* I very much understand the problem to be solved. I am also partial to many-worlds, and was even before beginning From Eternity to Here (I am lifting from Wikipedia when I say it seems to me that wavefunction collapse absolutely must be “just an epiphenomenon of…quantum decoherence”), and in my reading on the subject I understand — though I don’t really have the tools to think about the problem myself — that deriving the Born probability is a problem for MWI. To be honest, I don’t fully grasp why it is not an equally bad problem for Copenhagen and other QM interpretations… but since MWI is the only interpretation that I’ve really been able to grasp in a way that makes sense to me (well, I have a soft spot for instrumentalism, if you can call that an “interpretation”) I guess it’s no surprise that I don’t understand how Born probabilities relate to other interpretations.

* I mostly followed the post itself, but not really in a deep meaningful way. I kinda followed the math, but there are some notations in there which I am very fuzzy on (I’ve never actually done any QM calculations myself, only seen them done), and I didn’t really quite see where the insight was.

* I didn’t follow the discussion in the comments at all. Way above my head.

So there’s some context on the degree of “aficionado” that I may or may not be. FWIW

I don’t at all disagree with this comment from Andy:

Speaking as one of the ‘aficionados’ who has read everything by Brian Greene and others (though not Lisa Randall – I’ll have to look for her) I don’t get tired of the GR and QM introductions. It is difficult enough to grasp that I always seem to gain a little better understanding of it by reading yet another perspective. I’ve read your book, and I think I was able to ‘grok’ about a third of the new stuff.

Indeed, as I mentioned in my “psuedo-review”, I actually very much appreciated the rehash of GR and QM, because although they are familiar concepts, I can’t exactly call it “old hack”.

Overall I think you did a wonderful job at this very difficult balancing act. The blog post was sort of just a random thought I had a little while after reading the explanation of how logarithms work. While having the math-y thinking skills to understand some of the points about entropy is a total separate skill from knowing what a logarithm is, or what scientific notation is, I imagine the subset of people who have the former but not the latter must be rather small.

Nevertheless, it is, as you point out, a very challenging task to balance audiences, and overall I think you did a great job. One thing I noticed — and this was after I wrote the psuedo-review in question, by the way — was that From Eternity to Here generally does an excellent job at drawing together enough context in a sufficiently organized manner that an astute reader is entirely prepared to make the next logical leap before you actually spring it on them. The particular example I am thinking of is your treatment of what you call the Boltzmann-Lucretius scenario. For literally pages before you finally dismantle it, I was practically shouting at the book: “But the most parsimonious cosmology in that case would be Last Thursdayism! And that’s no explanation at all!” This was not a thought that had ever occurred to me before, nor anything remotely like it, but the book does such a fine job at laying out the context in a logical way that I was already seeing some objections to such a scenario, something I most certainly could not have accomplished a few days ago.

That pedagogical approach — where the student is given the tools to see the answer at the instant before you give it to her, rather than having to wait to be told — is IMO the most satisfying, and probably the most effective.

I more or less stand by my blog post, but rest assured, I think this is a great book, and I realize the problem I am nitpicking about is a very challenging one for popular science writers — even more so when the problem being confronted is that nature of time. (I had to abandon Julian Barbour’s The End of Time partway through, because while I grokked many of the early sections, there came a point where I just wasn’t following it anymore… very difficult topic!)