 2XL, Daniel Newman, Danogo, Darklilac, DarthSidious, Dazedbythebell, Dbachmann,Dcoetzee, Delirium, Derek Ross, Deville, Dianelos, Dillee1, Discrepancy, Djf2564, Dlarmore, Dmitrybrant, Doczilla, Dominik92, Dorftrottel, Drbogdan, Dream of Nyx, EdBever,EdgarCarpenter, Editorius, Eequor, Ehheh, Emperorbma, Eridani, Escape Orbit, ExternalGazer, Fabartus, Fairandbalanced, Falcorian, FeanorStar7, Fermion, Firsfron, Fishal, Foosher,Freakofnurture, GateKeeper, Gco, Gdm, GentlemanGhost, Geoffr, GeorgiaSLee, Geshel, Giftlite, Gil987, Gioto, Glastohead, Gracefool, Graeme Bartlett, Greenguy1090, Grunt, Gtrmp, Hac13,Hadal, Handsaw, Hanjunjade, Hannes Karnoefel, Hans Adler, Hathaldir, Hawkaris, Haxwell, Headbomb, Hemlock Martinis, Hephaestos, HieronymousCrowley, Hiplibrarianship, Hrafn,Ht686rg90, Hu, Ictlogist, Ilmari Karonen, Imad marie, IomPsinso, Iridescent, Ito123456789, J04n, JHunterJ, Jagged 85, Jamelan, JamesAM, Jeff3000, JeffStickney, JeffreyN, Jenattiyeh, JeromeCharles Potts, JoanneB, Joecab, Johnbmckenna, Johnpseudo, Johnstone, Joke137, Joncolvin, Joseph Solis in Australia, JoshuaZ, Joshuajohnlee, K a r n a, K00bine, K0hlrabi, K1234567890y,KGasso, Keeganp, KelleyCook, Khaosworks, Kilo39, Kingpin13, Kintetsubuffalo, Kitch, Kmarinas86, Knowledge Seeker, Kookyunii, Kozuch, Krawi, Kriak, Kriss12, KronicTOOL, Kurrupt3d,Kurtilein, Lambiam, Latka, Lefty, LinkinPark, Livajo, Longhandle1137, Lotje, MJMyers2, Machine Elf 1735, MadIce, Magioladitis, MakeRocketGoNow, Makyen, Malcolmxl5, Martarius,Martg76, Masqline, Masterpiece2000, MattB2, Mbroderick271, McSly, Mchmike, Mel Etitis, Meneth, Metamagician3000, Miami33139, Michael C Price, Michael Hardy, Mike Peel, MikeRosoft, Mike18xx, Mirage GSM, Mjkrol, Modemac, Modster, Moogsi, Moosester, Morwen, Mpfrank, Mporter, MrH3MinuteMile, Mshonle, MuZemike, Nakon, Naroood, Neparis, Netdragon,Netkinetic, NewEnglandYankee, Newone, Nfenn, Noah Salzman, Noetica, Obey, Ohnoitsjamie, Old Moonraker, Olivier, Ollj, Osprey9713, Ott, Parsifal, Parsiferon, Pascal666, Patrick, Pcarbonn,Peter.thelander, Peterdjones, Petersam, Pfahlstrom, Philip Stevens, Phoenix2, Pitamakan, Pne, PointedEars, PoisonGM, Police officer, Poor Yorick, Projectyugo, Pwqn, RA0808, Radon210,Ran4, Rbj, Rchamberlain, Reedy, Renamed user 4, Reuben, Richard D. LeCour, Richard-r-v, Richardvanas1, Rickard Vogelberg, RickardV, Riction, Riemann Zeta, Riraito, Rjwilmsi, Rory096,Roy7, RoyBoy, Rrburke, Rursus, Salix alba, Sam, Sam Hocevar, Sapphic, Saswann, Scarian, Sedecrem, SeniorInt, Shadowblade, ShakingSpirit, ShaunMacPherson, Shiritai, Silicianer, Siroxo,Sjorford, Skakkle, Slightsmile, Slivester, Smurfsider, SnowFire, Soilguy5, Sophus Bie, Spartan, Spikehay, Spydra, Stemonitis, Steve Quinn, Steven Avraham Rosten, Stoned philosophaster,Stupidjassi, Sunwukongmonkeygod, Taigei, Tarotcards, Teflon Don, Thanos6, Thanose, Thatguyflint, The Anome, The Anonymous One, TheGrimReaper NS, ThisIsRealPuma, Three887, Tiderolls, Tim Starling, Titanium Dragon, Tlogmer, Tomisti, Troublemane, Trusilver, Tverbeek, Twoshotted, UBeR, UberScienceNerd, Uruk2008, Vald, Valoem, Vampus, Vanished User 0001,VanishedUser314159, Vyznev Xnebara, WAS 4.250, Waza, Wednesday Next, Wereon, Wesley J M, Whosasking, Wikianon, WikipedianMarlith, Wikipelli, Winterus, Wylfing, XDanielx,Xammer, Xiner, Yboc2000, Z E U S, Zaian, Zetawoof, Zhonghuo, Zippedmartin, Zx-man, ²¹², 695 anonymous edits

Chaotic Inflation theory  Source: http://en.wikipedia.org/w/index.php?oldid=428203732  Contributors: Art Carlson, Barbara Shack, CanadianLinuxUser, Chasrob, Epbr123, Escape Orbit,Ethansiegel, George Church, GregorB, Headbomb, Ideogram, JonathanD, Kostisl, Kurtan, Lambiam, Magog the Ogre, Marcus MacGregor, Michael C Price, Michael Hardy, Mr0t1633,Northumbrian, Pearle, Ravindranno2, Red1pa, Rjwilmsi, RogueNinja, Shadypalm88, SwordSmurf, Templatehater, Ter890, Thunderhippo, Tim Shuba, Tomyg90, VanishedUser314159,Whitepaw, Zachareth, Zharradan.angelfire, Zoz, 26 anonymous edits

Calculating God  Source: http://en.wikipedia.org/w/index.php?oldid=421082620  Contributors: Bearcat, Captain-tucker, DivaNtrainin, Djdaedalus, EnBob08, Henry Merrivale, Icowrich, Jerzy,John, Niels E, Rich Farmbrough, Shogun, Tony Sidaway, 13 anonymous edits

Image Sources, Licenses and Contributors 33

Image Sources, Licenses and ContributorsImage:Eta Carinae Nebula 1.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Eta_Carinae_Nebula_1.jpg  License: unknown  Contributors: Hubble image: NASA, ESA, N. Smith(University of California, Berkeley), and The Hubble Heritage Team (STScI/AURA) CTIO data: N. Smith (University of California, Berkeley) and NOAO/AURA/NSFFile:Multiverse - level II.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Multiverse_-_level_II.svg  License: Public Domain  Contributors: User:K1234567890y, User:Lokal_Profil

License 34

LicenseCreative Commons Attribution-Share Alike 3.0 Unportedhttp:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/