Talking to many members of the scientific community, one easily gets the impression that the multiverse model is a done deal, the ultimate reality. Undoubtedly the growing popularity of the multiverse idea will spill over into the popular culture -- especially when associated with names such as Stephen Hawking. (See "Does Hawking Believe In Multiple Universes?") So how is a Christian to respond?
It is important to realize that the multiverse proposal rests entirely on theoretical calculations (see "What is the Multiverse?" for more background). Although theoretical calculations play an integral role in developing successful scientific models, many models that look good on paper end up in the trash bin when confronted with hard experimental and/or observational evidence. Even given the theoretical modeling, the multiverse concept relies on additional speculation. Distinguished cosmologist Alan Guth goes so far as to assert that the multiverse is "speculation squared."1
One currently testable aspect of the multiverse model provides further reason to doubt its validity. In a book review published in Nature,2 George Ellis notes that in a multiverse, the geometry of this universe will be open. In more technical terms, the total density parameter, Ω, of an open universe will be less than one. However, the best measurements for our universe have Ωtotal = 1.02 +/- 0.02 (in other words, one or greater). Multiverse supporters believe that this marginally negative result will disappear as more precise measurements are made, but it is not encouraging when the first tests of a model tend toward falsification. Beyond this one test, no experimental evidence exists that would distinguish a multiverse from a universe. Until such evidence exists, nothing should compel a scientist -- or a nonscientist -- to accept a multiverse model as the final word.
On a more philosophical note, the reason many in the scientific community gravitate toward multiverse explanations is because they view completely naturalistic models as inherently more favorable than models invoking supernatural causation. This motivation appears to drive multiverse thinking because all multiverse models can be recast as a single universe. However, since multiverse models seem to provide a naturalistic explanation for the tremendous fine-tuning evident in this universe, some scientists tend to favor them over universe models.
Interestingly, it appears that many multiverse models redefine the term natural. Not too long ago the natural realm encompassed all space, time, matter, energy, and the physical laws associated with this universe. Anything beyond, by definition, was considered supernatural. However, all multiverse models assume a reality beyond the space, time, matter, energy, and physical laws of this universe. Thus, while multiverse enthusiasts would characterize their models as naturalistic, these models actually invoke supernatural or metaphysical features.
As Hugh Ross highlights, those gravitating toward multiverse models commit a form of the gambler's fallacy.3 Upon seeing the immense fine-tuning of this universe, they assume the existence of a large number of universes beyond ours which exhibit no fine-tuning. However, the scientific community currently has no way of knowing whether these alternate universes exist or if they differ from this universe. A better approach would be to look more closely at this universe and see if the evidence for fine-tuning increases as scientific understanding advances. If so, that increased evidence would argue more powerfully for a Designer who created and maintains this universe. Unfortunately, many people would rather gamble than embrace the evidence.
George Ellis summarizes the multiverse hypothesis by quoting Scripture (which also indicates that faith follows the evidence): "The multiverse situation seems to fit St. Paul's description: 'Faith is the substance of things hoped for, the evidence of things not seen.' In this case, it is faith that enormous extrapolations from tested physics are correct; hope that correct hints as to the way things really are have been identified from all the possibilities, and that the present marginal evidence to the contrary will go away."4
- Hugh Ross, The Fingerprint of God (Orange, CA: Promise Publishing, 1991), 113.
- George Ellis, "Physics Ain't What It Used To Be," Nature 438 (2005): 739-40. http://www.nature.com/nature/journal/v438/n7069/full/438739a.html
- Hugh Ross, The Creator and the Cosmos, 3rd ed. (Colorado Springs, CO: NavPress, 2001), 172-73.
- Ellis, "Physics Ain't What It Used To Be," 740.