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Re: flights of fancy (or "I'm brave, but I'm chicken****")



In a message dated 95-12-06 13:41:12 EST, rowe@lepomis.psych.upenn.edu
(Mickey Rowe) writes:

>In the first place, your argument is weak in principle, much like the
>one of Greg's I criticized recently (the fact that George is also
>using similar arguments doesn't mean you should consider such
>arguments to be good chains of reasoning).  Just because evolution
>found a solution once doesn't mean it will find it multiple times (or
>even twice).  Jared Diamond had a wonderful piece on this in a column
>for _Natural History_ about five years back.  In talking about the
>probability of finding extra-terrestrial intelligence, he suggested it
>might not be that likely.  Just because *we* evolved it doesn't mean
>anything else has or will.  He analogized it to woodpecking in birds
>(which also appears to have evolved only once despite its obvious
>benefits to the lineage that evolved it).

Just because Mickey Rowe thinks an argument is weak doesn't mean the argument
is _wrong_. We're talking about a rather minor modification to the carpus
here, not an intricate set of interwoven adaptations as in woodpecking or the
evolution of intelligence. Neither Jared Diamond nor anyone else has any idea
whatsoever about the likelihood of finding extraterrestrial intelligence. And
no, I don't want to start an ETI thread here!

Which is more likely to evolve twice? Something that has already evolved
once, or something that has never evolved at all?