Why Does the World Exist: An Existentia - By Jim Holt Page 0,44
simplicity such an epistemic virtue?
“There are innumerable examples to illustrate this,” he said, “and not just from science. A crime has been committed. A bank has been robbed. There are three clues. A chap called Jones was reported to be near the scene of the crime at the time of the robbery. Jones’s fingerprints were found on the safe. Money from a bank robbery was found in Jones’s garret. Plausible explanation: Jones did the crime. Why do we think that? Well, if the hypothesis that Jones did the crime was true, you would probably find such clues; and if it wasn’t, you probably wouldn’t. But there are an infinite number of other hypotheses that meet this dual condition—for example, the hypothesis that somebody dressed up like Jones as a joke and happened to walk near the bank; and another person, not in collusion with the first, had a grudge against Jones and put Jones’s fingerprints on the safe; and a third person, having no connection to the previous two, put the proceeds from a quite different robbery in Jones’s garret. That hypothesis also meets the dual condition for being true. But we wouldn’t think much of any lawyer who put it forward. Why? Because the first hypothesis is simpler. Science always reaches for the simplest hypothesis. If it didn’t, one could never move beyond the data. To abandon the principle of simplicity would be to abandon all reasoning about the external world.”
He looked at me gravely for a moment and then said, “Would you like some more tea?”
I nodded. He refilled my cup.
“Descriptions of reality can be arranged in order of their simplicity,” Swinburne continued. “On a priori grounds, a simple universe is more likely than a complicated one. And the simplest universe of all is the one that contains nothing—no objects, no properties, no relations. So, prior to the evidence, that is the hypothesis with the greatest probability: the hypothesis that says there is Nothing rather than Something.”
But simplicity, I said, did not force this hypothesis to be true. I refuted it by holding up a sugar biscuit.
“Right,” said Swinburne, “so the question is, what is the simplest universe that contains the sugar biscuit and the teapot and us and everything else we observe? And my claim is that the simplest hypothesis explaining it all is the one that posits God.”
The notion that there’s anything simple about the God hypothesis is one that drives a lot of atheist thinkers—Richard Dawkins, for example—up a wall. So I had to challenge Swinburne on that. First, though, a slightly less fraught subject: did it matter to his case for God whether the universe had a finite or an infinite past?
“I know that a lot of thinkers look at the Big Bang through metaphysical spectacles,” he said. “But I don’t think the issue of a cosmic beginning is deeply relevant. Nor did Aquinas. Aquinas thought that, as far as philosophy was concerned, the universe might well have been infinitely old. It was a matter of Christian revelation that it came into existence at a particular moment in time. That’s one way of reading Genesis. But suppose the universe has been going on forever, and that it’s always been governed by the same laws. It remains true that there is a universe, and there might not have been. Whether the laws that govern its evolution have been in operation for a finite or an infinite time, they’re still the same datum. And, for those laws to give rise to humans, they have to be of a very special sort. You might think that, given an infinite amount of time, matter will rearrange itself sufficiently to produce conscious beings. But that’s not so! Think of the balls careening around on a billiard table. Even in an infinite time, they will not assume all possible configurations. A cosmos must meet some very precise conditions in order for humans to appear.”
But what if our world is just one among a vast multitude of universes, each with different laws? Wouldn’t some of them be bound to produce beings like us?
“Yes, I know that the multiple-universe idea has captured a lot of headlines,” he said. “But that’s not relevant to my case either. Suppose each universe throws off daughter universes that differ from the mother universe in various ways. How can we know such daughter universes exist? Only by studying our own universe and extrapolating backwards and finding that, at some point, another universe must have split off from