Anders Sandberg wrote:
> Brain-wave recognition of sentences
> P. Suppes, B. Han and Z. L. Lu
> Proc Natl Acad Sci U S A, 95:26 15861--6 Dec 22 1998
I wasn't expecting that for fifteen years.
> Is the Strong Anthropic Principle Too Weak?
> A.Feoli, S.Rampone
> to appear in Il Nuovo Cimento B
> Something for the discussions about the Great Filter, I suppose; I'm
> personally not that fond of this realm.
Actually, they just name ("Mediocrity Anthropic Principle") something that I and probably everyone else has been assuming: The Strong Anthropic Principle doesn't force a large chance of sentient life on any particular planet, just an awful lot of planets.
Not that I believe in the SAP - what I believe is that _given_ an abundance of A, improbabilities up to 1/A can be invoked to explain the existence of observers. Call it the Improbability Anthropic Principle. (This works in reverse; sufficient improbabilities suggest a large abundance generating them. Thus, even if our solar system was surrounded by a dust cloud, we might eventually deduce the existence of other systems from evolutionary biology.)
What's relevant to the Great Filter Paradox is whether the abundance is such that we'd expect lots of sentient races in our past light cone. I certainly get that impression. Self-replicating chemicals may be far more improbable without all the heavy elements, but is it really impossible enough that NO life at ALL would exist in early galaxies? And we can see (= in our light cone) galaxies so old and burnt-out that they have far higher densities of heavy elements*; why haven't the inhabitants come knocking?