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Originally Posted by Ari Jokimaki
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Originally Posted by korjik
To say that "Newton's law of gravitation has been falsified." Not very useful at all.
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In principle I agree with that, but it wasn't the original setting that there was centuries old theory which pretty much everyone knows has been falsified ages ago. It was about current theory that is generally considered as not yet falsified. |
This is an interesting, and I suspect, common, perspective; namely, that:
a) if something has been 'around' (in textbooks, etc) for a long time ("centuries"), that somehow makes it more immune to falsification;
b) if the something is, or could be, called a "theory"*, it gets to hang on longer in the face of (good, independently verified) observations that falsify it
c) 'falsification' cannot be applied retroactively, it can only be used for things within the last generation or so (~30 years).
In the context of "collisionless CDM",
korjik's and
lomiller1's remarks align quite nicely with yours
Ari Jokimaki: "collisionless CDM" is neither vegetable nor mineral (there are, no doubt, whole classes of potentially falsifiable hypotheses that could be called "collisionless CDM", and the only 'theory' that comes even close isn't even called such ... LCDM cosmological models contain 'non-baryonic CDM', but its properties are extremely poorly constrained at the galaxy and kpc level, and below).
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To say that "Y is falsified by set of observations X" in my opinion is very useful when Y is generally considered as not yet falsified. However, Nereid's attitude in this matter seems to be something like we should only talk about observation set X as a problem for Y if we already know how to fix Y so that X is not a problem for it anymore. That's somewhat similar to the situation where I would take my bicycle to repair shop but I wouldn't be allowed to tell them what's the problem if I myself wouldn't know how to fix it.
I'm not much of a fan of this current trend of going from "truth" to "truth", i.e. we consider one theory to be "truth" and we only abandon that theory if we have another theory which we can start considering as "truth". I would be quite happy to be officially in "we don't know" state, and just look for more observations to quide us, and perhaps do some low level hypothesizing.
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It seems that what I wrote is somewhat ambiguous, let me try again.
Let's replace 'falsify' with 'rule out', and add some riders concerning quantitative measures of how inconsistent a hypothesis is with (good, independently verified) observations. In this case {observations X} can rule out {hypothesis Y}, at the n sigma level (or something similar).
All well and good.
But what do you do on Monday, when you go to the lab? Y is dead, how do you go about formulating another falsifiable hypothesis? After all, it doesn't make much sense to ask for a million seconds of HST time if you have no idea where you're going to point it, what instruments you're going to use, and so on (let alone how you will use the data from those million seconds of observing to test something).
Back to beta decay: what status should we give the 'law' of conservation of energy, between the first discovery of 'missing energy' in such decays and 1957?
Or, more up to date, between Davis' first solar neutrino results and the discovery of neutrino oscillations, what (if anything) could have been said to have been falsified (by Davis' results)? solar models? the whole of the Standard Model of particle physics? And after neutrino oscillations were discovered, did one or other theory/model/etc become 'unfalsified'?
After all, 'falsification' isn't a terribly useful concept if its scope of applicability is highly ambiguous (or, worse, arbitrary or undefinable), don't you think?
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or, even better in the case of Newtonian gravity, a "law"!