Why Does the World Exist: An Existentia - By Jim Holt Page 0,58
was nothing, you’d still be complaining!’ ”
I told him the joke came from Sidney Morgenbesser, an American philosopher who had died a few years ago.
“Haven’t heard of him,” Deutsch said.
But how could Deutsch be so cavalier about the mystery of existence? After all, he didn’t believe that there was just one world. His view of reality encompassed a huge ensemble of worlds, all existing in parallel: a multiverse. The multiverse was for Deutsch what God had been for Swinburne: it was the simplest hypothesis that explained what we observed around us—notably, the weird phenomena of quantum mechanics. If the physical laws governing the multiverse mandated their own comprehensibility, as Deutsch believed, shouldn’t they also mandate the comprehensibility of reality as a whole?
“I don’t think that an ultimate explanation of reality is possible,” he said, shaking his head. “That doesn’t mean I think there’s a limit to what we can explain. We’ll never run into a brick wall which says, ‘NO EXPLANATION BEYOND THIS POINT.’ On the other hand, I don’t think we’ll find a brick wall that says, ‘THIS IS THE ULTIMATE EXPLANATION FOR EVERYTHING.’ In fact, those two brick walls would be almost the same. If, qua impossibile, you were to have an ultimate explanation, it would mean the philosophical problem of why that was the true explanation—why reality was this way and not another—would be forever insoluble. Hello, I hear the water boiling!”
He went into the kitchen. Lulie smiled at me and continued to pick at her macaroni.
When Deutsch emerged a few moments later with a teapot and a plate of biscuits, I asked him whether he was puzzled at all by the existence of the multiverse. Was the question Why is there something rather than nothing? a profound one, or was it simply misguided?
“Hmmm,” he responded, touching his temple, “… a deep question … a misguided question… . Look, I can’t rule out the possibility that there is a foundation for reality. But if there is, the problem of why that’s the foundation would still be insoluble.”
He took a sip of tea and continued, “Take the ‘first cause’ argument, the idea that the existence of the world must be explainable by some sort of originating event. It’s hopelessly parochial! The idea that things are always caused by things that come before them in time has nothing to do with logic or explanation as such. You could imagine an explanation where something was caused by things happening at all different times, past and future. Or an explanation that didn’t have anything to do with time at all, or even with causes. The real question you want to answer is not what came before, but why something is the way it is.”
I gingerly sipped at my cup of tea, which did not seem to be poisoned.
“You can’t give a once-and-for-all definition of what an explanation is,” Deutsch said. “In fact, important explanatory advances often change the meaning of explanation. My favorite example is the Newtonian-Galilean revolution, which not only brought in new laws of physics, but also altered the very notion of what a physical law is. Previously, laws had been rules stating what happens. Kepler’s laws, for instance, were about how the planets traveled around the sun in elliptical orbits. Newton’s laws were different. They didn’t talk about planets or ellipses. Instead, Newton’s laws were rules that any such system would obey. It’s a different style of explanation, one that hadn’t been thought of before, one that wouldn’t even have been considered an explanation before. The same kind of explanatory revolution happened a couple of hundred years later with Darwin. Previously, when people asked, ‘Why does this animal have the shape it does?’ they expected that the answer would cite some property of the shape—that it was efficient, that it was favored by God, and so forth. After Darwin, the answer wasn’t about properties of the shape, but about how that shape had come into existence by evolution. Again, it’s a different style of explanation.”
Deutsch paced back and forth as he spoke. I remained seated on the sofa next to Lulie, who had finished her plate of macaroni and cheese.
“This point about the fluid nature of explanation is a real hobby horse of mine,” he continued, his voice gaining in intensity. “I think we’re going to need a different style of explanation to solve problems like free will and consciousness. These are fundamentally philosophical problems, not technical problems. I don’t think artificial intelligence will be achieved until philosophical