In writing previously about Lawrence Krauss’s book, A Universe From Nothing: Why is There Something Rather Than Nothing? I called this the greatest question. Comes now Jim Holt’s book, Why Does the World Exist? Whereas Krauss’s was basically a physics book, Holt’s is mainly philosophical.
At the heart of the problem is what nothingness means (as the alternative to the Universe we’ve got, full of stuff). Holt spends much time on this, discussing the plausibility of nothingness via a process of subtraction from our cosmos of somethingness. Meantime Krauss described nothingness in such a way that applying physics to it could get you a Big Bang; he talks a lot about field theory and suchlike. But the trouble is that religious apologists can always say their nothingness (not even fields) is deeper than yours and requires a god to get something going. Of course, a “nothingness” that’s got a god in it ain’t no nothingness in my book and merely begs the question of where he came from. (As Dawkins says, a god capable of the trick would be so complex and improbable as to require an explanation even bigger than the one he supposedly provides.)
But Holt explains that the picture of our Universe leaping into being out of nothingness is actually somewhat misleading. The key point is that time itself (or, more accurately, space-time) is a feature of our Universe. “Before” the Big Bang there was neither space nor time. And I put “before” in quotes because there was no “before.” “Before” is a time concept, and if time began with the Big Bang, it’s incoherent to speak of anything “before” it. The Big Bang is a boundary, just as the edge of our curved space-time is a boundary, and it’s equally incoherent to speak of anything “beyond.”
Thus, to say the Universe is 13.7 billion years old is actually equivalent to saying it always existed. Not that you can go back an infinite number of years; you can’t. You can only go back 13.7 billion years. That’s all the time there’s been; “always” means 13.7 billion years.
The foregoing might seem to make the question, why the world exists, go away. Holt discusses one philosopher, Adolf Grunbaum, who does think existence is a non-question.
But I disagree. For all the agonizing over conceptualizing non-existence, I, in my simple-minded way, have no problem with it. Suppose the Big Bang had never happened. It was, after all, an event, and maybe a-la-Krauss it can be deemed inevitable, but still it’s possible to conceive the alternative. The Universe either exists or it doesn’t. Without a Big Bang, it doesn’t. Nothing, nada, maybe not even Krauss’s quantum fields (maybe). So the question doesn’t really go away: if there are two alternatives, why does one obtain rather than the other?
Indeed, as Holt observes, Occam’s Razor tells us that nothingness is far more likely than existence, since the theory of nothingness is the sine qua non of simplicity – it has no moving parts or arguably arbitrary components. Existence is full of them.
But a different way to approach the problem is to posit that the Big Bang was not a unique event. If it happened once, it’s entirely reasonable to suppose it’s happened over and over. One possibility is an oscillating universe – its expansion reverses and ends in a “big crunch” which rebounds in a fresh big bang. Another is the multiverse concept, that big bangs are natural events in any universe; and our own may be creating offspring universes, for example, out of the “singularities” at the hearts of black holes, where the laws of physics go haywire. In either of those models, “always” can become not just 13.7 billion years, but infinite, with no beginning to existence. But that of course still leaves the question of why this rather than eternal nothingness.
Meantime, if we accept Krauss’s tack, that the laws of physics, acting upon whatever void “preceded” the Big Bang, somehow account for its happening – where did those laws come from? Could they – like the law of gravity (its force being inversely proportional to the square of the distance between objects) – have been operative (or latent) even in a nothingness devoid of space or time? How so? And if so, couldn’t one object that a true nothingness wouldn’t even harbor laws of physics?
A multiverse could obviate this problem, since each daughter universe could be born with its own laws of physics (and parameters, like the electron’s weight), which could differ among them; you wouldn’t need to conceive of any pre-existing laws. This would also answer the “anthropomorphic” argument that our Universe’s parameters seem preternaturally fine-tuned to permit our existence. If there are many divergent Universes, it’s no wonder we find ourselves in the one where that’s possible.
A footnote is that, as Einstein showed, matter and energy are interchangeable. And gravity being negative energy, it balances out the positive energy incorporated in all the mass in the Universe. Thus the Universe’s total net energy is zero; which makes it somewhat easier, at least, to conceive its popping out of “nothing.” In simpler terms, 0 can be peeled apart into +1 and -1; so from nothing you can get two somethings. The ultimate free lunch, this has been called.
It helps too that our thinking of matter as “stuff” is also not exactly right. Aristotle theorized that the world consists of stuff plus structure. Now we know that matter is at least mostly empty space. And as we delve ever deeper into submicroscopics, it’s basically all structure and we actually can’t find any hard nuggets of stuff. What seems to be stuff turns out to be just artifacts of structure. That too makes somewhat more plausible a Universe bursting from “nothing.”
Nearing the end of the intellectual journey he traces, seeking an answer to the title question, Holt gives us several pages of logic which he claims resolve, to his own satisfaction, why the Universe must exist. It’s the one part of the book I actually skipped over. I felt sure it couldn’t be that simple, any more than St. Anselm’s famously concise “ontological argument” proves God’s existence.* This is not something we can solve with pure intellectualizing.
I recognize that much of this essay might strike a religious reader as mumbo-jumbo, like the doctrine of the Trinity sounds to an atheist. But here’s the difference. Theological theories are bald speculations not subject to correction by any information coming from reality. Science, in contrast, is an enterprise concerned with understanding reality based upon actual information we get from it, and developing as we get more. The standard model of physics, including the Big Bang, has been confirmed by predictions based upon it being borne out by observation — so far, at least (that’s how Einstein got his Nobel prize). Of course our understanding is a work in progress. But positing God as the explanation is a “Hail Mary” pass that evades the issue.
* 1) God is the greatest imaginable being; 2) A being that exists is greater than one who doesn’t; 3) Therefore God exists. Ha ha. The fallacy is that you’re talking not about God, but the idea of God. There’s no way thinking about something can prove it exists.