Sunday, July 22, 2012

Giving Up on Derek Parfit

(I post, therefore I am.)

I'm nearly through Jim Holt's wonderful Why Does the World Exist?: An Existential Detective Story. Holt is interviewed in today's nytimes. He asked, after talking with and citing so many scholars on the Big Question, why he did not include a biblliography. In response Holt gives a brief one. He says:

"For the physicist’s angle on cosmic existence, I would recommend Alex Vilenkin’s “Many Worlds in One.” For the scientifically informed theologian’s angle, try Richard Swinburne’s “Is There a God?” For a deliriously delightful romp through philosophical cosmology, read John Leslie’s “Infinite Minds.” Finally, please, please look up Derek Parfit’s essay “Why Anything? Why This?,” published in two parts in the London Review of Books (January 22 and February 5, 1998). If you’re like me, Parfit’s essay will make you weep tears of intellectual joy."

Sine I haven't wept for intellectual joy in at least a few days I pulled up the Parfit essays. Parfit is a well-known Oxford philosopher. I've run across his name many times before. He's now an emeritus professor, which means: he is old. But look at him. I'm getting old, and I want to look like Derek Parfit (born 1942) in 7 years!

OK. Here I go. I'm reading the two connected essays in the London Review of Books. And my thoughts as I move through them.

  • An infinite series of events cannot explain itself. We could still ask why this series of events occurred, rather than some other series of events, or no series of events at all. Steady State theorists like our unvierse as an infinite series of events. "They assumed that, if the Universe had no beginning, there would be nothing for a Creator to explain. But there would still be an eternal Universe to explain."
  • Suppose our universe in not eternal, since nothing preceded the big bang. The first event may have obeyed the laws of quantum mechanics. There may have been a random fluctuation in a vacuum. "But what physicists call a vacuum isn’t really nothing. We can ask why it exists, and has the potentialities it does. In Hawking’s phrase, ‘What breathes fire into the equations?’" (Sorry Lawrence Krauss. See here, and here.)
  • There could not be a causal explanation of why the universe exists. So also there cannot be a causal explanation of why God exists, since God (by definition) is a necessarily existent being. (Note: Parfit is an atheist.) But on why the unvierse exists, a lack of a causal explanation does not create a problem, since not all answers (explanations) are causal answers.
  • Parfit discusses the argument for God's existence based on anthropic coincidences. "Nor is it only life that requires this fine-tuning. If the Big Bang’s initial conditions had not been almost precisely as they were, the Universe would have either almost instantly recollapsed, or expanded so fast, and with particles so thinly spread, that not even stars or heavy elements could have formed. That is enough to make these conditions very special." This could be a mere coincidence, but that's improbable. It could be that a God is responsible for the fine-tuned universe. How does Parfit challenge this? (He does think it is worth challenging.)
  • Parfit thinks it is possible that the conditions needed for a fine-tuned universe were necessary. "If these life-allowing conditions were either very likely or certain to obtain, then – as the argument claims – it would be no coincidence that the Universe allows for complexity and life. But this fine-tuning might have been the work, not of some existing being, but of some impersonal force, or fundamental law." OK. Whatever caused the universe must be either chance, necessity, or design. Parfit thinks it was not chance. Nor does he think the universe was designed by God. That leaves necessity or, at least, strong probability. Parfit leaves this only as a possibility, and does not defend it. He then gives what he thinks is a stronger reason to reject both chance and the God hypothesis.
  • Parfit uses the rare earth argument, and makes an analogy to our universe. The needed physical conditions for there to be an earthlike planet may be rare. But, on the scope of the universe, the existence of such planets is not unreasonable or so improbable. OK. But there are many planets in the universe, but only one universe. Enter the multiverse.
  • "On this Many Worlds Hypothesis, there is no need for fine-tuning."
  • How does Parfit argue for the Many Worlds Hypothesis? He writes: "Some object that, since our world could not be causally affected by such other worlds, we can have no evidence for their existence, and can therefore have no reason to believe in them. But we do have such a reason, since their existence would explain an otherwise puzzling feature of our world: the appearance of fine-tuning." Parfit uses, it seems, inference to the best explanation. What's the best explanation for our obviously fine-tuned universe? His answer: the existence of multiple universes.
I think I'm going to stop reading the Parfit essays here. I think his commitment to atheism causes him to posit a multiverse. It can't be God who caused our fine-tuned universe. Of course, if you're an atheist.

Parfit writes:

"We... have the question why, in the Big Bang that produced our world, the initial conditions allowed for complexity and life. If there has been only one Big Bang, this fact is... hard to explain, since it is most unlikely that these conditions merely happened to be right.  If, instead, there have been many Big Bangs, this fact is easy to explain, since it is like the fact that, among countless planets, there are some whose conditions allow for life. Since belief in many Big Bangs leaves less that is unexplained, it is the better view."
I don't think so. We'll still need a multiverse generator, right?
I am not weeping tears of intellectual joy.