I confess that I have a recurring nightmare. In it, I realize that everything I’ve ever written about economics is wrong. Neoclassical economics is not, as I’ve repeatedly claimed, a pile of bullshit. In this nightmare, neoclassical economics is correct. And as a strident critic of neoclassical theory, I realize the horrible truth. I’m a crank!
I wake up in a cold sweat, wondering if I’m wasting my life. Then, as rational thought returns, my fears ebb away. I think about everything I know about neoclassical economics — its flaws, its absurdities. I reassure myself that I’ve made the right choice. I’m not a crank. I’m a rational critic of an absurd theory.
The crank identification problem
Now that I’ve told you about my nightmare, I’ll assure you that this post is not about my late-night fears. Instead, my nightmare got me thinking about an age-old problem in science. How do you tell if someone is a crank?
It would be nice if there was a simple algorithm that could identify a crank. I can see the click-bait now:
Take this survey to tell if your colleague is crank. Get an answer in 10 minutes!
If I saw this link, I’d be tempted to click it, even though I know the crank survey can’t possibly work. There is no universal algorithm for identifying a crank. The closest we have is the motto of the Royal Society: nullius in verba. It means ‘on the word of no one’.
Science is founded on the principle that there are no authorities. The only way to judge if someone is a crank is to think rationally for yourself. You must become knowledgeable in the subject matter. You must immerse yourself in the crank’s arguments, and in the counterarguments. You must study the evidence, and if needed, run your own tests. In short, to identify a ‘crank’ you must become a scientist yourself.
You likely see the problem with this approach. Few people have the time to become experts in one subject. And no one has the time to become an expert in every subject. So the best way to identify a crank (do science for yourself) is out of most people’s reach.
As a non-expert, what are you to do? How do you tell if your favourite internet commentator is a crank?
First, I’ll tell you what you shouldn’t do. Then I’ll give you a few tools (which are by no means foolproof) for distinguishing between cranks, on the one hand, and critics you should take seriously.
What you shouldn’t do to identify a crank
1. Don’t rely on credentials
Yes, credentials are the currency of academia. The academic hierarchy is based on little else. But credentials are a poor indicator of scientific truth. Most neoclassical economists, for instance, are impeccably credentialed. But their theory is still garbage.
The truth is that anyone can do good science, no matter their credentials. The corollary is that anyone can do bad science, no matter their credentials.
Yes, the importance of credentials is ingrained in us from grade-school on. But ideally, credentials should have no currency in science. So don’t judge a crank by their credentials (or lack thereof).
2. Don’t appeal to majority rules
It’s tempting to identify a crank by doing a headcount. Count the number of people who side with the ‘crank’. Then count the number of people who think the ‘crank’ is crazy. If the crank’s opponents outnumber the crank’s supporters, then you’ve found a crank!
Except you haven’t.
The truth is that all scientific theories are initially believed by only one person. It can’t be any other way. Scientific progress requires that new ideas beat out old ones. This means that new theories always start with few proponents. If the new theory is supported by evidence, the number of proponents should grow (if science works as intended).
So appealing to ‘majority rules’ is a bad way to identify a crank. It means that Galileo was a ‘crank’. During his life, the heliocentric view of the solar system was a minority position. Majority rules also means that Einstein was a crank. Before Einstein, no one thought that time and space were relative.
Sadly, majority rules (like the appeal to credentials) is alive and well in academia. It’s alive because the surest way to get citations is to adopt a popular idea and write about it prolifically. But just because everyone else is doing it doesn’t mean you should too. So don’t label someone a crank because they advocate a minority position. They may be a future Galileo or Einstein.
3. Don’t listen to ad homenem attacks
When you think someone’s a crank, it’s tempting to search the internet for a vitriolic attack on the person’s character. The internet, being what it is, will surely give you what you want.
The problem is that scientific truth has nothing to do with the character — good or bad — of the theorist. Some excellent scientists are assholes. Some terrible scientists are nice people.
Judging a theory by the character of the theorist is a very human thing to do. We are social animals that thrive on (maybe even require) gossip. Unfortunately, these social instincts aren’t helpful for doing science. Science is about the rational appeal to evidence. So forget about the vitriol you see on the internet. It won’t help you tell if someone’s a crank.
What you should do to spot a crank
Having admitted that there is no universal algorithm for identifying a crank, I’ll give you some methods that I find helpful. Obviously these methods aren’t foolproof. So be forewarned: break any of these rules sooner than conclude anything outright barbarous. 
1. Look for assumptions that are untestable
Science works by appealing to evidence. A scientific theory, in other words, must be vulnerable to being wrong.
Here’s an example. The laws of thermodynamics predict that all isolated systems will evolve towards an equilibrium. At equilibrium, any temperature differences that once existed will disappear. It’s clear that this prediction could be proved wrong. Just create an isolated system in the lab and show that it never reaches equilibrium. The fact that no experiment has every shown this puts the laws of thermodynamics on sound footing.
The flip side occurs when a theory is immune to evidence. Often this happens when core assumptions are untestable. Let’s use neoclassical economics as an example. Neoclassical theory assumes that humans are utility maximizers. This means that any human decision can, in principle, be chalked up to utility maximization — the quantitative pursuit of pleasure.
The problem is that utility is unobservable. We can observe a person’s actions. But we can’t see their mental calculus. So we can never know if a person has actually maximized their utility. Conversely, we can never know if they haven’t maximized their utility.
So if a suspected ‘crank’ calls bullshit on a theory by saying that its assumptions are untestable, you’d best listen. It doesn’t mean the ‘crank’ is correct. But it means, at the very least, that their critique deserves attention.
2. Look for assumptions that have been falsified
Another way to tell if a ‘crank’ is onto something is if they highlight evidence that contradicts a theory’s assumptions.
Let’s return to neoclassical economics. I just told you that one of its core assumptions — utility maximization — is untestable. But there are variants of this assumption that are testable. If people maximize utility, it’s plausible that they also maximize external payoffs.
The problem is that people don’t seem to do this. A classic experiment in behavioral economics showed that people don’t maximize external pay offs. In other words, when utility maximization is put in a testable form, it gets falsified.
What’s odd is that this experiment didn’t put a dent in neoclassical economics. In fact, if you go through the 20th century literature, you’ll find study after study that contradicts neoclassical theory. And yet the neoclassical juggernaut chugs on, unbothered by the real world. To neoclassical economists, this ‘evidence’ is inadmissible. It’s the work of cranks.
The lesson is that when a ‘crank’ tells you that a theory’s assumptions are violated by real-world evidence, you’d best listen.
3. Check if the discipline is insular
Good science is open. This means that it’s open to new ideas, new methods, and new people. What science shouldn’t be is insular. Insularity signals the death of science and the growth of theism (belief for its own sake).
Neoclassical economics, for instance, is an extremely insular discipline. Nicholas Loubere has found that about 70% of economists in the ‘top 10’ economics departments got their degrees from within these departments. Economists are also less likely to cite work from other disciplines. And they only value the research published in five select journals. This insularity is a sign that science isn’t working.
So if you want to identify a ‘crank’, see if the discipline they’re criticizing is insular. If it is, the ‘crank’ may be onto something.
4. Check if other fields criticize the discipline
The dream of science is the unification of knowledge. In this dream, different disciplines become different branches of the tree of knowledge. Each branch has its own insights, but they’re all connected by the unifying trunk. Biologist E.O. Wilson calls this ‘consilience’.
A sure sign that the dream of consilience hasn’t been realized is when different disciplines disagree with one another. You see this all the time in the social sciences. I once spoke with a sociologist who said that half of sociology consists of disagreeing with economics. (This made me laugh outloud.)
It’s not just sociologists who think economics is bullshit. I’d guess that a majority of anthropologists do too. And a growing number of biologists (like David Sloane Wilson) are adding their voices to the criticism. Neoclassical economics has many critics from many different disciplines. Its defenders, in contrast, come mostly from within the discipline.
So if you think someone’s a crank, see if their critique is shared by more than one discipline. If it is, the ‘crank’ may be onto something.
5. Locate the discipline in the hierarchy of knowledge
If someone tells you that everything in physics is bullshit, they’re probably a crank. Why? It’s not that everything in physics is correct — it isn’t. Instead, the person is probably a crank because physics is our most secure knowledge. The foundations of physics aren’t unassailable. But they’re pretty secure.
This security has nothing to do with physicists themselves. They’re not better scientists than the rest of us. No, the foundations of physics are secure because physicists study the simplest systems.
Here’s an example of this simplicity. If you studied high-school physics, you probably learned the equations of motion on an inclined plane. Maybe you even tested these equations yourself. If you did, you surely found that they were correct.
These equations — derived from Newton’s laws — are secure because they describe an exquisitely simple system. It’s a system so simple that anyone can set it up and test the equations for themselves. Millions of people have verified the results, making the knowledge secure.
But as we move to more complex systems, theory becomes more difficult to test. And for that reason, knowledge becomes less secure. Chemistry is more complex than physics, and so less secure knowledge. Biology is more complex than chemistry, and so less secure still. And the social sciences? They study impossibly complex systems. So knowledge in the social sciences is orders of magnitude less secure than in the natural sciences.
There’s a cruel tyranny that operates here. The more complex the system, the more data you need to test your theory. The tyranny is that the more complex the system, the harder it is to get data! Physicists who study simple systems can generate reams of data. But social psychologists who study complex human behavior struggle to get 100 data points.
So what does this hierarchy of knowledge tell us about cranks? Well, if someone tells you that everything in physics is wrong, they’re almost certainly a crank. The foundations of physics are just too secure to make this probable. But if someone tells you that everything in a social-science discipline (say economics) is wrong, they could be right. Social science is based on pretty flimsy foundations. So it’s a good bet that much of it is wrong.
The demarcation problem
Philosophers of science have thought for a long time about the ‘crank identification problem’. But they don’t call it this, of course. They call it the ‘demarcation problem’.
The demarcation problem is about how to distinguish between ‘science’ and ‘non-science’. It’s a problem that has kept many philosophers up at night. Karl Popper thought he had the solution with ‘falsifiability’. Scientific theories, Popper proposed, make falsifiable predictions. Pseudoscience, in contrast, does not.
Many scientists (including me) still think that falsifiability is the bare-bones standard of a good theory. But the truth is that falsification is never cut and dry. Take Newton’s theory of gravity. When an object’s orbit doesn’t agree with Newton’s theory, does this mean the theory is wrong? Maybe. Or maybe there’s just hidden mass that we can’t see.
This thinking isn’t just a historical curiosity. We currently live in the golden age of ‘dark matter’. The fact is that Newton’s theory of gravity fails spectacularly when applied to the motion of stars in galaxies. Stars rotate far faster than Newton’s theory predicts. In response to this failure, a majority of physicists have agreed that galaxies are awash in invisible ‘dark matter’.
But this isn’t the only possibility. Some scientists see dark matter as a fudge factor. It’s inserted, they say, everywhere that Newton’s theory fails. These fringe thinkers (like Mordehai Milgrom) propose that Newton’s theory needs to be modified at low acceleration. If you’re interested in this topic, I recommend reading Stacey McGaugh’s blog.  He writes eloquently about these issues. And although McGaugh writes about astronomy, the human dimension has parallels in all areas of science.
Back to the crank problem. The uncomfortable truth is that what is accepted as ‘fact’ in science often has more to do with popularity than with the objective appeal to evidence. Humans are social animals, and we’re all too susceptible to groupthink.
Yes, cranks abound — on the internet and in peer-reviewed literature. But sometimes the ‘cranks’ are right. When they are, we ignore them at our own peril.
Support this blog
Economics from the Top Down is where I share my ideas for how to create a better economics. If you liked this post, please consider becoming a patron. You’ll help me continue my research, and continue to share it with readers like you.
Sign up to get email updates from this blog.
 I’m paraphrasing George Orwell here. In Politics and the English Language, Orwell gave six rules for clear writing. The last rule was this: “Break any of these rules sooner than say anything outright barbarous.”
 Also check out Stacey McGaugh’s MOND Pages. They’re a treasure trove of information about dark matter and modified gravity. And while you’re at it, read this excellent paper by David Merritt called Cosmology and Convention.
[Cover image: Ryan McGuire]