
Originally Posted by
Nereid
Before this thread wanders off to become yet another interminable debate about philosophy and science, I hereby declare that I am going to try to drag it back to the general topic that I am interested in.
. . .
Do none of you reading this have anything on this that you want to share?
It seems to me to be pretty darn important!
Take neutrinos and the law of conservation of energy and the period 1930s to 1957. I'm sure you all agree (don't you? if not, say so!) that the relevant beta decays most certainly showed, in any number of repeated experiments, that energy was not being conserved (nor was momentum), and nothing has changed since - if you do the experiments today, in your own labs, energy appears to be not conserved (nor does momentum). Yet few, if any, working physicists seriously regarded the law of conservation of energy as not universally true/applicable/valid/{insert your own word here}.
But why?
The way naive falsification is
supposed to work is the logically valid argument form also known as "modus tollens". If it's the case that hypothesis
H theoretically entails that a certain predicted observation
O will be observed in a particular experiment, then if
O is
not observed, that is supposed to logically entail that
H must be false.
H --->O
~O
----------
:. ~H
Thus falsification was thought to be privileged over mere confirmation because getting the observation that the theory predicts does not entail that the hypothesis must be true, because other, alternative hypotheses could have predicted the same observation. To reason thusly:
H --->O
O
-------
:. H
is technically to commit a logical fallacy: the fallacy of affirming the antecedent.
The only problem is that in the real world, more than just a particular hypothesis is being tested. There are also other auxiliary assumptions
Ai in play. So what is really falsified by not getting the predicted observation is the conjunction of the hypothesis and the auxiliary assumptions (
H ^ Ai).
So to return to the first example, the schematic of the argument really should be:
(H ^ A1) ---> O
~O
-----------
:. ~(H ^ A1)
:. ~H v ~A1
Of course if one knows ahead of time that
A1 is true, then one might possibly be assured that
H is therefore false:
~H v ~A1
A1
----------
:. ~H
Only problem with
that is there could still be yet other auxiliary assumptions that are not being taken into account.
So to return to your concrete example,
Nereid, the beta decay experiments seemingly violated the conservation of energy principle. So you're tempted to say that conservation of energy was falsified. But obviously, with 20-20 hindsight, we know that at least one other auxiliary assumption was in play: namely that the list of exotic particles was complete. So what was really falsified by the beta decay experiments was the dual conjunction of {(conservation of energy) AND (list of exotic particles is complete)}. And since the principle of conservation of energy is one of those basic ideas that rank right up there with logic and math themselves and is therefore not to be given up lightly, then the correct thing to do was to reject the auxiliary assumption that the list of exotic particles was complete, and thus posit the existence of a new particle, the neutrino.
And so to answer your other question, the principle of conservation of energy was never falsified, and even if to this day neutrinos had not been detected, the correct stance would be to continue to believe that there exist neutrinos while maintaining the truth of conservation of energy.
The above description is also known as the Quine-Duhem thesis (both philosophers BTW--ignore them at your own peril!)