By "physically sensible," what do you mean? When I say that, I usually mean something that my brain is good at modeling,
It's hard to put my finger on this exactly. To me, physically sensible just means it sounds reasonable under the context of observations and everything else that we know. In this specific case, the idea of infinitely many universe branches constantly forking off doesn't seem physically sensible to me when all we observe is a single universe.
In what sort of situation would you expect a correct theory to not be physically sensible?
This just happens all the time. For example, to get the free-fall time for a falling object, you have to take a quadratic root of an expression, which in principle gives a "negative time" root/solution. This solution is obviously nonsense, so you just discard it and don't pay attention to it, but you don't conclude that the theory is wrong.
This just happens all the time. For example, to get the free-fall time for a falling object, you have to take a quadratic root of an expression, which in principle gives a "negative time" root/solution. This solution is obviously nonsense, so you just discard it and don't pay attention to it, but you don't conclude that the theory is wrong.
If you don't discard it, and do pay attention to it, you discover it is sensible.
"Negative time" is time before the time you labelled as zero. The negative solution is the time at which the object would have been at the end point, moving upwards, to get to the starting point at time zero.
http://www.scottaaronson.com/blog/?p=1103
Eliezer's gung-ho attitude about the realism of the Many Worlds Interpretation always rubbed me the wrong way, especially in the podcast between both him and Scott (around 8:43 in http://bloggingheads.tv/videos/2220). I've seen a similar sentiment expressed before about the MWI sequences. And I say that still believing it to be the most seemingly correct of the available interpretations.
I feel Scott's post does an excellent job grounding it as a possibly correct, and in-principle falsifiable interpretation.