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Models.Behaving.Badly: Difference between revisions
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This is a narrow example of a broader principle which (counterintuitively) is true of all scientific theories: they only work within pre-defined conditions in carefully controlled experimental environments. Even Newton's basic laws of mechanics only hold true where there is zero friction, zero gravity, infinite elasticity, infinite regularity and a total vacuum, conditions that in real life never prevail. “Real life” experiments are thus indulged with a margin of error: that a heartily-struck cricket ball does not prescribe precisely the trajectory Newton says it ought is not evidence that his fundamental laws are wrong, but the simply that the pure experimental requirements for its true operation are not present. | This is a narrow example of a broader principle which (counterintuitively) is true of all scientific theories: they only work within pre-defined conditions in carefully controlled experimental environments. Even Newton's basic laws of mechanics only hold true where there is zero friction, zero gravity, infinite elasticity, infinite regularity and a total vacuum, conditions that in real life never prevail. “Real life” experiments are thus indulged with a margin of error: that a heartily-struck cricket ball does not prescribe precisely the trajectory Newton says it ought is not evidence that his fundamental laws are wrong, but the simply that the pure experimental requirements for its true operation are not present. | ||
All scientific - and, for that matter, any other linguistic - theories benefit from this “get out of jail” card: they are what philosopher {{author|Nancy Cartwright}}calls “[[nomological machine]]s”, explicitly pre-defined to be “true” only in tightly circumscribed (and often practically impossible) conditions. The looseness or tightness of those constraining conditions and the consequences of marginal variations to them determine how useful the theory, or metaphor, is in practice. ''F=MA'' will be a better guide for a flying cricket ball than for the [[ | All scientific - and, for that matter, any other linguistic - theories benefit from this “get out of jail” card: they are what philosopher {{author|Nancy Cartwright}}calls “[[nomological machine]]s”, explicitly pre-defined to be “true” only in tightly circumscribed (and often practically impossible) conditions. The looseness or tightness of those constraining conditions and the consequences of marginal variations to them determine how useful the theory, or metaphor, is in practice. ''F=MA'' will be a better guide for a flying cricket ball than for the proverbial [[crisp packet blowing across St. Mark’s Square]]. | ||
{{author|Emanuel Derman}} thinks science really speaks truths, while models peddle something less worthwhile. He sees a qualitative difference and not merely one of degree. Models he treats as broadly analogous with metaphors, which he says depend for their validity on comparison with an unrelated scenario. Theorems and laws, on the other hand, need empirical validation but once they have it stand rooted to the ground of reality by their own two feet. | {{author|Emanuel Derman}} thinks science really speaks truths, while models peddle something less worthwhile. He sees a qualitative difference and not merely one of degree. Models he treats as broadly analogous with metaphors, which he says depend for their validity on comparison with an unrelated scenario. Theorems and laws, on the other hand, need empirical validation but once they have it stand rooted to the ground of reality by their own two feet. | ||