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I'm not a fan of Kuhn, largely because he can be read as saying that, indeed, scientific models that get "overthrown" in a paradigm shift are therefore "invalid". (In the extreme, this leads to complete relativism, the idea that there is no such thing as a "valid" model at all. Kuhn himself has waffled on this point: sometimes he says he didn't really mean to take that extreme view, but other times he says things that are really hard to make sense of in any other way.) That leads people to believe that, for example, Newtonian physics must be "invalid" because it was "overthrown" by relativity. But it's really hard to square that claim with the fact that Newtonian physics (along with many other supposedly "invalid" models) gets used every day to make accurate predictions.

I think the bad science described in the article is, at least in part, a reflection of our losing sight of that ultimate objective: we build scientific models of the world in order to make accurate predictions. It's not enough to say, well, I used all the right statistical techniques, I used all the right double-blind control procedures, my results have been replicated. Those things are all necessary, but they're not sufficient; they're not the goal, they're only the starting point. The goal is to make accurate predictions. I think we get a lot of bad science because we don't enforce that requirement enough.




I was under the impression that models are thrown out in a paradigm shift because they aren't robust enough to account for edge cases that start out as weird (and ignored) outliers to the original model. These outliers eventually become glaringly apparent to the mainstream. Ideally, the new model resulting from a paradigm shift supercedes the old model while modeling the edge cases that the older model was unable to account for. Don't take my word for it, though. It's been a long time since I've read the book ;-).


I was under the impression that models are thrown out in a paradigm shift

But they aren't always thrown out in a paradigm shift; that's the point. Newtonian physics was not thrown out in the paradigm shift to relativity. Our understanding of why Newtonian physics works as well as it does within its domain of validity changed; but the fact that it does work within its domain of validity did not change.

Kuhn picks a number of examples where that was not the case--where the old model did get thrown out (for example, the paradigm shift from Aristotelian physics to Galilean/Newtonian physics, and the paradigm shift from the Ptolemaic to the Copernican model of the Solar System). But he tried to apply particular features of those examples to all paradigm shifts, which doesn't work.

Ideally, the new model resulting from a paradigm shift supercedes the old model while modeling the edge cases that the older model was unable to account for.

In the case of relativity, it did account for edge cases that Newtonian physics couldn't; but it didn't supersede Newtonian physics, as I noted above. We still use Newtonian physics where its predictions are accurate enough for our purposes, which is most of the time. It's only in particular domains (such as GPS, to pick an example ordinary people are familiar with) that we need relativity to get accurate enough results.




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