It would be nice if the universe were finite, but you can't demand that a priori; it's enough that the infinite mathematical object obeys simple rules.
I'm saying that if we lived in another universe, and someone came along and described to us the wavefunction for the Schrodinger equation, and asked how we should regard the size of some part of the configuration space compared to some other part, the L^2 norm is the blindingly obvious mathematical answer because of the properties of the wavefunction. And so if we (outside the system) were looking for a "typical" instance of a configuration corresponding to a mind, we would weight the configurations by the L^2 norm of the wavefunction.
Because (as it turns out) the wavefunction has a distinguished exceptionally-low-entropy state corresponding to the Big Bang, the configurations where the wavefunction is relatively large encode in various ways the details of (practically unique) intermediate stages between the Big Bang state and the one under consideration: that is, they encode unique histories (1). So a "typical" instance of a configuration containing a mind turns out to be one that places it within a context of a unique and lawful history satisfying the Born probabilities, because the L^2 norm of the wavefunction over the set where they hold to within epsilon is much, much larger than the L^2 norm of the rest. So to the extent that I'm a typical instance of mind-configurations similar to me, I should expect to remember and see evidence of histories satisfying the Born probabilities.
...seriously, I don't see why people get worked up over this. OK, Eliezer has his infinite-set atheism, and you have your insistence on a naive theory of qualia, but what about everyone else?
(1) This is not a conjecture, it is not controversial, it is something you can prove mathematically about the Schrodinger equation in various contexts.
how we should regard the size of some part of the configuration space compared to some other part, the L^2 norm is the blindingly obvious mathematical answer because of the properties of the wavefunction.
Does "part of the configuration space" refer to a single state vector, or a whole region that a state vector might belong to? My impression is that measuring the latter sort of thing is problematic from a rigorous mathematical standpoint. Is this correct, and does it have consequences for your discussion?
These are extracts from some Facebook comments I made recently. I don't think they're actually understandable as is—they're definitely not formal and there isn't an actual underlying formalism I'm referring to, just commonly held intuitions. Or at least intuitions commonly held by me. Ahem. But anyway I figure it's worth a shot.
A proposal to
rationalizederive magick and miracles from updateless-like decision theoretic assumptions:(On Google+ I list my occupation as "Theoretical Thaumaturgist". ;P )