I originally thought this was a decisive argument against Christianity and Islam. Then famed non-Christian told me a strong response for Christians and Muslims to give that I hadn’t thought of before. So now I just think it’s cool and has some pretty surprising implications!
Suppose that you wake up in a red room. There are two theories on offer:
You wake up in a red room every day for all of eternity. On each day, you have no memory of any previous days.
You wake up in a red room once, then in a green room every day for the rest of eternity. On each day, you have no memory of any previous days.
What should your credence be that the first theory is true? The answer is 100% or arbitrarily close to it. After all, given the first theory, 100% of wakeups are in red rooms. Given the second theory, 0% are. So your waking up *today *in a red room straightforwardly confirms the first theory over the second.
Here’s another way to see this: suppose that right after waking up, you couldn’t see the room color. Naturally, you ought to think conditional on theory 1, it’s guaranteed that you’re in a red room, while given theory 2, the probability is 0%. Thus, after finding that you are in a red room, you get an infinitely strong update in favor of theory 1.
The alternative view also implies that you should believe in reincarnation. Theories on which you live for a long time and have a more diverse assortment of experiences make it likelier that you’d have any particular experience. If I only live once, the probability that I’d ever have my present experience is very low—if I live countless lifetimes, then it’s much likelier.
Now, it’s true that if I live many times, the portion of my life that would be occupied by my present experience would be lower than if I only live this life once. But the view I’m objecting to explicitly regards the portion as irrelevant. It only cares about whether you have the experience at least once. And if you have many different experiences, it’s likelier that you’d have your present experience at least once.
If this principle, according to which 1 is infinitely likelier than 2 in the above case, is right, then on its face, it seems like bad news for Christianity and Islam. These religions standardly imply that we spend a short time in a situation like the one we’re currently in, before we get an infinite afterlife that’s totally different from our Earthly lives. This is relevantly like the theory where you wake up once in a red room then infinity times in a green room.
Now, exactly why this theory is defective will differ across theories. Given SSA, this is bad because it predicts a small portion of your life being in the red room. Given SIA, it’s bad because fewer total days are in the red room. And applying either one is very wonky in the infinite case—you might be an SIAer who has the SSAish view in the infinite case, because you think that you need to take a measure over actual observers, and this measure is determined by proportions. If there are infinite people, it’s a bit unclear what either view says. However, the arguments I gave also apply in the infinite case, and they indicate that you should favor theories on which a larger portion of your experiences are like the present one.
Here is the problem in a nutshell. When doing anthropic reasoning within a life, assuming you think the contents of your life can ever tell in favor of one hypothesis, you will either think:
Theories on which you have more total moments like the present one get an update.
Theories on which a larger portion of moments are like the present one get an update.
Theories on which there’s at least one moment like the present one get an update.
But on all three of these views, a hypothesis on which you live on Earth once and then spend forever in a different state is wildly defective compared to at least one other theory—and in each case, it’s defective relative to infinite reincarnation. Conditional on spending time on Earth, the probability that you’d have your exact experience at any time is low, so it does bad on theory 3. 0% of your life is occupied by experiences like the present one, so it’s bad on theory 2. You only get one Earthly life, so it’s bad on theory 1.
Are there any ways out for the Christian or Muslim? I think there’s a good reply, but I encourage you to think for yourself, because of the joys of discovery.
One very failed is to adopt compartmentalized conditionalization, according to which your evidence is just that your experiences were had somewhere. However, that view implies that you’re a Boltzmann brain and has other giant problems. It also probably doesn’t get you Christianity.
Here’s the right solution for the Christian or Muslim: they should adopt the portion view, according to which you favor theories where a larger portion of your life is occupied by experiences like the present one. However, they should deny that heaven is temporal in the ordinary sense. They should think that heaven is, in some sense, beyond time, or beyond metric time.
I don’t think this is a particularly weird modification. God is standardly thought to be timeless, yet to have supreme welfare. So then maybe we could have supreme welfare in some state that is importantly timeless or that is temporal but lacking in ordinary temporal succession. In addition, the beatific vision is the direct experience of God—but direct apprehension of a timeless God might be timeless.
If heaven doesn’t have metric time in the ordinary sense, then things won’t be analogous to the scenario where you are in a red room for finite time and then in a green room for infinite time. Instead, it’s like where you’re in a red room for a finite time and then in a green room in some state where time doesn’t work normally.
There are still questions to be asked of course. Does this non-metric time make sense? Does it make sense to be in a timeless state and have welfare? Can there be a progression from a state with ordinary time to one with modified heaven time? Does anthropic reasoning confirm infinite recurrence even after infinity people exist? But these don’t seem like decisive problems. Atheists are also pressured to think some funny things are going on with time, as on a lot of views, it either emerges from something non-temporal or is past eternal. All this stuff is weird. And if eternal recurrence is proved, then probably atheism is disproved.
I’m also inclined to reject views according to which your present existence favors infinite recurrence even once there are already infinite people. This is because adding recurrence doesn’t increase the cardinality of the number of people. The alternative view seems to lead to an unstable arms race where you should always favor theories that proliferate more centers. In my view, measuring things by portions and cardinality is probably the right way to go—but obviously this stuff is very confusing and weird, as all of infinite anthropics is.
So Christians, thank your lucky star that saved you from ARGUMENTATIVE DOOM. In commemoration, buy his best-selling book.
Time can bring you down, time can bend your knees
Time can break your heart, have you begging please
Begging please
Beyond the door, there's peace, I'm sure
And I know there'll be no more
Tears in heaven
—Eric Clapton and Will Jennings, “Tears in Heaven”
