In recent years, as our deepening understanding of the delicate complexity of the universe continues unabated, Naturalists are increasingly turning to "multiverse" hypotheses to blunt or dodge the force of fine-tuning and teleological arguments for the existence of a Designer. Roughly, the idea is that, parallel to the universe we inhabit, there exists an infinite series of universes, each of which is different from our own in at least one respect. In the multiverse, every contingent possibility is instantiated in at least one universe. If it helps, the concept has been used for dramatic effect on the TV show, Sliders, and in The Hitchhikers Guide to the Galaxy. The multiverse is thought to undercut design arguments because while it is wildly improbable that our life-supporting universe should exist if there was only one shot at it, it is inevitable that our universe exist if every possible universe exists. (Yes, it begs the question of the necessary conditions for this meta-universe, but we'll leave that to the side.) There are mixed feelings about the multiverse hypothesis amongst skeptics and Naturalists. While it may be a stopgap against the implications of our apparently designed universe, it is an inescapably ironic move for the Naturalist to postulate a deus ex machina that is unobserved and, in principle, unobservable.

To be honest, postulating parallel universes strikes me as a desperate move, a textbook example of a Kuhnian, ad hoc supposition to save Naturalism in the face of powerful evidence to the contrary. To be sure, theism entails its own fantastic theses, but perhaps none as far-reaching and unsubstantiated as the multiverse. There are some smart people who believe in parallel universes, even some physicists who believe that in quantum physics we can detect interaction with a parallel universe. But even if we grant that this highly contested interpretation of quantum physics has merit, and grant that this interaction should not be understood as a mysterious feature of our own universe, this "scientific" evidence falls far short of establishing the panoply of universes required to undercut arguments for a Designer.

When faced with the fine-tuning of this wonderful universe of ours, if Naturalists make the move to a multiverse hypothesis, they bely a curious prejudice for things made of matter. The multiverse may be untestable, unobservable, unverifiable (sound familiar?) ... but at least, in theory, it's made of stuff. They are also making a noteworthy, if unintentional, concession. In turning to such a radical solution, there is an admission that in this universe there is, in fact, a striking appearance of design, or at least a colossal improbability, that demands an explanation.

Update: Since originally posting this clipping, Discover Magazine has published an excellent article by Tim Folger on multiverse theorizing: "Science's Alternative to an Intelligent Creator: the Multiverse Theory". In quite poetic prose, Folger states the problem well and surveys a number of efforts in theoretical science to substantiate the multiverse.

An Excerpt: A sublime cosmic mystery unfolds on a mild summer afternoon in Palo Alto, California... The day seems ordinary enough. Cyclists maneuver through traffic, and orange poppies bloom on dry brown hills near Linde’s office on the Stanford University campus. But everything here, right down to the photons lighting the scene after an eight-minute jaunt from the sun, bears witness to an extraordinary fact about the universe: Its basic properties are uncannily suited for life. Tweak the laws of physics in just about any way and — in this universe, anyway — life as we know it would not exist. ¶ Consider just two possible changes. Atoms consist of protons, neutrons, and electrons. If those protons were just 0.2 percent more massive than they actually are, they would be unstable and would decay into simpler particles. Atoms wouldn’t exist; neither would we. If gravity were slightly more powerful, the consequences would be nearly as grave. A beefed-up gravitational force would compress stars more tightly, making them smaller, hotter, and denser. Rather than surviving for billions of years, stars would burn through their fuel in a few million years, sputtering out long before life had a chance to evolve. There are many such examples of the universe’s life-friendly properties—so many, in fact, that physicists can’t dismiss them all as mere accidents. ¶ “We have a lot of really, really strange coincidences, and all of these coincidences are such that they make life possible,” Linde says. ¶ Physicists don’t like coincidences. They like even less the notion that life is somehow central to the universe, and yet recent discoveries are forcing them to confront that very idea. Life, it seems, is not an incidental component of the universe, burped up out of a random chemical brew on a lonely planet to endure for a few fleeting ticks of the cosmic clock. In some strange sense, it appears that we are not adapted to the universe; the universe is adapted to us. ¶ Call it a fluke, a mystery, a miracle. Or call it the biggest problem in physics. Short of invoking a benevolent creator, many physicists see only one possible explanation: Our universe may be but one of perhaps infinitely many universes in an inconceivably vast multi verse. Most of those universes are barren, but some, like ours, have conditions suitable for life.