by Jim Holt
I spent much of that weekend in the bathtub under the roof of the Athenaeum, contentedly reading, soaking, sipping claret obligingly brought up to me by the porter from the club’s cellar, and pondering. Winston Churchill would have approved.
THERE ARE TWO broad questions we can ask about the world: why it is, and how it is. Most of the thinkers I had encountered so far believed that the why question should come first. Once you know why the world is, they maintained, you’ll have a pretty good notion of how it is. Suppose, like John Leslie, or Plato and Leibniz before him, you believe that the world exists because it ought to exist. Then you would expect the world to be a very good world. And if the part of it you observed didn’t look especially good, you would conclude—again, like Leslie—that it must be just a tiny bit of a larger reality that, on the whole, was very good—infinitely good, in fact.
So one way of reasoning about the world is to go from why to how. But another, less obvious way is to move in the opposite direction. Suppose you look around at the world and notice that it has some special feature, one that marks it off from all of the other ways reality might have been. Perhaps, you might think, this peculiarity in how the world is could furnish a clue as to why the world is.
Going from how to why was, I discovered, the essence of Parfit’s approach. And his reversal of the usual explanatory vector made me see the mystery of existence in an entirely new light.
Think, Parfit begins, of all the different ways that reality could have turned out. One possible way, of course, is our own world—the universe that came into existence 14 billion years ago with the Big Bang. But reality might encompass more than just our world. There could be other worlds that exist in parallel with our own, even if we do not have direct access to them. And these worlds might be different in important respects from our world—in their histories, in their governing laws (or lack thereof), and in the nature of the substances that constitute them. Each of these individual worlds is what Parfit calls a “local” possibility. And the entire ensemble of individual worlds that might exist together adds up to a “cosmic” possibility.
“Cosmic possibilities,” Parfit says, “cover everything that ever exists, and are the different ways that the whole of reality might be. Only one such possibility can be actual, or the one that obtains. Local possibilities are the different ways that some part of reality, or local world, might be. If some local world exists, that leaves it open whether other worlds exist.”
So what sort of cosmic possibilities are there? Well, one cosmic possibility is that every conceivable world exists. Parfit calls this fullest of all realities the “All Worlds” possibility. At the other extreme is the cosmic possibility in which no worlds at all exist. This Parfit calls the “Null” possibility. In between the All Worlds possibility and the Null possibility range an infinity of intermediate cosmic possibilities. One of them is the possibility that all and only good worlds exist—that is, all worlds that are on the whole ethically better than nothing. This would be John Leslie’s “Axiarchic” possibility. Another cosmic possibility is the one in which our world and 57 other worlds similar but slightly different from it exist. One might call this the “58 Worlds” possibility. Another is that only worlds that conform to a certain set of physical laws exist—say, the laws of string theory. According to the current version of string theory, such worlds number on the order of 10 to the five-hundredth power, making up a cosmic ensemble that physicists call “the Landscape.” Still another cosmic possibility is that only those worlds that are devoid of consciousness exist. One might call this the “Zombie” possibility. And still another is that there are exactly seven worlds, each of a single color: respectively red, orange, yellow, green, blue, indigo, and violet. One might call this the “Spectrum” possibility.
The full range of such cosmic possibilities represents every way reality could have turned out. Even sheer nothingness is counted, in the form of the Null possibility. (Logical impossibilities, on the other hand, are not counted; no cosmic possibility includes a world of square circles or married bachelors.) And of all the possible ways reality could have turned out, one of them has to obtain.
Which raises two questions. Which of them does obtain? And why?
“These questions are connected,” Parfit goes on to observe. “If some possibility would be easier to explain, we have more reason to believe that this possibility obtains.”
The least puzzling of all of the cosmic possibilities, it would seem, is the Null possibility—that there is nothing at all. This is much the simplest possible reality, as Leibniz pointed out. It is also the only one that does not stand in need of a causal explanation. If there were no worlds at all, then no question would be raised as to what thing or force could have ushered those worlds into being.
But the Null possibility is evidently not the form reality chose to take. “In some way or another,” Parfit observes, “a Universe has managed to exist.”
And which is the least puzzling cosmic possibility that is consistent with the fact that our universe exists? That would be the All Worlds possibility: that all possible universes exist. “With every other cosmic possibility,” Parfit writes, “we have a further question. If ours is the only world, we can ask: ‘Out of all the possible worlds, why is this the one that exists?’ On any version of the Many Worlds Hypothesis, we have a similar question: ‘Why do just these worlds exist, with these elements and laws?’ But, if all these worlds exist, there is no such further question.”
The All Worlds possibility is thus the least arbitrary of the cosmic possibilities, since no local possibility is excluded. And this fullest of all possibilities could, for all we know, be the form that reality actually does take.
But what about the other cosmic possibilities? Well, if our world has a net goodness rating above zero, it might be part of the Axiarchic ensemble of worlds, whose existence would be the ethically best. Or if the laws governing our world turn out, in the final theory envisaged by Steven Weinberg, to be exceptionally elegant, then our world might be part of the most beautiful cosmic possibility. Or, if Schopenhauer and Woody Allen are right, our world might well be part of the worst cosmic possibility.
The point is that each of these cosmic possibilities has a special feature. The Null is the simplest, the All Worlds is the fullest, the Axiarchic is the best, and so on. Now, suppose that the cosmic possibility that actually obtains is also one that possesses such a special feature. Perhaps that is no coincidence. Perhaps that possibility obtains because it has this special feature. If that is the case, this special feature in effect chooses what reality is like. It is what Parfit calls “the Selector.”
Not every special feature a reality might have makes for a credible Selector. Suppose, for example, the 58 Worlds possibility mentioned earlier was how reality turned out. Now, the number 58 does have a special property: it is the smallest number that is the sum of seven different primes (2 + 3 + 5 + 7 + 11 + 13 + 17 = 58). But no one would imagine that this property could explain why reality turned out the way it did. It would be more reasonable to assume that the number of worlds merely happened to be 58. But features like best, fullest, simplest, most beautiful, and least arbitrary are different. If the cosmic possibility tapped to be reality had one of these features, it would be hard to think of this as simply a matter of chance. More likely, the cosmic possibility became reality because it had this feature.
But isn’t this use of “because” somewhat mysterious? Of course it is, Parfit admits. But even ordinary causation, he points out, is mysterious. Besides, he says, “if there is some explanation of the whole of reality, we should not expect this explanation to fit neatly into some familiar category. This extraordinary question may have an extraordinary answer.”
What Parfit had managed to do, I realized, was to reframe the mystery of existence in a way that made it vastly less mysterious. While everyone else was trying to bridge the unbridgeable gap between being and nothingness, he was running an ontological lottery. Or
was it more like a beauty contest—the Miss Cosmos Pageant? The field of contestants comprised all the different ways reality could have turned out—all the cosmic possibilities. And since reality has to be some way or another, one of these cosmic possibilities is bound to prevail, as a matter of logical necessity. There is no conceivable alternative, and hence no need for any sort of “hidden machinery” to ensure that a selection is made. So the Selector, in tipping the outcome, doesn’t exert any force or do any actual work.
But what, I wondered, if there is no Selector?
AFTER MY SOLITARY weekend of reading, brooding, soaking, and dozing, it was good to come down to the commodious dining room of the Athenaeum Club on Monday morning and see a couple of dozen young City of London types, nicely turned out in Savile Row bespoke suits and Turnbull & Asser shirts, at breakfast. It reminded me that there are other things (if not necessarily more important things) beyond all this metaphysical fiddle. I picked up a copy of the Daily Telegraph, sat down at a table by myself, and ordered a big greasy English breakfast of eggs and kippers and stewed tomatoes. Delicious. A couple of hours later, feeling more sated than I usually did at that time of day, I was boarding an Oxford-bound train at Paddington Station.
En route to Oxford, I continued to think about what the Selector for our world could possibly be. Clearly, it was not simplicity. For, if it had been, the outcome of the reality contest would surely have been the Null Possibility. And whatever else the west London suburbs and commercial areas my train was passing through at the moment might be—drab, dingy, dispiriting—they were not nothing.
As for Platonic goodness being the Selector, as John Leslie believed, I had long ago put that rather too sanguine notion behind me. So, by the way, had Parfit. “We may doubt that our world could be even the least good part of the best possible Universe,” he dismissively observed.
But if this world fails to be ethically distinguished, it does seem to be special in other ways. It displays orderly causal patterns. Moreover, the laws that govern it appear to be, on the deepest level, remarkably simple—so simple that, if Steven Weinberg is right, human scientists are today on the verge of discovering them. Surely these two features—causal orderliness and nomological simplicity—mark off the actual world from the great ruck of messy and complicated cosmic possibilities.
This sort of thinking had led Parfit to the tentative conclusion that there might be at least two “partial Selectors” for reality: being governed by laws, and possessing simple laws. And could there be still others that we have not yet noticed? Possibly. “But observation can take us only part of the way,” he observed. “If we can get further, that will have to be by pure reasoning.” Such reasoning aims at the highest principle governing reality—the same principle that physicists are trying to discover. Thus, said Parfit, “there is no clear boundary here between philosophy and science.”
Hello! The train is pulling into Oxford already, right at the prick of noon.
FROM THE TRAIN station it was just a short walk to the town center—a walk with which I was by now well familiar. “Come to All Souls College in the High Street at 1 p.m. and ask the Porter to call me from the lodge by the College gate,” Parfit had instructed me in his letter.
Since I had a little time to kill, I dropped into Blackwell’s on Broad Street, the best scholarly bookshop in the English-speaking world. I headed downstairs to the vast philosophy section, where, after browsing a bit, I found a wonderful book of photo-portraits of the greatest living philosophers, taken by a photographer named Steve Pyke. Parfit was among the subjects. His appearance was certainly striking: an elongated face, featured with thin lips, a granite nose, and wide pensive eyes, was surmounted by a luxuriant profusion of curly silver-white hair, which extended down the sides of his head almost to the level of his chin. Each photo was captioned with a personal statement by the philosopher who had posed for it. Parfit’s read, “What interests me most are the metaphysical questions whose answers can affect our emotions and have rational and moral significance. Why does the Universe exist? What makes us the same person throughout our lives? Do we have free will? Is time’s passage an illusion?”
A quarter of an hour later, I was peering through the rather forbidding gate of All Souls. THE COLLEGE IS CLOSED, announced one sign. QUIET PLEASE, said another. Beyond the gate, I could see a courtyard with two manicured rectangles of grass.
I made myself known to the college porter, who was dour of aspect, and waited as he rang up my host-to-be.
All Souls is a storied place. (“All Souls, no bodies,” says the wag.) One occasional visitor to All Souls when he was an Oxford undergraduate in the 1960s was Christopher Hitchens, who described it as “a florid antique shop that admitted no students and guarded only the exalted privileges of its ‘fellows,’ a den of iniquity to every egalitarian and a place where silver candelabras and goblets adorned a nightly debauch of venison and port.” The fellows of All Souls, seventy-six in number, are selected from the most august ranks of the British academy and public life. Having no tutoring duties, they are free to pursue, amid sumptuous surroundings, a life of pure scholarship and speculative thought—relieved, perhaps, by internal politics and gossip. Parfit, somewhat unusually, had spent the whole of his career there, having been elected a “prize fellow” in 1967, fresh out of his undergraduate days at Balliol College.
And here he was, bounding toward me diagonally across the quadrangle—a tall, gangling, smiling fellow, whose unruly mop of argent tresses fulfilled the promise of the photo I had just seen. He was wearing a bright-red tie, which rhymed with his rather rubicund face. We shook hands and exchanged greetings. I offered to take him to one of the better restaurants out on the High Street for a long wine-soaked lunch.
“No,” he said, “I’m giving you lunch.”
He led me inside the college. “This is the best view in all of Oxford,” he said, gesturing out a large window toward Radcliffe Camera, the old library of Oxford. “The dome is by Hawksmoor!”
I remembered having heard that Parfit was a keen architectural photographer.
Lunch was being served to the fellows of All Souls in “the Buttery,” a Gothic dining room with a lofty coffered ceiling and highly resonant acoustics. Parfit invited me to help myself at the buffet, where I filled my plate with avocado salad and bread. We sat down to eat and talk.
Parfit told me about his life. He had been very pious as a young child, he said, but he gave up religion at the age of eight or nine. He remembered, when looking at pictures of the crucifixion, how he felt the most pity for the bad thief—“because, unlike Jesus and the good thief, he’s going to hell after he suffers and dies on the cross.”
Then he talked about mathematics, at which, he said, he was terrible. He expressed amazement that mathematics could be so complicated. A mathematician had told him that 80 percent of mathematics was about infinity. And he was horrified to learn that there was more than one infinity!
Even though his father wanted him to be a scientist, Parfit continued, he decided that he would become a philosopher. He hated the “scientizing” of philosophy, the main influences behind which, he felt, were Quine and Wittgenstein. He also hated the “naturalizing” of epistemology—the idea that the project of justifying our knowledge should be taken away from philosophers and given to cognitive scientists.
Then the talk turned to moral philosophy, which, he told me, was his main interest at the moment. Unlike many moral philosophers these days, he said, he believed that we have objective reasons to be moral, reasons that do not depend on our inclinations—adding that he would be “embarrassed even to have to defend that claim before a non-university audience.” He was appalled, he said, at some of the crazy views that contemporary philosophers had argued for, like the view that only desires can give rise to reasons.
Parfit winced, as if in pain, when mentioning such distasteful views, and often flung his arms toward the coffered ceiling in exasperation. He was equally animated when putting fo
rth the views that he favored, leaning close to me, grinning, and vigorously nodding.
When lunch was finished, we retired into an adjoining parlor to have coffee by the fireplace and talk about why there is Something rather than Nothing.
PARFIT, AS I mentioned earlier, had declined to be quoted at length on the matter. He did, however, say that he would answer my questions with a brief affirmative or negative reply. And I had two main questions, one easy and one hard.
The easy one had to do with nothingness. Parfit clearly believed that nothingness was a logically coherent idea. Indeed, he thought it was one of the ways reality could have turned out. “It might have been true,” he had written, “that nothing ever existed: no minds, no atoms, no space, no time.” Nothingness was therefore included among his cosmic possibilities, in the form of the Null possibility.
But was nothingness also a local possibility? That is, could it coexist with a world of being?
The philosopher Robert Nozick, for one, had thought that it could. If reality was as full as possible, encompassing every conceivable world, then one of those worlds would perforce consist of absolutely nothing. That, at least, was what Nozick believed. So the question Why is there something rather than nothing? on his way of thinking, might have a simple answer: There isn’t. There’s both.
Nozick’s reasoning has convinced some scientists, including his onetime Harvard student, the string theorist Brian Greene. “In the Ultimate Multiverse,” Greene has written, “a universe consisting of nothing does exist.” Again, reality embraces both something and nothing.
And, from a somewhat different angle, Jean-Paul Sartre agreed, declaring that “Nothingness haunts Being.”