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Re: Disparaging Popper

Brian "Philidor11" said:

To paraphrase (sorry if I'm mis-stating), if certainty is measured by
statistical confidence, 100% certainty is not possible. But if that's true,
then in fact no scientific theory can refute or preclude the accuracy of any
alternative theory. (I'm using the word theory in place of hypothesis on
purpose.) One theory may be only more likely than another based on arguable
criteria. That proposition is troublesome.

Well, not exactly. Yes, certainty in science is never 100% possible. In all sciences, the hypotheses, laws, and theories are generalizations based on probablistic outcomes. But, this doesn't mean that no scientific theory can refute or preclude the accuracy of any alternative theory, as you suggest.

Rather, we must remember that a scientific theory has five properties: it is 1) testable, 2) falsifiable, 3) gives results that are repeatable, 4) has predicitive power, and most importantly for scientific theories only (not hypotheses and laws), 5) it has explanatory power. If a new theory better EXPLAINS the portion of the universe we are investigating than an old theory, we do have a means of choosing one over the other, and it is not arbitrary. Newton's theory of gravity explained many things, but Einstein's theory of gravity explained all the things Newton's old theory had, plus some things it could not explain. Therefore, Einstein's theory of gravity, rooted in his larger theories about relativity and space-time, is selected because it has better explanatory power than Newton's.

Criteria I suppose are always "arguable," but the criteria (or better yet we should say data) are generally based on the amount of evidence from experiment, observation, etc., that would be explained by the theory. No scientific theory is ever perfect, though, and that's what keeps science as vigorous a discipline as it is.

Think of dinosaur extinction theories. They each have explanatory power to varying degrees. Some attempt to explain dinosaur demise through gradualistic mechanisms, whereas others explain dinosaur demise through catastrophic global enviornmental upheavals. I do not wish to get into the nitty-gritty of the various extinction hypotheses, but all can potentially be falsified. If, for example, your theory of dinosaur extinction involves disease, how does that explain the corresponding extinctions of non-dinosaur organisms? A more globally encompassing theory may better explain dinosaur AND other organismal extinctions, and so our disease theory may have to be modified or be rejected/falsified.

In any case, the power of a theory comes from its ability to explain, in our case, patterns in the evolutionary history of dinosaurs. Theories that explain and account for all or most of the evidence are generally selected for, whereas theories that are contradicted by the evidence or fail to explain certain evidence that newer theories do are either modified or eventually rejected/falsified.

Good question.

Matt Bonnan
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