Is God in the details? - religion, politics and physics

Reason, July, 1999 by Kenneth Silber

According to theories of the multiverse, the Big Bang was not a unique event. Instead, numerous "big bangs" have occurred - and continue to do so, in regions beyond our observational horizon. Each "bang" leads to a new universe, one bubble in a vast froth of bubbles. (One might object that the "universe" by definition is everything that exists, but its expanded scope if such theories are correct has given rise to the "universe/multiverse" terminology.) Different universes contain different combinations of forces and particles. If the range of combinations that support life is narrow, then the multiverse might be littered with uninhabited bubbles. But in at least one universe, the "constants" are suitable for carbon-based life.

The latter may be just a matter of chance. Given enough universes, sooner or later one is likely to hit upon the "right" combination for life (even assuming only one type of life is possible). But there may be more to it than that. Consider the theory of "cosmological natural selection" proposed by Penn State physicist Lee Smolin and detailed in his 1997 book The Life of the Cosmos. In this theory, our universe emerged from a black hole in a previous universe; moreover, each black hole in our universe (and other universes) generates yet another universe. Universes that produce lots of black holes therefore have more "progeny" than universes that don't. The laws of physics are reshuffled slightly with each black hole, and increasingly the multiverse is dominated by universes whose laws are "fine-tuned" to produce black holes.

So what? Well, black holes are formed when massive stars collapse. Stars are massive if they contain heavy elements - elements such as carbon. The selection process thus gives rise to universes such as our own, where carbon and other heavy elements are available as the building material for life.

In God: The Evidence, Glynn dismisses all multiple-universe theories, including Smolin's. These, he argues, are contrivances produced by "secular-minded scientists" to explain away the evidence for design. Glynn writes that "some scientists have speculated that there may exist billions of 'parallel' universes - which, mind you, we will never he able to detect - of which ours just happens to be one. If there were billions of invisible universes, then the series of miraculous coincidences that produced life in this one might not seem so unlikely." Such theories, according to Glynn, are "reminiscent of medieval theologians' speculations about the number of angels that could dance on the head of a pin."

But is the multiverse so far-fetched? The Big Bang seems to have occurred under conditions of extremely high density; similar conditions occur throughout our universe - in black holes. Similarly, Stanford cosmologist Andrei Linde argues that the fast inflation of the early cosmos - which requires merely a small region of curved space, or "false vacuum," to get started - implies a "self-reproducing" universe. The assumption that there are not multiple universes seems unwarranted by current evidence. Says Stenger: "There's no law of any kind that we know that says this could only have happened once. In fact, you'd have to invent a law of nature to explain why there was only one universe."