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Old 01-03-2012, 01:32 PM
whc.03grady whc.03grady is offline
Join Date: Jul 1999
Location: Montana
Posts: 461
Originally Posted by Omphaloskeptic View Post
It is tempting to view logic and mathematics as basic, with physical laws somehow building on these. But physics is fundamentally an empirical science, not a logical one; if empirical physical results contradict logical derivations then it's the logic that's broken, not the physics.
I appreciate the fact that physics isn't built atop logic in the sense that you describe (though I have other, unexpressed feelings about this that aren't germane to the topic at hand), and I likely slid into that way of thinking in an earlier post. But it still seems to me that if we're dealing with something like a miracle here.
I'm thinking of Hume's treatment of miracles, which in short says (taking his example), which is more believable? That someone rose from the dead after three days, or that everyone's evidence supporting that occurrence is mistaken? Which does reason compel you to bet on?

The same kind of reasoning seems to apply here: if you had to bet, would you bet that (a) there are cases where contradictions obtain; or (b) the descriptions/interpretations of those cases are in error? Now, it's clear where I place my money, but I'm curious as to why others might bet differently?

Originally Posted by Omphaloskeptic View Post
You say that a cat must be either alive or not-alive (excluded middle), and implicitly count this as two distinct well-defined states exhausting all possibilities. At least one of these two properties is empirically shown to fail in quantum mechanics, however. The usual informal way in which physicists talk about this is to label two particular states of the cat system as "alive" and "dead" and then understand that quantum mechanics allows superpositions of these two states. Now you see that there's not actually a logical contradiction. There are more than two possibilities, so excluded middle does not apply, and "not-alive" is not the same as "dead".
I wonder if you could elucidate on this a bit. First, I don't see how changing "not-alive" to "dead" makes a difference with respect to there not actually being a logical contradiction. Second, I don't get how the physicist "understand[s] that quantum mechanics allows superpositions of these two states." (If I could get a handle on this (and if it's true, of course!), it might be resolved for me and render the rest of what I'm saying irrelevant.)

What's more, I don't see how empirical results can trump principles of logic or reasoning. The whole process of science is built upon certain more or less formal principles of reasoning: "If a theory is confirmed so-and-so many times, we can regard it as true" would be an example. I wholeheartedly agree with this principle, but hopefully we all can see that no experiment has ever, will ever, or could ever be performed to show that it's a good principle. The scientific process relies quite heavily on the principles of mathematics for instance, principles which themselves are in no way proven by science.

What I'm trying to say in this post is there are certain meta-scientific principles by which science operates that are not themselves provable within science, yet are accepted (NB: I do not take this to mean scientific reasoning is in any way deficient). But why is it that when some results seem to run contrary to a certain principle (non-contradiction), that the impulse in this case is to pitch the principle, not the results?

Last edited by whc.03grady; 01-03-2012 at 01:34 PM.