Multiverse Musings: Fine-tuning and B-theories of Time
I recently received an email with a few good questions.
Do the multiverse models espoused by Sean Carroll and Alan Guth require fine-tuning at the level of the multiverse “bubble machine?”
Briefly, yes. Here are some details.
The multiverse dramatically impacts how fine-tuning arguments work. When considering probability arguments, like the fine-tuning ones, you must account for two factors: the probability of the event in question and the sample size. For example, the chance of heads on any given coin toss is 50 percent. However, tossing a coin 100 times virtually assures that heads will arise. Although the probability of life may be extremely low, the multiverse purports to give an extremely large number of samples—an infinite number in most multiverse models. Unless the chance of life arising by strictly naturalistic mechanisms is exactly zero, life will arise in the multiverse.
This challenge modifies how we must think about the life question. In a single, finite universe not significantly larger than the observable universe, we must deal with the seemingly low probability of finding an environment meeting all the conditions life requires as well as with the similarly small probability of life arising in that environment. Assuming a non-zero probability for these two criteria, the multiverse provides a sufficiently large sample size such that the relevant question changes to, How typical is life on Earth considering all the life that will exist in the multiverse?
Besides the usual evolutionary story, two other mechanisms provide a naturalistic means to make life, namely thermal fluctuations and highly advanced computer simulations. The key point to remember regarding these two options is that they occur far more often than the evolutionary option (unless the multiverse generator is fine-tuned), meaning we are still atypical. However, if these two alternative scenarios explain our existence, we still see a highly atypical environment. Yet, atypicality implies fine-tuning or design.
As far as I can tell, this atypicality argument holds for any multiverse model that seeks to explain our existence through the usual evolutionary mechanism.
Also, what are the implications for the kalaam argument, free will, and the Christian faith as a whole in light of the fact that science seems to suggest a B-theory of time? Does science suggest that the past, present, and future are equally real and that our perception of time passing is an illusion due to our observation of entropy?
Good question, one lacking a full answer at this point. For reference, the main difference between an A-theory of time and a B-theory is that tense and order matter in an A-theory, whereas in a B-theory only order matters.
As I understand, historic Christianity holds that while humanity exists within time (thus, past, present, and future matter), God exists outside of time and sees and knows all things before they happen (see Revelation 22:13). It may be that humanity’s experience is more consistent with an A-theory while God’s view is more consistent with a B-theory (even if it muddies how we understand the coexistence of God’s sovereignty and man’s free agency).
Scientists don’t have a final answer on this question yet, but I don’t see any fundamental problems this raises for a Christian worldview that believers have not already been wrestling with for thousands of years. If you have additional thoughts on this issue, send me an email.