such was his conviction. In fact, if we look at the matter empirically—the way modern, scientifically minded people ought to—we’d find that the existence of a world is very much to be expected. As Grünbaum himself put it, “What could possibly be more commonplace empirically than that something or other does exist?”
Here was a man who thought Why is there something rather than nothing? was as much of a cheat as the question When did you stop beating your wife?
LATER THAT DAY, as I made my way across the bosky campus of the University of Pittsburgh toward my next rendezvous with Grünbaum, I was determined to champion the mystery of existence and the ontological claims of Nothingness. His office was atop the Cathedral of Learning—which, I was informed, was the tallest academic structure in the Western Hemisphere. It looked like an amputated and monstrously gigantified spire of a Gothic church. Entering the lobby, with its ribbed groin vaulting, I looked instinctively for a knave, an apse, an altar. But this was a secular cathedral, devoted not to the worship of some deity but to the pursuit of knowledge. All I saw instead was a bank of elevators. I took one of them to the twenty-fifth floor, where my mentor-turned-interlocutor was waiting for me.
After some small talk about psychoanalysis, I asked him whether he would be willing to concede that the concept of nothingness at least made sense. Isn’t it possible that, instead of the world we see around us, there might have been nothing at all?
“That’s something I’ve suffered through and worried about,” he said, in his slow and deliberate diction. “People have made arguments against the coherence of the concept of nothingness, but many of those arguments seem fallacious to me. Take the claim that absolute nothingness is impossible because we can’t picture it. Well, you can’t picture hyper-dimensional physics either! But proving that the Null World is a genuine possibility is not my problem. It’s the problem of Leibniz and Heidegger and Christian philosophers and all the boys who want to make hay out of the question Why is there a world rather than nothing at all? If nothingness is impossible, then, as the medievals used to say, cadit quaestio—‘the question falls’—and I’ll just go have a beer!”
But, I asked, isn’t nothingness the simplest form reality could take? And wouldn’t that make it the most expected way for reality to have turned out—unless, that is, there were some sort of cause or principle to fill the void with a world full of existing things?
“Oh, I’ll grant that nothingness may be the simplest conceptually. But even if it is, why should this simplicity—this presumed simplicity—mandate the realization of the Null World in the absence of an overriding cause? What makes simplicity into an ontological imperative?”
It has become a “veritable mantra,” Grünbaum complained, that the simplicity of nothingness makes it objectively more probable.
“Certain scientists and philosophers gawk at the world and say, ‘We just know that simpler theories are more likely to be true.’ But that’s just their psychological baggage, their heuristic mode. It has nothing at all to do with the objective world. Look at chemistry. In ancient times, Thales held that all chemistry was based on a single element, water. When it comes to simplicity, Thales’s theory wins hand over fist against Mendeleyev’s nineteenth-century ‘polychemistry,’ which posits a whole periodic table of elements. But Mendeleyev’s theory is the one that matches reality.”
So I tried another tack. Simplicity apart, isn’t nothingness the most natural form reality could have taken?
Grünbaum scowled slightly. “We know what’s ‘natural’ only by looking at the empirical world,” he said. “It’s logically possible that a person might spontaneously metamorphose into an elephant, but we never observe such a thing. So we don’t feel the slightest temptation to ask why this logical possibility is not realized. The collapse of a skyscraper, on the other hand, is something that is observed to happen from time to time. And when it does, we want an explanation, because it takes place against an empirical record of skyscraper collapse not occurring. Indeed, these nonoccurrences are so common that we are warranted in taking them to be ‘natural.’ When it comes to the universe, however, we’ve never observed its nonexistence, let alone found evidence that its nonexistence would be ‘natural.’ So why should we be tempted to ask for an explanation of why it exists?”
Here I thought I had him.
“But we have observed its nonexistence,” I interjected. “The Big Bang theory