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Fine-tuned universe

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The fine-tuned Universe is the idea that conditions that allow life in the Universe can only occur with the tightly restricted values of the universal physical constants, and that if any of several fundamental constants were only slightly different the universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is presently understood. [1]

The arguments relating to the fine-tuned universe concept are related to the anthropic principle, which states that any valid theory of the universe must be consistent with our existence as human beings at this particular time and place in the universe. In other words, even if the actual probability of a universe that supports intelligent life is very low, the conditional probability of supporting intelligent life, given our existence in it, is 1. Even if there could be other universes, less "fine-tuned" and so devoid of life, there would be no one there to observe them.

Premise

Fine-tuned Universe proponents argue that deep-space structures such as the Eta Carinae Nebula would not form in a universe with significantly different physical constants. Photo: HST / NASA / ESA.

The premise of the fine-tuned universe assertion is that a small change in several of the approximately 26 dimensionless fundamental physical constants would make the universe radically different: if, for example, the strong nuclear force were 2% stronger than it is (i.e. if the coupling constant representing its strength were 2% larger), diprotons would be stable and hydrogen would fuse into them instead of deuterium and helium. This would drastically alter the physics of stars, and presumably prevent the universe from developing life as it is currently observed on the earth. However, many of the 26 constants describe the properties of the unstable strange, charmed, bottom and top quarks and mu and tau leptons which seem to play little part in the universe or the structure of matter. It seems unlikely that the precise values of these constants are important for life; at any rate they are not included in the usual discussion of fine-tuning.

Larry Abbott describes the issue thus: "the small value of the cosmological constant is telling us that a remarkably precise and totally unexpected relation exists among all the parameters of the Standard Model of particle physics, the bare cosmological constant and unknown physics."[2] Victor Stenger characterizes the fine-tuned universe concept as capable of being interpreted as a "claim of evidence for divine cosmic plan": "As the argument goes, the chance that any initially random set of constants would correspond to the set of values that we find in our universe is very small and the universe is exceedingly unlikely to be the result of mindless chance. Rather, an intelligent, purposeful Creator must have arranged the constants to support life". Stenger in that paper is critical of the claims of the fine-tuning advocates and provides his own explanations highlighting the flaws in those claims, concluding that "The universe is not fine-tuned for humanity. Humanity is fine-tuned to the universe".[3]

As modern cosmology developed, various hypotheses have been proposed (including an oscillatory universe or a multiverse) where physical constants are postulated to resolve themselves to random values in different iterations of reality, resulting in separate parts of reality with wildly different characteristics. In such scenarios the issue of fine-tuning does not arise at all, as only those "universes" with constants hospitable to life (such as what we observe) would develop life capable of pondering the question.

Though there are fine tuning arguments that are naturalistic,[4] the assertion that the universe was designed to be fine-tuned is largely promoted by advocates of intelligent design and other forms of creationism. This apparent fine-tuning of the universe is cited[5] as an evidence for the existence of God or some form of intelligence capable of manipulating (or designing) the basic physics that governs the universe.

Critics of both the fine-tuned universe assertion and the anthropic principle argue that they are essentially a tautology.[6] The claim of a fine-tuned universe has also been criticized as an argument by lack of imagination for assuming no other forms of life are possible (see also alternative biochemistry). In addition, critics see it as an example of backwards reasoning since it asserts that the universe is adapted to humans instead of that humans are adapted to the universe through the process of evolution. Critics also see it as an example of the logical flaw of hubris or anthropocentrism in its assertion that humans are the purpose of the universe.[7]

Nature of the constants

Modern science as practiced since René Descartes is reductionist, meaning that it attempts to discover the most fundamental objects and rules governing the observable behavior of the universe. In descriptions of the physical universe, fundamental rules take the form of laws (usually equations relating physical quantities and properties) involving physical constants, while the fundamental objects are elementary particles with constant mass, charge, and other physical properties. This reductionism is a pragmatic approach that obtains results and is not a philosophical position on ontology. The nature of these constants is a much debated topic in physics and metaphysics (see string theory).

Meaning of "universe"

Both popular and professional research articles in cosmology often use the term "universe" to refer to the observable universe. The reason for this usage is that only observable phenomena are scientifically relevant. Since unobservable phenomena have no perceptible effects, physicists argue that they "causally do not exist". Since unobservable parts of the universe cannot be measured, hypotheses about them are not testable, and thus inappropriate for a scientific theory.

In metaphysics, "universe" refers to everything that exists. This encompasses both observable and unobservable phenomena. Metaphysics seeks to describe everything that is knowable about existence.

All the arguments that refer to the observable universe would not necessarily apply to the unobservable parts of reality sometimes called "other universes", if such there be. Although our observable universe has the parameters necessary for carbon based life, other parts of a larger multiverse may be sterile, or may have physical parameters conducive to different types of life or other, possibly self-aware, systems.

Possible fine-tuning

There are many cases where the known physical constants suggest fine tuning. These and other examples are often given as evidence of the universe being fine-tuned. Whether they actually are proof of fine-tuning is a matter debated between proponents of the fine-tuning argument and critics who feel that such reasoning is a subjective anthropomorphism of natural physical constants or, in the words of Victor Stenger, that "...The fine-tuning argument and other recent intelligent design arguments are modern versions of God-of-the-gaps reasoning, where a God is deemed necessary whenever science has not fully explained some phenomenon.". Victor Stenger furthers his critical view that "...a wide variation of constants of physics leads to universes that are long-lived enough for life to evolve, although human life need not exist in such universes".[3]

Implications of fine tuning

Fine-Tuning comes with caveats. The fact that a universe with different physical constants might be inhospitable to life as we know it does not necessarily mean that it is inhospitable to any form of life. Currently, there is no way of determining if a universe allows for life or not. Further, most of this universe, especially the interstellar vacuum, appears to be devoid of life; other physical constants may exist that allow a much greater density of life than in this universe.

There could possibly be exotic life with “different configurations of laws and constants of physics” [3]. Life could perhaps have developed based on different chemicals. Life could be based on silicon or other carbon-like chemical elements, though carbon seems better suited.

First and foremost, and fatal to the design argument all by itself, we have the wholly unwarranted assumption that only one type of life is possible—the particular form of carbon-based life we have here on earth.

— Victor J. Stenger, [4]

Life might be possible based on atoms rather than molecules in a universe with different laws and parameters. If there are other sapient and sentient beings in a totally different universe living in totally different bodies, they may well ask the identical question as to why the constants of their universe fall within a narrow range that allows them to exist.

Naturalistic possibilities

If it is accepted that the universe is fine-tuned, there are a number of naturalistic explanations that attempt to account for it.

Multiverse

Main article: Multiverse

This assumes the existence of many universes with different physical constants, some of which are hospitable to intelligent life. See The multiverse and the anthropic principle. Because we are intelligent beings, we are by definition in a hospitable one. This approach has led to considerable research into the anthropic principle and has been of particular interest to particle physicists because theories of everything do apparently generate large numbers of universes in which the physical constants vary widely. As of yet, there is no evidence for the existence of a multiverse, but some versions of the theory do make predictions which some researchers studying M-theory and gravity leaks hope to see some evidence of soon.[8] The existence of universes in a multiverse other than the observable universe is not falsifiable, thus some are reluctant to call the multiverse idea a "scientific" idea. UNC-Chapel Hill professor Laura Mersini-Houghton claims that the WMAP cold spot may provide testable empirical evidence for a parallel universe.

Variants on this approach include:

Cosmological natural selection

Main article: Cosmological natural selection

Ekpyrotic universe

Main article: Ekpyrotic

Bubble universe theory

Main article: Chaotic inflation theory
See also: Multiverse § Bubble theory

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

According to this scenario, by means of a random quantum fluctuation the universe "tunneled" from pure vacuum ("nothing") to what is called a false vacuum, a region of space that contains no matter or radiation but is not quite "nothing." The space inside this bubble of false vacuum was curved, or warped. A small amount of energy was contained in that curvature, somewhat like the energy stored in a strung bow. This ostensible violation of energy conservation is allowed by the Heisenberg uncertainty principle for sufficiently small time intervals. The bubble then inflated exponentially and the universe grew by many orders of magnitude in a tiny fraction of a second. (For a not-too-technical discussion, see Stenger 1990). As the bubble expanded, its curvature energy was converted into matter and radiation, inflation stopped, and the more linear big bang expansion we now experience commenced. The universe cooled and its structure spontaneously froze out, as formless water vapor freezes into snowflakes whose unique patterns arise from a combination of symmetry and randomness.

— Victor J. Stenger, The Anthropic Coincidences[9]

Different bubble universes can have different laws of physics. We happen to be in a universe where our type of life is possible.

So how did our universe happen to be so "fine-tuned" as to produce these wonderful, self-important carbon structures? As I explained above, we have no reason to assume that ours is the only possible form of life and perhaps life of some sort would have happened whatever form the universe took—however the crystals on the arm of the snowflake happened to be arranged by chance.

— Victor J. Stenger, The Anthropic Coincidences[9]

In standard inflation, inflationary expansion occurred while the universe was in a false vacuum state, halting when the universe decayed to a true vacuum state. The bubble universe model proposes that different parts of this inflationary universe (termed a Multiverse) decayed at different times, with decaying regions corresponding to universes not in causal contact with each other.

Alien design

The Universe may have been designed by an alien or by aliens. This would solve the problem of how a designer or design team capable of fine-tuning the Universe could come to exist. Leading cosmologist, Alan Guth believes humans will in time be able to generate new universes. By implication previous intelligent entities may have generated our universe.

I in fact have worked with several other people for some period of time on the question of whether or not it's in principle possible to create a new universe in the laboratory. Whether or not it really works we don't know for sure. It looks like it probably would work. It's actually safe to create a universe in your basement. It would not displace the universe around it even though it would grow tremendously. It would actually create its own space as it grows and in fact in a very short fraction of a second it would splice itself off completely from our Universe and evolve as an isolated closed universe growing to cosmic proportions without displacing any of the territory that we currently lay claim to.

— Alan Guth[10]

Possibly the extraterrestrial designer/designers evolved in a universe, which can sustain life despite being less finely tuned than ours. If any designer or design team are members of a species which evolved then there is or was a breeding population of the designer species. A designer is not one single supreme being. Note, one single designer would need to be very much more capable than any individual member of a design team cooperating together. Therefore Occam's razor may favour a design team.

Or maybe the elusive “crane” that cosmologists seek will be a version of Darwin’s idea itself: either Smolin’s model or something similar. Or maybe it will be the Multiverse plus Anthropic principle espoused by Martin Rees and others. It may even be a Superhuman designer – but if so it will most certainly not be a designer who just popped into existence, or who always existed. If (which I don’t believe for a moment) our universe was designed, and a fortiori if the designer reads our thoughts and hands out omniscient advice, forgiveness and redemption, the designer himself must be the end product of some kind of cumulative escalator or crane, perhaps a version of Darwinism in another universe.

— Richard Dawkins, The God Delusion

Dawkins maintains that an alien designer or designers are more plausible than a supernatural designer or designers because there is a known mechanism to produce them. He calls it the “crane” of Natural selection.

The Simulation hypothesis promoted by Nick Bostrom and others have suggests that our universe may be a computer simulation by aliens.

The Biocosm hypothesis and the Meduso-anthropic principle both suggest that natural selection has made the universe 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 our universe finely tuned.

Counter arguments to naturalistic explanations

Random chance, applied to a single and sole universe only begs the question as to why this universe could be so "lucky" so as to have precise conditions that support life at least at some place (the Earth) and time (within millions of years of the present). Multiple universes, bubble universe, and alien design are considered similarly speculative and unfalsifiable as are theistic explanations, making both a matter of "faith" that one chooses to believe. [11]

Religious opinions

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Creationism

As with theistic evolution, some individual scientists, theologians, and philosophers as well as certain religious groups have seized on the idea that providence or creation are responsible for fine-tuning. Intelligent design theories are not necessarily falsifiable, and thus some are reluctant to call intelligent design theories a "scientific" idea. Variants on this approach include:

Intelligent design

Proponents of Intelligent Design argue that certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection. The fine-tuned universe argument is a central 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 views

Most religions have some kind of account of the creation of the universe, although they generally differ in detail from the ones listed above. Some of these may be fully compatible with known scientific facts (notwithstanding their use of metaphysical ideas which are beyond the domain of science). For example scientist-theologians such as John Polkinghorne emphasise the implications of Anthropic Fine-Tuning within an orthodox Christian framework whilst fully accepting the scientific findings about Evolution and the age of the Universe. This is also the position of the Roman Catholic Church and of most Anglican theologians, of whom Alister McGrath is probably the most prolific in this area.[12] The Jewish physicist Gerald Schroeder argues that the apparent discrepancy between the "days" in Genesis and the billions of years in a scientific understanding are due to the differences in frames of reference. Many other religious creation views are either incompatible with, or indifferent to, scientific understandings. Other scientists with similar views are physicist Freeman Dyson and astronomer Owen Gingerich.

Counter argument to religious views

The "argument from imperfection" suggests that the if the universe were designed to be fine-tuned for life, it should be the best one possible and that evidence suggests that it is not.[13] In fact, most of the universe is highly hostile to life.

An implication of intelligent design may be that the designer is benevolent and, as such, the constants and structures of the universe are "life-friendly". However such intelligent designer may conceivably be malevolent.

(…) it is reasonable to conclude that God does not exist, since God is omnipotent, omniscient and perfectly good and thereby would not permit any gratuitous natural evil. But since gratuitous natural evils are precisely what we would expect if a malevolent spirit created the universe (…). If any spirit created the universe, it is malevolent, not benevolent.

— Quentin Smith, The Anthropic Coincidences, Evil and the Disconfirmation of Theism[14]

Bayesian arguments

A Bayesian probabilistic discussion by mathematician Michael Ikeda and astronomer William H. Jefferys in 2006 argues that the traditional reasoning about intelligent design from the presence of fine-tuning does not properly condition on the existence of life and is also based on an incorrect reversal of conditional probabilities.[15] They argue that it is an example of the prosecutor's fallacy, which in this form erroneously claims that if fine-tuning is rare in naturalistic universes, then a fine-tuned universe is unlikely to be naturalistic.

The philosopher of science Elliott Sober makes a similar argument (2004). Richard Swinburne reaches the opposite conclusion using Bayesian probability (Swinburne 1990).

In fiction

  • Stephen Baxter has written several novels and short stories in which the setting is an alternative universe with different physical laws. The most obvious example is Raft in which the force of gravity is a billion times stronger than in our universe. The novel, Time of the Manifold sequence includes the interesting concept that the universe itself is not perfectly tuned for life to exist and is still in the process of evolution itself. The climax of the book involves the destruction of the universe so that a new version, better suited to life, may replace it.
  • Robert J. Sawyer discusses the fine-tuned universe novel at length in his Hugo Award-nominated novel Calculating God (2000), which features an alien race that has develop a grand unified theory that includes these conclusions (presented in dialog):

"First, that this universe is not flat, but rather that it is closed: it did indeed start with a big bang and will expand for billions of years more -- but it will eventually collapse back down to a singularity in a big crunch.

"Second, that this current cycle of creation follows no more than eight previous big-bang/big-crunch oscillations -- we are not one in an infinitely long string of universes but, rather, are one of the very few that have ever existed."

"And the third provision of the grand unified theory is this: no parallel universes exist simultaneously with ours or any of the previous or subsequent ones, save virtually identical universes with exactly the same physical constants that split briefly from the current one then almost immediately reintegrate with it, thus accounting for certain quantum phenomenons.

"The math to prove all the foregoing is admittedly abstruse, although, ironically, the Wreeds intuitively came to an identical model. But the theory of everything made numerous predictions that have subsequently been confirmed experimentally; it has withstood every test it has been put to. And when we found that we could not retreat into the notion that this universe is one of a vast number, the argument for intelligent design became central to Forhilnor thought. Since this is one of a maximum of just nine universes that have ever existed, for it to have these highly improbable design parameters implies they were indeed chosen by an intelligence."[16]

Sawyer also explores the fine-tuned universe argument in his short story The Abdication of Pope Mary III, first published in Nature: International Weekly Journal of Science, July 6, 2000.

  • The Sphere Builders of Star Trek: Enterprise created the Delphic Expanse in an attempt to alter the physical laws of our universe to match those of their own parallel universe. Their form of life was not compatible with the current physical laws of our universe (as evidenced by their quickly decaying bodies), and thus needed to make said changes in order to conquer and live in our universe.
  • Author Neal Stephenson discussed the issue of fine-tuning in the conclusion to his essay In The Beginning Was The Command Line, speculating on what might happen if an all-powerful entity had access to a computer program that could generate universes with any desired set of properties.

The demiurge sits at his teletype, pounding out one command line after another, specifying the values of fundamental constants of physics:

universe -G 6.672e-11 -e 1.602e-19 -h 6.626e-34 -protonmass 1.673e-27....

and when he's finished typing out the command line, his right pinky hesitates above the ENTER key for an aeon or two, wondering what's going to happen; then down it comes--and the WHACK you hear is another Big Bang.[17]

Notes

  1. ^ Mark Isaak (ed.) (2005). "CI301: The Anthropic Principle". Index to Creationist Claims. TalkOrigins Archive. Retrieved 2007-10-31. {{cite web}}: |author= has generic name (help)
  2. ^ Larry Abbott, "The Mystery of the Cosmological Constant," Scientific American, vol. 3, no. 1 (1991): 78; quoted in Michael A Corey, The God Hypothesis: Discovering Divine Design in Our Goldilocks Universe Rowman and Littlefield, 2001.online
  3. ^ a b Is The Universe Fine-Tuned For Us? Victor J. Stenger, University of Colorado.
  4. ^ L. Susskind, The cosmic landscape: string theory and the illusion of intelligent design (Little, Brown, 2005).
  5. ^ William Lane Craig, "The Teleological Argument and the Anthropic Principle," [1]
  6. ^ See, e.g., Our place in the Multiverse Joseph Silk. Nature, Volume 443 Number 7108, September 14 2006.
  7. ^ See, e.g., Gerald Feinberg and Robert Shapiro, "A Puddlian Fable" in Huchingson, Religion and the Natural Sciences (1993), pp. 220-221
  8. ^ Parallel Worlds,2005, Michio Kaku, pp. 220-221
  9. ^ a b The Anthropic Coincidences
  10. ^ BBC - Science & Nature - Horizon - Parallel Universes - Transcript
  11. ^ Alvin Plantinga, Books & Culture, March/April 2007 Issue [2]
  12. ^ see eg his 3-volume Scientific Theology and his shorter book The Science of God
  13. ^ Avitel Pilpel, SKEPTIC, November 2007 Issue, p.18
  14. ^ The Anthropic Coincidences, Evil and the Disconfirmation of Theism
  15. ^ Jefferys The Anthropic Principle Does Not Support Supernaturalism, Michael Ikeda, Bill Jefferys
  16. ^ Robert J. Sawyer, Calculating God, Tor Books, New York 2000
  17. ^ In The Beginning Was The Command Line

References

See also

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