Dan said: > One thing that I have been writing about, perhaps with less clarity > than I would like, is the difference between something being > reducible to observations and being consistent with observations. > Another is whether one can define values like right and wrong or > good and evil in terms of phenomenon.
I think that in this post you aren't being as clear as you might have been. I would use "reducible" not in the sense of something being "reducible to observations" (whatever that might mean) but in terms of one theory or explanation being reducible to another. By this, I would mean that the predictions of the more fundamental theory can be used to produce the predictions of the less fundamental theory as a subset of its own predictions (at least in principle) or, which is almost the same thing, that the rules of the less fundamental theory can be derived from those of the more fundamental theory. Later, you somewhat conflate the relationships between: - two theories (your QED/chemistry example) - sets of states and a theory (the first part of your meteorology example) - an earlier state and a later state obeying the rules of a theory (the second part of your meteorology example) This conflation is most obvious in the paragraph on evolution and good and evil. Your prior argument about the weather comes down to there being no constraints on states in fluid mechanics that prevent the ( H & �S ) or ( �H & S ) states from being valid, but "good" and "evil" are more akin to theories than they are to states - they are, at least, interpretations of features of a history joining sets of states (or sets of such histories). Most especially, at the end of your message it would be better to talk about higher level theories being derivable from, inconsistent with or consistent with lower level theories. As an aside, you wrote: > Further, while the computational requirements for complex chemical > reactions are significant, the complications are more linear than > exponential. Isn't it the case that the complexity of solving the equations multi-particle quantum mechanics increases exponentially in the number of particles? In any case, these are merely quibbles: I'm grateful to you for writing these thought-provoking and generally carefully reasoned posts. Will there be an article in the series on causation? Rich _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
