I've been reading Lee Smolin's Life of the Cosmos.

Great book and it makes a lot of sense that the conditions in black holes are the same as conditions at the big bang.

Question is, has his theory about Cosmological Natural Selection been disproved as the wikipedia article states?

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    $\begingroup$ My impression is that the idea is too vague to be provably right or wrong. I actually don't mean that as as harsh a criticism as it probably sounds. I think it's an intriguing idea, and it's not impossible a priori that it could be sharpened up to something more specific. But I don't think it has been formulated that precisely. $\endgroup$ – Ted Bunn May 19 '11 at 14:12
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    $\begingroup$ I think the guy wrote a shedload of papers on it - from reading the book I think it is quite precise (he's got a loads of references to actual papers in the book) and makes a number of quite narrow predictions (such as the one the wikipedia article mentions about size of pulsars). $\endgroup$ – JohnIdol May 19 '11 at 14:14

Yes, of course, it's trivial to disprove this idea because it's childish nonsense that may sell popular books for readers who don't understand the subject but that contributes nothing to to the actual science.

It's very easy to adjust the parameters of the cosmological and particle physics model we use to describe the Universe so that the number of black holes that are produced will be vastly higher than in our Universe - in which black holes are very rare. For example, move the inflation scale closer to the Planck scale to create higher non-uniformities in the CMB etc. That will also create a higher number of black holes. So our Universe is demonstrably not optimized for "black hole fertility". See also


In the first paper, Susskind also argues that Smolin needs to assume that the reproduction of universes through black holes beats eternal inflation which it almost certainly doesn't.

Moreover, the counting of black holes is really ill-defined because of the quantum nature of our world - in particular, tiny black holes are indistinguishable from ordinary heavy elementary particles. The very notion that the interior of a black hole may give rise to a new Universe contradicts the holographic principle (and related holographic bounds; you can't have excessively high entropy emerging out of a small region) and there are many other ways to see that the idea is both ill-defined as well as demonstrably wrong in all of its conceivable versions.

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    $\begingroup$ Thanks for the exhaustive answer ... and your unsolicited opinions ;) $\endgroup$ – JohnIdol May 19 '11 at 18:57

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