Dear David Layzer,
Thanks for a lucid, entertaining, and informative essay. I have a few comments and a general question.
Much seems to hinge on the assumption of an infinite universe. While I have much trouble imagining an infinite universe, I have just as much trouble imagining a finite universe, and neither seems subject to physical confirmation. The other assumption (G & V) is that the observable universe is in a definite quantum state. David Berlinski has pointed out that "physicists have found it remarkably easy to pass from speculation *about* the wave function of the universe to the conviction that there *is* a wave function of the universe."
But, based on those assumptions, I am happy to see that you arrive at the conclusion that you do, with respect to multiple copies of ourselves.
Now the question. An issue that has assumed some importance in this contest is the nature of information. Some insist that information is a physical "thing", while others, myself included, believe that information is descriptive in nature, dependent upon a frame or context, and having meaning only in a specific interpretation.
In this regard, you mention the information in biological structures, which is surely valid because DNA coding is interpreted by the cell. But then you speak of information "stored in sunlight", and in terms of non-random distributions in the Sun's core.
Let us assume that there are two theories of stellar processes, and that the energy (and possibly polarization) of the sunlight can be used to distinguish between these two and determine the 'correct' theory. Why is energy not sufficient for this process of interpretation? Why must one speak of 'information stored in sunlight'? What is it that physically exists besides the energy?
My point is that there seems to be a great deal of confusion as to whether or not information is physically 'real', as your usage suggests, and there seems to be no need in this case to speak of 'information stored'.
I realize that such usage is somewhat appropriate for probability distributions and entropy, but either it is descriptive, depending upon the context of an interpretative theory, or it is physical, having a reality above and beyond context.
Would you care to address this point?
Thanks again for a well written essay whose conclusion I agree with.
Edwin Eugene Klingman