Victor J. Stenger, "Davies's third way" (2005)

Physicist and prolific writer Paul Davies does not like any of the solutions usually proffered for the anthropic coincidences—the apparent fine-tuning of the constants of physics that seems necessary for life as we know it. This is also often referred to as the anthropic principle. As described in a 2003 talk at Stanford, the 1995 Templeton Prize winner regards the cosmic designer explanation, favored by religious believers, to be ad hoc and explaining everything while nothing.

Davies also sees problems with the multiverse explanation, favored by many scientists, in which multiple universes exist—perhaps an infinite number—and we just happen to live in the one suitable for us. He also regards this as explaining everything while explaining nothing. In fact, since everything can happen with an infinity of choices, a subset of universes is bound to exist in which at least one civilization would be able to create virtual worlds, as in the movie The Matrix. We could be living in such a world, which is then ontologically equivalent to the traditional designer/creator Deity. (Davies acknowledges that others have made the same suggestion).

Despite his disparagement of the multiverse, however, Davies suggests some differences between the kinds of universes we might expect from the multiverse hypothesis compared to that of a cosmic designer.

Davies argues that an observable universe within the multiverse occupies only a tiny fraction of parameter space so if the parameters of our universe were chosen purely by chance, then we would expect it to be near the limit of the range of bio-friendliness or what Davies calls, "minimal biophilicity." An intelligently designed universe, on the other hand, should be optimally biophilic.

So which is it, for our universe? In fact, our universe hardly looks very friendly to life. Only one planet in our solar system has a thriving form of life. The discovery of primitive life on Mars or Titan would not change that. The majority of stars are found in multiple stars systems, which implies highly irregular orbits and thus extreme ranges in conditions inimical to life. Of course, a far more robust form of life than our own might have developed in these systems, but we have only our extremely sensitive earthly life to judge by.

Furthermore, if the universe were bio-friendly, you would think it would not be so wasteful of time, space, and matter. Life would be expected to develop quickly, with carbon and the other elements of life already present in the early universe—not simply the afterthought of billions of years of stellar evolution. An optimally biophilic universe would not be expected to have life confined to tiny points in space separated by such great distances as to make exchange virtually impossible. And, if life is an important part of the universe, then its basic ingredients should be a major component. Instead, atoms comprise less than a tenth of one percent of the mass of the universe. Photons outnumber atoms by a factor of a billion. Finally, a life-friendly universe should exhibit far more order than ours, in which the deviation from random thermal motion is only one part in a hundred thousand.

So, right now, the data would seem to favor the multiverse hypothesis — or that of a not-very-intelligent designer.

Davies proposes an alternative explanation for the coincidences he calls the "Third Way." He suggests a life principle is "written into the laws of physics" or "built into the nature of the universe."

Of course, nowhere in current physics, chemistry, or biology do we see any sign of a fundamental life principle. Davies speculates, "a felicitous mix of law and chance might be generalised to cosmology, producing directional evolution from simple states, through complex, to life and mind." He mentions that others share this notion, notably Christian de Duve and Stuart Kauffman.

These authors all seem to view the life principle as some previously unrecognized, holistic, teleological law of nature. Theologians, such as Nancey Murphy, who admit that the notion of a separate soul and body is no longer viable given the evidence from neuroscience, have termed this notion "nonreductive physicalism." They think they can find a place for God and the soul therein.

However, computer simulations indicate that complexity evolves from simplicity by familiar, purely reductive physical processes without the aid of any overarching holistic guiding principle. The life principle, if it exists, may be one of the "emergent" principles found in chaos and complexity theory, which arise naturally from the nonlinear, dissipative, but still purely local interactions of material particles. These cannot be called new, fundamental laws of physics since they derive from already exiting laws.

Finally I would like to comment on one of the parameters that is always mentioned as an example of fine-tuning, the ratio of the strengths of the electromagnetic and gravitational forces, which is 1039. If gravity were not so comparatively weak, stars would collapse long before life had time to evolve. Back in 1919, physicist Hermann Weyl wondered where this number came from, intuitively feeling that the two forces should "naturally" be about the same strength. This was the first anthropic coincidence.

However, we now know that the strengths of the various forces are not constant but vary with energy or temperature. The forces probably all started equal and then separated as the universe cooled by a process called spontaneous symmetry breaking. Life had to simply wait for gravity to weaken sufficiently so that long-live stars could form.

Perhaps any random universe, regardless of its properties, will naturally develop at least some tiny pockets of complexity within a vast sea of randomness, which is just what we see in our universe. Perhaps we do not need either a designer or multiple universes to explain that fact.

Victor J. Stenger is professor emeritus of physics and astronomy at the University of Hawaii and adjunct professor of philosophy at the University of Colorado.