You are special.
Don't worry, this is not the start of yet another Joel Osteen sermon. I mean only that your existence, itself a wildly improbable fact, increasingly seems to be the only peg on which cosmologists can hang the existence of our Universe.
Oh, and not just you, by the way. I'm special, too. All of us observers capable of wondering why we are here are special, because we contribute to what is known as the Anthropic Principle. Here's the nub of it, given by Stephen Hawking and a colleague in 1973: "The answer to the question 'why is the universe [the way it is]?' is 'because we are here.'"
There's something odd about that. As the cosmologist George F.R. Ellis notes, the Anthropic Principle sends the arrow of causation winging, feathers first, back to the bow. It declares, to paraphrase DesCartes, "I think, therefore the Multiverse."
Of course, those were the days before Hawking got rich and famous, in part by ending his bestseller A Brief History of Time with this catchy phrase: "for then we should know the mind of God."
Much has happened since then. Hawking has famously declared that we don't need God to explain the existence of the Universe, and less famously he's come out as an anti-realist. The best we can do, the cosmologist says, is to frame model-dependent views of reality. Hawking recently celebrated his 70th birthday, and on the occasion he clarified his views:
The origin of the universe can be explained by the laws of physics, without any need for miracles or Divine intervention. These laws predict that the universe was spontaneously created out of nothing in a rapidly expanding state. ...Our best bet for a theory of everything is M-theory [an extension of string theory].
One prediction of M-theory is that there are many different universes, with different values for the physical constants. This might explain why the physical constants we measure seem fine-tuned to the values required for life to exist. It is no surprise that we observe the physical constants to be finely-tuned. If they weren't, we wouldn't be here to observe them.
Hawking may be correct, but notice that this formulation of the so-called Weak Anthropic Principle doesn't really satisfy our curiosity. Why in the world should "nothing" have laws associated with it that give rise to spontaneous generation of the universe? Physicist Lawrence Krauss has just published a book on this very question. Krauss is worth reading (or hearing), but the argument he makes is, so far as I can judge, a book-length elaboration of the one Hawking makes above.
"Nothing" he writes,"in this case, no space, no time, no anything! -- is unstable." But he doesn't quite mean the absence of "anything." Krauss posits that the instability is generated by existence of the laws of physics -- in particular quantum gravity. Physicist Sean Carroll has put the position succinctly: "There is a chain of explanations concerning things that happen in the universe, which ultimately reaches to the fundamental laws of nature and stops."
Are the laws of physics fundamental givens? Or is the assertion that something can derive from nothing a logical absurdity? To pose such questions is to invite an exchange of verbal artillery between fervent apologists and exasperated atheists. I want to hold up a flag of truce and entreat all sides to climb out of their trenches.
In the search for answers, there is no reason to stop at M-theory, which is not strictly speaking a theory at all but an ill-defined speculation about how string theory, itself a speculation about quantum gravity, may cohere. To be sure, mathematics, which has often proven a reliable guide, waves its hands in that direction, but it might be fooling. Nature has often surprised even the greatest of physicists.
For instance: when Hawking first wrote about the Anthropic Principle, he and other cosmologists were focused on why gravity is weak enough to allow the Universe to expand for billions of years yet just strong enough to allow galaxies, stars, and planetary systems to form. At the time they thought its tuning had a tolerance of about 0.5 percent. Since then, however, physicists have been astonished to find that the Cosmological Constant -- the mysterious pushback that just ever-so-slightly counters gravity's inward rush -- is just strong enough, no more and no less, to a precision of more than a hundred decimal places. No one has been able to deduce any physical reason why it should be as it is. The Anthropic Principle is here to stay.
So, is that a sign of Divine creation? Some see it that way, but like so much else in our Universe on close examination it fails to support the hypothesis of intelligent design. If we are the aim, it makes no sense to inflate a Universe to at least 46 billion light years in size, stud it with hundreds of billions of galaxies containing hundreds of billions of stars apiece, and then pump it full of energy that will eventually tear the whole thing apart. And yet that is what seems to be happening before our eyes.
Indeed, the Universe, as science has revealed it, bears little resemblance to the description of Divine creation in various Scriptures. Only the most fanciful interpretations and strenuous apologetics can align Scriptures with science, and even then they fail to explain everything from dark energy to wave-particle duality to the periodic bombardment of the Earth by huge bits of rubble left over from the formation of the solar system.
Scientists, it must be said, are not necessarily hostile to religion. But the science-religion controversy has come to dominate the discourse on cosmic origins in ways that may be detrimental to the search for truth. Hawking, Krauss, and many others state their case for laws as the cause in direct opposition to Divine creation -- as if these were the only two possibilities. They are not.
To run just one more flag up the pole, it may be that the Universe we inhabit is a simulation -- one gigantic holodeck, running for purposes we cannot fathom. I doubt that is true, but the proposition is entirely consistent with all observations to date.
I think there are more interesting and fruitful possibilities to consider. I intend to do so in months to come, and I would invite readers to share their ideas. If we tiptoe past the Yaweh or Law Way feud, might we stumble closer to truth? Or better yet, might we construct a model that is both consistent with the evidence and more beneficial than either of those shopworn choices?