Paul Davies, "Chance or creation? Only the multiverse knows for sure" (2005)

Chance or creation? Only the multiverse knows for sure

Many cosmologists believe that what we have been calling “the universe” is nothing of the sort. Rather, it is just an infinitesimal component of a vast and elaborate system dubbed “the multiverse.” In this scheme, many of the laws of physics are demoted to mere bylaws, valid only in our own cosmic region. A God’s-eye-view of the multiverse would reveal countless bubbles of space, each featuring its own distinctive laws and initial conditions.
> <br> By Paul Davies
> <span class="dateText">(January 1, 2005)<span>

The multiverse is not an idle speculation, but a natural consequence of developments in fundamental physics and cosmology, such as the fashionable string theory and the so-called inflationary universe scenario. It has the backing of many eminent cosmologists, such as Martin Rees, Britain’s Astronomer Royal, and the Nobel Laureate Steven Weinberg. Nevertheless, some distinguished scientists vehemently oppose the idea, believing it to be a cop-out in the race for the holy grail of physics: a final, unified theory of all physical existence. The issue looks set to split the cosmology community as deeply and acrimoniously as the old steady-state versus big bang controversy.

 

Part of the reason passions are running so high is because the universe-multiverse debate touches on sensitive metaphysical issues like the role of the observer and the nature of physical law. It also affects philosophy and theology, because it concerns whether or not the universe is ingeniously — indeed, suspiciously — contrived.

The multiverse has frequently been invoked to slam the argument of the universe’s purposeful design by attributing the amazing cosmic bio-friendliness not to divine providence, but to a simple observer selection effect. If the laws of physics vary randomly from universe to universe, then very rarely, purely by chance, they will just happen to come out right for life. Since by definition we could not live in any of the numerous bio-hostile universes, it is no surprise that we find ourselves in one of the rare life-encouraging universes. Ironically though, cosmologists attracted to the God-evading qualities of the multiverse theory have themselves been accused of quasi-religious sentiment by anti-multiverse scientists, who are intent on writing observers out of the cosmic script entirely. They would prefer that the ultimate explanation for the laws of physics stem from a deep and elegant mathematical principle which makes no reference to life or mind.

While the insults fly between opposing scientific camps, it is important to assess whether the multiverse does in fact give a satisfactory account of the appearance of cosmic design anyway. One problem is that it has the air of a catch-all explanation that could account for almost anything. Furthermore, it still assumes the existence of laws of some sort, the origin of which remain unexplained. Max Tegmark has attempted to remove the latter obstacle by enlarging the multiverse to include all logically possible universes, including those described by weird and unfamiliar mathematics. The trouble with this “anything goes” philosophy is that there is no reason to stop with universes characterized by logic and mathematics. Why not consider all possible aesthetic systems, or all possible deities?

More seriously, one should also contemplate all possible virtual realities. The notion of a fake world simulated by some future supercomputing technology, containing conscious beings oblivious of their situation, has been popularized in The Matrix movies. Astonishingly, some scientists are prepared to take this scenario seriously and include all the fake universes too in the multiverse, in spite of the fact that such universes clearly satisfy the definition of being “designed.” Whether this is an absurd reading of the multiverse explanation, or a further, dizzying enlargement of our concept of physical reality, remains the subject of lively debate.

Paul Davies is a professor at the Australian Centre for Astrobiology at Macquarie University in Sydney. Most of his research has been in the area of quantum field theory in curved spacetime. He has investigated and discovered many quantum effects associated with black holes and the early stages of the big bang. He recently conducted research in the areas of quantum gravity, gravitational entropy, physics of complexity and foundations of quantum mechanics. He has authored and edited several books, including The Mind of God: The Scientific Basis for a Rational World, The Fifth Miracle: The Search for the Origin and Meaning of Life,  and God and the New Physics