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Bold claims about time asymmetry
...given self-indication we should expect to be in a finite-probability universe with nearly the max possible number of observer-moment slots. Such universes seem large enough to have at least one inflation origin, which then implies at least one (and perhaps infinitely many) large regions of time-asymmetry like what we see around us. And if, as it seems, most observer-moments in such universes are in such regions, then we have explained why we see what we see.
That's from Robin Hanson, one of the least evil people I have met. I do not have the background to judge this claim but it makes sense to me. The question is whether you are willing to bite the bullet when you realize the other implications of what Robin is postulating, namely that you start dealing with expected values of infinity, most of all in ethics...
By the way, via Andrew Sullivan, here is new evidence for dark energy.
Posted by Tyler Cowen on August 13, 2008 at 11:20 AM in Science | Permalink
Comments
What does "least evil" feel like if we are not in one of those large regions of time-asymmetry? :)
Posted by: Yan Li at Aug 13, 2008 11:49:39 AM
The "dark energy" link does not provide evidence of dark energy. The study simply supplies evidence that expansion is accelerating.
Posted by: Darren at Aug 13, 2008 12:06:52 PM
Can someone explain what this means to ignoramuses like us?
Posted by: Unit at Aug 13, 2008 12:09:18 PM
Unit,
follow the link; it's pretty clear.
Posted by: josh at Aug 13, 2008 12:21:55 PM
It's been a while since I did any calculus, but can't you have different size infinities pretty easily? If you're comparing the limits of X and X-squared as X goes to infinity, X-squared will always be larger. Couldn't you handle various infinite utility equations using limits?
Posted by: Greg at Aug 13, 2008 12:42:13 PM
This is basically the weak anthropic principle, yes? Combined, of course, with some information about how initially low-entropy universes are especially hospitable to intelligent life.
Posted by: dWj at Aug 13, 2008 12:47:15 PM
I don't think it works, for reasons that I pointed out in a comment at OB (currently in moderation for excessive number of links). For background, see Boltzmann's Anthropic Brain or this Arrow of Time FAQ.
Posted by: Sean Carroll at Aug 13, 2008 12:51:41 PM
You seem peculiarly willing to make judgments about who is or is not evil.
Posted by: Doug at Aug 13, 2008 1:53:15 PM
...given self-indication we should expect to be in a finite-probability universe with nearly the max possible number of observer-moment slots. Such universes seem large enough to have at least one inflation origin, which then implies at least one (and perhaps infinitely many) large regions of time-asymmetry like what we see around us. And if, as it seems, most observer-moments in such universes are in such regions, then we have explained why we see what we see.
If we replaced the above by "God" do we lose any explanatory power?
Posted by: Bob Murphy at Aug 13, 2008 2:46:23 PM
"I think, therefore I am." But, I must say, "because I'm here" could be used to support a ton of suppositions, but it doesn't necessarily make it so.
So, we all know what the speed of light is. Anybody know why?
Posted by: Seth at Aug 13, 2008 4:59:27 PM
why don't we just use the surreal numbers for ethics? if real numbers aren't enough for electrical engineering we shouldn't assume they are enough for ethics.
Posted by: DK at Aug 13, 2008 6:00:36 PM
@Sean Carroll
Thanks very much for those links. I particularly liked your explanation for how time asymmetry suggests that there may not be any such thing as a general equilibrium. I wish more economists thought that way. I'm particularly intrigued by the suggestion that time could be a spontaneously broken symmetry. I'm guessing that gravity is the prime suspect for spontaneous time symmetry breaking. I saw that water boils up into a sphere that stays adjacent to a surface in (near) zero gravity conditions the other day. With perfectly smooth surfaces, it seems like it would have to be gravity that breaks that perfect sphere up into a million little bubbles right?
As an aside, it's interesting to note that there seems to be an analogous problem in economics right now. Endogenous growth theory has been stymied by the time symmetry of most microeconomic theories. Seems like the same prescription should apply -- maybe open systems like economies are never really in equilibrium.
Posted by: Michael F. Martin at Aug 14, 2008 12:02:53 AM
one of the least evil people I have met.
the infinite running gag.
Posted by: roissy at Aug 14, 2008 3:25:17 PM
