Take the various theories of the doom which await us when global warming finally strikes. Like Sharknadoes. Or, better, take the theory of global warming itself; just that theory which says what will happen to the climate, and not the stuff in the climate (like us and sharks). Fifteen years ago this theory existed as a complex set of propositions. The specification of these is not of direct interest to us, but for ease call them GW1998, a theory. A prediction derived from this theory was that it was highly probable the world would have by 2013 burnt to a crisp, or whatever.
We did not roast, but GW1998 did not say we certainly would, therefore the theory is not falsified. Falsified, as we must ever remind ourselves, means to prove with 100% absolute certainty that something is false. The predictions, while awful, did not attain sufficient decrepitude to warrant falsification. Holders of GW1998 could continue to claim that it (the theory) might be true without running into logical difficulties. But you would hope, merely in the spirit of decorum, statements of support would now be couched with humility. That is, while GW1998 might still be true, the confidence of its creators should have been badly shaken. It wasn’t.
A month ago the IPCC, creators, or at least governors, of climate theories, announced that their confidence in global warming as a theory had increased and not decreased. To the world, this appeared as if somebody had discovered the keys to the liquor cabinet while the parents were away. But as clueless as the IPCC was, there were accusations from skeptics that GW1998 was falsified and should be abandoned. We now know the theory wasn’t falsified, but what civilians don’t realize is that it was abandoned.
Nobody uses GW1998 any more. It has been replaced by a succession of theories, most recently (let’s call it) GW2013. It is that theory which the IPCC cherishes, not GW1998. How they came to love it is their own business, but it was not and could not have been because they have verified skillful predictions made conditioned on the new theory (this is one way to ascertain the value of any empirical theory). There hasn’t been time to accumulate these predictions. They love it intrinsically, because of what it is and represents.
The switch to the new model was made behind the curtain, but it is rational to suspect that since most of the same people who created GW1998 also had a hand in GW2013, and that because GW1998 didn’t pan out so well, that GW2013 will be no great shakes. But that is neither here nor there for the principle of falsifiability. We can’t falsify a theory in advance unless we can show that its propositions necessarily lead to contradictions. This has not been done with GW2013.
How different GW1998 is from GW2013 is also not the business of falsifiability. But there is the sense, and there is some evidence in the form of the IPCC’s new document, that the differences are small and insubstantial. That is, the fundamental set of propositions that mankind is nefarious in his dealings with the atmosphere built into GW1998 remain current in GW2013. If this is so, then given the past performance of GW1998 it would seem “scientific” to keep quiet about GW2013 and discover something else to study with government funds until we reach some GW20XX where skillful predictions can be made. Don’t, as they say, hold your breath.
The trick that has been played is what accounts for both sides sputtering in wonderment that the other side “Just doesn’t get it.” Don’t get caught up in this. Learn instead to recognized when this is happening. Point out to your interlocutor that he is discussing theories and not a theory, and that the new theory is not yet proven.
Now, even if GW1998 were falsified—and it was not: it may have been proved of little value to civilians, and of great value to climatologists, but it was not falsified—I say, even if it were falsified, the trickster will claim that it was only a small part of the theory that was at fault, and that this was, or very soon will be, expunged. If this is so, the modified theory is a new theory; it is comprised of a different set of propositions. It must be judged anew.
The more complex the theory, the easier it is to make this maneuver; the easier it is to assume that if pieces (propositions) go missing or undergo surgery, the theory is still “the theory.” It usually happens when there is a beloved meta-theory beneath the formal theory. In this example, GW1998 is the formal theory and the meta-theory is that mankind is up to no good. But often the meta-theory is true, or likely true, as many examples in the intellectual history of physics will show.
It is the meta-theory that defenders of the formal theory often have in their minds when the speak of the formal theory, not recognizing the distinction, the formal theory almost a distraction, something to be gotten out of the way, like income tax forms.
It is hard labor to get people to focus on just what is and what isn’t being claimed and what observational evidence means to the formal or meta-theory, to tease apart the differences. And to get people to understand just why even poor theories are not often falsified.
Part III: The other examples.