Nov 6, JDN 2457699

I’ve been hearing some disturbing sentiments from some surprising places lately, things like “Economics is not a science, it’s just an extension of politics” and “There’s no such thing as a true model”. I’ve now met multiple economists who speak this way, who seem to be some sort of “subjectivists” or “anti-realists” (those links are to explanations of moral subjectivism and anti-realism, which are also mistaken, but in a much less obvious way, and are far more common views to express). It is possible to read most of the individual statements in a non-subjectivist way, but in the context of all of them together, it really gives me the general impression that many of these economists… don’t believe in economics. (Nor do they even believe in believing it, or they’d put up a better show.)

I think what has happened is that in the wake of the Second Depression, economists have had a sort of “crisis of faith”. The models we thought were right were wrong, so we may as well give up; there’s no such thing as a true model. The science of economics failed, so maybe economics was never a science at all.

Never really thought I’d be in this position, but in such circumstances actually feel strongly inclined to defend neoclassical economics. Neoclassical economics is wrong; but subjectivism is not even wrong.

If a model is wrong, you can fix it. You can make it right, or at least less wrong. But if you give up on modeling altogether, your theory avoids being disproven only by making itself totally detached from reality. I can’t prove you wrong, but only because you’ve given up on the whole idea of being right or wrong.

As Isaac Asimov wrote, “when people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together.”

What we might call “folk economics”, what most people seem to believe about economics, is like thinking the Earth is flat—it’s fundamentally wrong, but not so obviously inaccurate on an individual scale that it can’t be a useful approximation for your daily life. Neoclassical economics is like thinking the Earth is spherical—it’s almost right, but still wrong in some subtle but important ways. Thinking that economics isn’t a science is wronger than both of them put together.

The sense in which “there’s no such thing as a true model” is true is a trivial one: There’s no such thing as a perfect model, because by the time you included everything you’d just get back the world itself. But there are better and worse models, and some of our very best models (quantum mechanics, Darwinian evolution) are really good enough that I think it’s quite perverse not to call them simply true. Economics doesn’t have such models yet for more than a handful of phenomena—but we’re working on it (at least, I thought that’s what we were doing!).

Indeed, a key point I like to make about realism—in science, morality, or whatever—is that if you think something can be wrong, you must be a realist. In order for an idea to be wrong, there must be some objective reality to compare it to that it can fail to match. If everything is just subjective beliefs and sociopolitical pressures, there is no such thing as “wrong”, only “unpopular”. I’ve heard many people say things like “Well, that’s just your opinion; you could be wrong.” No, if it’s just my opinion, then I cannot possibly be wrong. So choose a lane! Either you think I’m wrong, or you think it’s just my opinion—but you can’t have it both ways.

Now, it’s clearly true in the real world that there is a lot of very bad and unscientific economics going on. The worst is surely the stuff that comes out of right-wing think-tanks that are paid almost explicitly to come up with particular results that are convenient for their right-wing funders. (As Krugman puts it, “there are liberal professional economists, conservative professional economists, and professional conservative economists.”) But there’s also a lot of really unscientific economics done without such direct and obvious financial incentives. Economists get blinded by their own ideology, they choose what topics to work on based on what will garner the most prestige, they use fundamentally defective statistical techniques because journals won’t publish them if they don’t.

But of course, the same is true of many other fields, particularly in social science. Sociologists also get blinded by their pet theories; psychologists also abuse statistics because the journals make them do it; political scientists are influenced by their funding sources; anthropologists also choose what to work on based on what’s prestigious in the field.

Moreover, natural sciences do this too. String theorists are (almost by definition) blinded by their favorite theory. Biochemists are manipulated by the financial pressures of the pharmaceutical industry. Neuroscientists publish all sorts of statistically nonsensical research. I’d be very surprised if even geologists were immune to the social norms of academia telling them to work on the most prestigious problems. If this is enough reason to abandon a field as a science, it is a reason to abandon science, full stop. That is what you are arguing for here.

And really, this should be fairly obvious, actually. Are workers and factories and televisions actual things that are actually here? Obviously they are. Therefore you can be right or wrong about how they interact. There is an obvious objective reality here that one can have more or less accurate beliefs about.

For socially-constructed phenomena like money, markets, and prices, this isn’t as obvious; if everyone stopped believing in the US Dollar, like Tinkerbell the US Dollar would cease to exist. But there does remain some objective reality (or if you like, intersubjective reality) here: I can be right or wrong about the price of a dishwasher or the exchange rate from dollars to pounds.

So, in order to abandon the possibility of scientifically accurate economics, you have to say that even though there is this obvious physical reality of workers and factories and televisions, we can’t actually study that scientifically, even when it sure looks like we’re studying it scientifically by performing careful observations, rigorous statistics, and even randomized controlled experiments. Even when I perform my detailed Bayesian analysis of my randomized controlled experiment, nope, that’s not science. It doesn’t count, for some reason.

The only at all principled way I can see you could justify such a thing is to say that once you start studying other humans you lose all possibility of scientific objectivity—but notice that by making such a claim you haven’t just thrown out psychology and economics, you’ve also thrown out anthropology and neuroscience. The statements “DNA evidence shows that all modern human beings descend from a common migration out of Africa” and “Human nerve conduction speed is approximately 300 meters per second” aren’t scientific? Then what in the world are they?

Or is it specifically behavioral sciences that bother you? Now perhaps you can leave out biological anthropology and basic neuroscience; there’s some cultural anthropology and behavioral neuroscience you have to still include, but maybe that’s a bullet you’re willing to bite. There is perhaps something intuitively appealing here: Since science is a human behavior, you can’t use science to study human behavior without an unresolvable infinite regress.

But there are still two very big problems with this idea.

First, you’ve got to explain how there can be this obvious objective reality of human behavior that is nonetheless somehow forever beyond our understanding. Even though people actually do things, and we can study those things using the usual tools of science, somehow we’re not really doing science, and we can never actually learn anything about how human beings behave.

Second, you’ve got to explain why we’ve done as well as we have. For some reason, people seem to have this impression that psychology and especially economics have been dismal failures, they’ve brought us nothing but nonsense and misery.

But where exactly do you think we got the lowest poverty rate in the history of the world? That just happened by magic, or by accident while we were doing other things? No, economists did that, on purpose—the UN Millennium Goals were designed, implemented, and evaluated by economists. Against staunch opposition from both ends of the political spectrum, we have managed to bring free trade to the world, and with it, some measure of prosperity.

The only other science I can think of that has been more successful at its core mission is biology; as XCKD pointed out, the biologists killed a Horseman of the Apocalypse while the physicists were busy making a new one. Congratulations on beating Pestilence, biologists; we economists think we finally have Famine on the ropes now. Hey political scientists, how is War going? Oh, not bad, actually? War deaths per capita are near their lowest levels in history? But clearly it would be foolhardy to think that economics and political science are actually sciences!

I can at least see why people might think psychology is a failure, because rates of diagnosis of mental illness keep rising higher and higher; but the key word there is diagnosis. People were already suffering from anxiety and depression across the globe; it’s just that nobody was giving them therapy or medication for it. Some people argue that all we’ve done is pathologize normal human experience—but this wildly underestimates the severity of many mental disorders. Wanting to end your own life for reasons you yourself cannot understand is not normal human experience being pathologized. (And the fact that 40,000 Americans commit suicide every year may make it common, but it does not make it normal. Is trying to keep people from dying of influenza “pathologizing normal human experience”? Well, suicide kills almost as many.) It’s possible there is some overdiagnosis; but there is also an awful lot of real mental illness that previously went untreated—and yes, meta-analysis shows that treatment can and does work.

Of course, we’ve made a lot of mistakes. We will continue to make mistakes. Many of our existing models are seriously flawed in very important ways, and many economists continue to use those models incautiously, blind to their defects. The Second Depression was largely the fault of economists, because it was economists who told everyone that markets are efficient, banks will regulate themselves, leave it alone, don’t worry about it.

But we can do better. We will do better. And we can only do that because economics is a science, it does reflect reality, and therefore we make ourselves less wrong.