Evolução,Controvérsia:É Cega e Somos Produtos do Acaso, ou, é Controlada por Algum Desígnio Desconhecido?

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Posted by: Eric | February 9, 2009 3:35 PM
http://scienceblogs.com/pharyngula/2009/02/singularly_silly_singularity.php#comment

PZ:

I also don’t believe in the gray goo nightmare scenario: we’re already surrounded by a cloud of miniscule replicating machines that want to break our bodies down into their constituent molecules. We seem to cope, usually.
Yes, we’ve coped with replicating machines that evolved in parallel with us. We haven’t ever had to cope with replicating machines that were intelligently designed. Evolution is stupid and blind and bad at searching design space for efficient designs. Humans are much better, and most likely would not have too much trouble coming up with a design our bodies can’t cope with.

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Posted by: Anton Mates | February 10, 2009 1:48 AM
http://scienceblogs.com/pharyngula/2009/02/singularly_silly_singularity.php#comment-1383528

Yes, we’ve coped with replicating machines that evolved in parallel with us. We haven’t ever had to cope with replicating machines that were intelligently designed. Evolution is stupid and blind and bad at searching design space for efficient designs. Humans are much better, and most likely would not have too much trouble coming up with a design our bodies can’t cope with.

But evolution is far more intelligent than humans when it comes up to finding robust designs. Human machines tend to be spectacularly good at accomplishing one goal in one environment, and lousy at coping in any other situation. Naturally-evolved machines come from lineages that have survived through, literally, every environment under the sun, and they have the versatility to show for it.

I would expect human-designed replicators to be really good at gooifying the first thousand-or-so humans they meet. Then they encounter a temperature band they don’t like, or a particular wavelength of sunlight which breaks them down, or humans with an allele for a certain protein which can jam their machinery, or bacteria which produce a certain enzyme that dissolves them, or a combination of their own waste products which becomes toxic at a certain concentration, and suddenly they’re facing constraints and limiting factors and countermeasures just like everything else in the universe.

Synthetic replicators may become permanent and ineradicable elements of our biosphere, but I find it hard to imagine them replacing it anytime soon.

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