After a brief spurt of debate over the claim that “97% of relevant published papers support anthropogenic climate change”, I think the picture has mostly settled to an agreement that – although we can contest the methodology of that particular study – there are multiple lines of evidence that the number is somewhere in the nineties.

So if any doubt at all is to remain about climate change, it has to come from the worry that sometimes entire scientific fields can get things near-unanimously wrong, especially for political or conformity-related reasons.

In fact, I’d go so far as to say that if we are not climatologists ourselves, our prior on climate change should be based upon how frequently entire scientific fields get things terribly wrong for political or conformity-related reasons.

Skeptics mock the claim that science was wrong before, but skeptics mock everything. A better plan might be to try to quantify the frequency of scientific failures so we can see how good (or bad) the chances are for any given field.

Before we investigate, we should define our reference class properly. I think a scientific mistake only counts as a reason for doubting climate change (or any other commonly-accepted scientific paradigm) if:

1. It was made sometime in the recent past. Aristotle was wrong about all sorts of things, and so were those doctors who thought everything had to do with black bile, but the scientific community back then was a lot less rigorous than our own. Let’s say it counts if it’s after 1900.

2. It was part of a really important theory, one of the fundamental paradigms of an entire field. I’m sure some tiny group of biologists have been wrong about how many chromosomes a shrew has, but that’s probably an easier mistake to wander into than all of climatology screwing up simultaneously.

3. It was a stubborn resistance to the truth, rather than just a failure to have come up with the correct theory immediately. People were geocentrists before they were heliocentrists, but this wasn’t because the field of astronomy became overly politicized and self-assured, it was because (aside from one ancient Greek guy nobody really read) heliocentrism wasn’t invented until the 1500s, and after that it took people a couple of generations to catch on. In the same way, Newton’s theory of gravity wasn’t quite as good as Einstein’s, but this would not shame physicists in the same way climate change being wrong would shame climatologists. Let’s say that in order to count, the correct theory has to be very well known (the correct theory is allowed to be “this phenomenon doesn’t exist at all and you are wasting your time”) and there is a large group of people mostly outside the mainstream scientific establishment pushing it (for approximately correct reasons) whom scientists just refuse to listen to.

4. We now know that the past scientific establishment was definitely, definitely wrong and everyone agrees about this and it is not seriously in doubt. This criterion isn’t to be fair to the climatologists, this is to be fair to me when I have to read the comments to this post and get a bunch of “Nutritionists have yet to sign on to my pet theory of diet, that proves some scientific fields are hopelessly corrupt!”

Do any such scientific failures exist?

If we want to play this game on Easy Mode, our first target will be Lysenkoism, the completely bonkers theory of agriculture and genetics adopted by the Soviet Union. A low-level agricultural biologist, Lysenko, came up with questionable ways of increasing agricultural output through something kind of like Lamarckian evolution. The Soviet government wanted to inspire people in the middle of a famine, didn’t really like real scientists because they seemed kind of bourgeois, and wanted to discredit genetics because heritability seemed contrary to the idea of New Soviet Man. So they promoted Lysenko enough times that everyone got the message that Lysenkoism was the road to getting good positions. All the careerists switched over to the new paradigm, and the holdouts who continued to believe in genetics were denounced as fascists. According to Wikipedia, “in 1948, genetics was officially declared “a bourgeois pseudoscience”; all geneticists were fired from their jobs (some were also arrested), and all genetic research was discontinued.”

About twenty years later the Soviets quietly came to their senses and covered up the whole thing.

I would argue that Stalinist Russia, where the government was very clearly intervening in science and killing the people it didn’t like, isn’t a fair test case for a theory today. But climate change opponents would probably respond that the liberal world order is unfairly promoting scientists who support climate change and persecuting those who oppose it. And Lysenkoism at least proves that is the sort of thing which can in theory sometimes happen. So let’s grumble a little but give it to them.

Now we turn the dial up to Hard Mode. Are there any cases of failure on a similar level within a scientific community in a country not actively being ruled by Stalin?

I can think of two: Freudian psychoanalysis and behaviorist psychology.

Freudian psychoanalysis needs no introduction. It dominated psychiatry – not at all a small field – from about 1930 to 1980. As far as anyone can tell, the entire gigantic edifice has no redeeming qualities. I mean, it correctly describes the existence of a subconscious, and it may have some insightful things to say on childhood trauma, but as far as a decent model of the brain or of psychological treatment goes, it was a giant mistake.

I got a little better idea just how big a mistake doing some research for the Anti-Reactionary FAQ. I wanted to see how homosexuals were viewed back in the 1950s and ran across two New York Times articles about them (1, 2). It’s really creepy to see them explaining how instead of holding on to folk beliefs about how homosexuals are normal people just like you or me, people need to start listening to the psychoanalytic experts, who know the real story behind why some people are homosexual. The interviews with the experts in the article are a little surreal.

Psychoanalysis wasn’t an honest mistake. The field already had a perfectly good alternative – denouncing the whole thing as bunk – and sensible non-psychoanalysts seemed to do exactly that. On the other hand, the more you got “educated” about psychiatry in psychoanalytic institutions, and the more you wanted to become a psychiatrist yourself, the more you got biased into think psychoanalysis was obviously correct and dismissing the doubters as science denalists or whatever it was they said back then.

So this seems like a genuine example of a scientific field failing.

Behaviorism in psychology was…well, this part will be controversial. A weak version is “psychologists should not study thoughts or emotions because these are unknowable by scientific methods; instead they should limit themselves to behaviors”. A strong version is “thoughts and emotions don’t exist; they are post hoc explanations invented by people to rationalize their behaviors”. People are going to tell me that real psychologists only believed the weak version, but having read more than a little 1950s psychology, I’m going to tell them they’re wrong. I think a lot of people believed the strong version and that in fact it was the dominant paradigm in the field.

And of course common people said this was stupid, of course we have thoughts and emotions, and the experts just said that kind of drivel was exactly what common people would think. Then came the cognitive revolution and people realized thoughts and emotions were actually kind of easy to study. And then we got MRI machines and are now a good chunk of the way to seeing them.

So this too I will count as a scientific failure.

But – and this seems important – I can’t think of any others.

Suppose there are about fifty scientific fields approximately as important as genetics or psychiatry or psychology. And suppose within the past century, each of them had room for about five paradigms as important as psychoanalysis or behaviorism or Lysenkoism.

That would mean there are about 250 possibilities for science failure, of which three were actually science failures – for a failure rate of 1.2%.

This doesn’t seem much more encouraging for the anti-global-warming cause than the 3% of papers that support them.

I think I’m being pretty fair here – after all, Lysenkoism was limited to one extremely-screwed-up country, and people are going to yell that behaviorism wasn’t as bad as I made it sound. And two of the three failures are in psychology, a social science much fuzzier than climatology where we can expect far more errors. A cynic might say if we include psychology we might as well go all the way and include economics, sociology, and anthropology, raising our error count to over nine thousand.

But if we want to be even fairer, we can admit that there are probably some science failures that haven’t been detected yet. I can think of three that I very strongly suspect are in that category, although I won’t tell you what they are so as to not distract from the meta-level debate. That brings us to 2.4%. Admit that maybe I’ve only caught half of the impending science failures out there, and we get to 3.6%. Still not much of an improvement for the anti-AGW crowd over having 3% of the literature.

Unless of course I am missing a whole load of well-known science failures which you will remind me about in the comments.

[Edit: Wow, people are really bad at following criteria 3 and 4, even going so far as to post the exact examples I said not to. Don’t let that be you.]