Published in Skeptical Inquirer Vol. 23, No. 4, July/August 1999.
Posted September 9, 2002
Poking out of the noise
Interpreting the coincidences
The natural scenario
Claims that scientists have uncovered supernatural purpose to the universe have been widely reported recently in the media. The so-called anthropic coincidences, in which the constants of nature seem to be extraordinarily fine-tuned for the production of life, are taken as evidence. However, no such interpretation can be found in scientific literature. All we currently know from fundamental physics and cosmology remains consistent with a universe that evolved by purely natural processes.
For about a decade now, an increasing number of scientists and theologians have been asserting, in popular articles and books, that they can detect a signal of cosmic purpose poking its head out of the noisy data of physics and cosmology (see, for example, Swinburne 1990, Ellis 1993, Ross 1995). This claim has been widely reported in the media (see, for example, Begley 1998, Easterbrook 1998), perhaps misleading lay people into thinking that some kind of new scientific consensus is developing in support of supernatural beliefs. In fact, none of this purported evidence can be found in the pages of scientific journals, which continue to operate within a framework in which all physical phenomena are assumed natural.
As the argument goes, the data are said to reveal a universe that is exquisitely fine-tuned for the production of life. This precise balancing act is claimed to be a highly unlikely result of mindless chance. An intelligent, purposeful, and indeed personal Creator must have made things the way they are.
As cosmologist and Quaker George Ellis explains it: "The symmetries and delicate balances we observe require an extraordinary coherence of conditions and cooperation of laws and effects, suggesting that in some sense they have been purposefully designed" (Ellis 1993: 97). Others have been less restrained in insisting that God is now required by the data and that this God must be the God of the Christian Bible (see, for example, Ross 1995).
The fine-tuning argument is based on the fact that earthly life is very sensitive to the values of several fundamental physical constants. Making the tiniest change in any of these, and life as we know it would not exist. The delicate connections between physical constants and life are called the anthropic coincidences (Carter 1974, Barrow and Tipler 1986). The name is a misnomer. Human life is not singled out in any special way. At most, the coincidences show that the production of carbon and the other elements that make earthly life possible required a sensitive balance of physical parameters.
For example, if the gravitational attraction between protons in stars had not been many orders of magnitude weaker than their electrical repulsion, stars would have collapsed long before nuclear processes could build up the chemical periodic table from the original hydrogen and deuterium. Furthermore, the element-synthesizing reactions in stars depend sensitively on the properties and abundances of deuterium and helium produced in the early universe. Deuterium would not exist if the neutron-proton mass difference were just slightly displaced from its actual value; neutrons, unstable in a free state, were stored in deuterium for their later use in building the elements.
The existing relative abundances of hydrogen and helium also implies a close balance of the relative strengths of the gravitational and weak nuclear forces. A slightly stronger weak force and the universe would be 100 percent hydrogen as all neutrons decayed away before assembling into deuterium and helium. A slightly weaker weak force and we would have a universe that is 100 percent helium; in that case neutrons would not have decayed and left the excess of protons that formed hydrogen. Neither of these extremes would have allowed for the existence of stars and life, as we know it, based on carbon chemistry. Barrow and Tipler (1986) list many other such "coincidences," some remarkable, others somewhat strained.
The interpretation of the anthropic coincidences in terms of purposeful design should be recognized as yet another variant of the ancient argument from design that has appeared in many different forms over the ages. The anthropic design argument asks: how can the universe possibly have obtained the unique set of physical constants it has, so exquisitely fine-tuned for life as they are, except by purposeful design--design with life and perhaps humanity in mind?
This argument, however, has at least one fatal flaw. It makes the wholly unwarranted assumption that only one type of life is possible --the particular form of carbon-based life we have here on earth. Even if this is an unlikely result of chance, some form of life could still be a likely result. It is like arguing that a particular card hand is so improbable that it must have been foreordained.
Based on recent studies in the sciences of complexity and "Artificial Life" computer simulations, sufficient complexity and long life appear to be primary conditions for a universe to contain some form of reproducing, evolving structures. This can happen with a wide range of physical parameters, as has been demonstrated (Stenger 1995). The fine-tuners have no basis in current knowledge for assuming that life is impossible except for a very narrow, improbable range of parameters.
Amusingly, the new cosmic creationists contradict the traditional design argument of the biological creationists, that the universe is so uncongenial to life that life could not have evolved naturally. The new creationists now tell us that the universe is so congenial to life that the universe could not have evolved naturally.
Since all scientific explanations until now have been natural, then it would seem that the first step, before asserting purposeful design, is to seek a natural explanation for the anthropic coincidences. Such a quest would avoid the invocation of supernatural agency until it is absolutely required by the data.
For almost two decades, the inflationary big bang has been the standard model of cosmology (Guth 1981, 1997; Linde 1987, 1990, 1994). We keep hearing, again from the unreliable popular media, that the big bang being is in trouble and the inflationary model is dead. In fact, no viable substitute has been proposed that has near the equivalent explanatory power.
The inflationary big bang offers a plausible, natural scenario for the uncaused origin and evolution of the universe, including the formation of order and structure--without the violation of any laws of physics. These laws themselves are now understood far more deeply than before, and we are beginning to grasp how they too could have come about naturally. The natural scenario I will describe here has not yet risen to the exalted status of a scientific theory. However, the fact that it is consistent will all current knowledge and cannot be ruled out at this time, demonstrates that no rational basis exists for introducing the added hypothesis of supernatural creation. Such a hypothesis is simply not required by the data.
According to the proposed natural 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 a bubble of false vacuum is curved, or warped, and a small amount of energy is stored in that curvature, like the potential energy of 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 and original references, see Stenger 1990). As the bubble expanded, its curvature energy transformed (naturally) into matter and radiation. Inflation stopped, and the more linear big bang expansion we now experience commenced. As the universe cooled, its structure spontaneously froze out--just as formless water vapor freezes into snowflakes whose unique and complex patterns arise from a combination of symmetry and randomness.
In our universe, the first galaxies began to assemble after about a billion years, eventually evolving into stable systems where stars could live out their lives and populate the interstellar medium with the complex chemical elements such as carbon needed for the formation of life.
So how did our universe happen to be so "fine-tuned" as to produce 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 life of some sort could have happened whatever form the universe took--however the crystals on the arm of the snowflake happened to get arranged by chance.
If we have no reason to assume ours is the only life form, we also have no reason to assume that ours is the only universe. Many universes can exist, with all possible combinations of physical laws and constants. In that case, we just happen to be in the particular one that was suited for the evolution of our form of life. When cosmologists refer to the anthropic principle, this is all they usually mean. Since we live in this universe, we can assume it possesses qualities suitable for our existence. Humans evolved eyes sensitive to the region of electromagnetic spectrum from red to violet because the atmosphere is transparent in that range. Yet some would have us think that the causal action was the opposite, that the atmosphere of the earth was designed to be transparent from red to violet because human eyes are sensitive in that range. Stronger versions of the anthropic principle, which assert that the universe is somehow actually required to produce intelligent "information-processing systems" (Barrow and Tipler 1986), are not taken seriously by most scientists or philosophers.
The existence of many universes is consistent with all we know about physics and cosmology (Smith 1990, Smolin 1992, 1997, Linde 1994, Tegmark 1997). Some theologians and scientists dismiss the notion as a gross violation of Occam's razor(see, for example, Swinburne 1990). It is not. No new hypothesis is needed to consider multiple universes. In fact, it takes an added hypothesis to rule them out-- a super law of nature that says only one universe can exist. But we know of no such law, so we would violate Occam's razor to insist on only one universe. Another way to express this is with lines from T. H. White's The Once and Future King: "Everything not forbidden is compulsory."
The hundred billion galaxies of our visible universe, each with a hundred billion stars, is but a grain of sand on the Sahara that exists beyond our horizon, grown out of that single, original bubble of false vacuum. An endless number of such bubbles can very well exist, each itself nothing but a grain of sand on the Sahara of all existence. On such a Sahara, nothing is too improbable to have happened by chance.
I have greatly benefitted from discussions on this subject with Ricardo Aler Mur, Samantha Atkins, John Chalmers, Scott Dalton, Keith Douglas, Ron Ebert, Simon Ewins, Jim Humphreys, Bill Jefferys, Kenneth Porter, Wayne Spencer, Quentin Smith, and Ed Weinmann.
This is a much abridged version of a longer essay entitled The Anthropic Coincidences: A Natural Explanation to appear in the British Skeptical Intelligencer.
Barrow, John D. and Frank J. Tipler 1986. The Anthropic Cosmological Principle. Oxford: Oxford University Press.
Begley, Sharon 1998. "Science Finds God." Newsweek July 20, 46.
Carter, Brandon 1974. "Large Number Coincidences and the Anthropic Principle in Cosmology," in M. S. Longair, ed., Confrontation of Cosmological Theory with Astronomical Data. Dordrecht: Reidel, 291-298, Reprinted in Leslie 1990.
Easterbrook, Greg 1998. "Science Sees the Light." The New Republic October 12, 24-29.
Ellis, George 1993. Before the Beginning: Cosmology Explained. London, New York: Boyars/Bowerdean.
Guth, A. 1981. "Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems," Physical Review D23, 347-356.
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Linde, Andre 1994. "The Self-Reproducing Inflationary Universe." Scientific American, November, 48-55.
Ross, Hugh 1995. The Creator and the Cosmos: How the Greatest Scientific Discoveries of the Century Reveal God. Colorado Springs: Navpress.
Smolin, Lee 1992. "Did the universe evolve?" Classical and Quantum Gravity 9, 173-191.
Smolin, Lee 1997. The Life of the Cosmos. Oxford: Oxford University Press.
Smith, Quentin 1990. "A Natural Explanation of the Existence and Laws of Our Universe." Australasian Journal of Philosophy 68, 22-43.
Stenger, Victor J. 1988. Not By Design: The Origin of the Universe. Buffalo NY: Prometheus.
Stenger, Victor J. 1990. "The Universe: The Ultimate Free Lunch." European Journal of Physics 11, 236.
Stenger, Victor J. 1995. The Unconscious Quantum: Metaphysics in Modern Physics and Cosmology. Amherst, N. Y.: Prometheus Books.
Swinburne, Richard 1990. "Argument from the Fine-Tuning of the Universe" in Leslie (1990: 154-173).
Tegmark, Max 1997. "Is 'the theory of everything' merely the ultimate ensemble theory?" To be published in Annals of Physics.
Victor J. Stenger is a Professor of Physics at the University of Hawaii. He is the author of Not By Design: The Origin of the Universe (Prometheus Books, 1988), Physics and Psychics: The Search for a World Beyond the Senses (Prometheus Books, 1990), and The Unconscious Quantum: Metaphysics in Modern Physics and Cosmology (Prometheus Books, 1995).
This article first appeared at Victor J. Stenger's web site.