Today's post, Reductionism was originally published on 16 March 2008. A summary (taken from the LW wiki):
We build models of the universe that have many different levels of description. But so far as anyone has been able to determine, the universe itself has only the single level of fundamental physics - reality doesn't explicitly compute protons, only quarks.
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I think the point was that modeling the brain with enough precision that nuclear physics became necessary to take into account would be intractable and likely not very useful anyway.
But you got the snark thing down, so upvotes for everyone.