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Comment by mathieutd | Hacker News Reader

Economics professor here. I disagree. We formulate theories that we test using data. Same as physics except that economics is much more messy. Another difficulty is that in many cases (macroeconomics for instance) we cannot do experiments to test theories. This makes it much harder to learn from the data.

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I mentioned economics gets dogmatic. Occasionally, we even have economists who attempt to re-define science. Here's a quote from the article:

"Andrew Lo, an MIT economist, said that while physics has three laws that explain 99% of the phenomena, finance has 99 laws that explain only 3%. Not only do we not fully understand how the economy works but also there is an endless debate on how it should function."

You can have your own science threshold. But I think calling economics science is doing disservice to science. It distorts the public's perception of science.

Thats a silly way of looking at it. Every field of science has their own threshold for acceptance. Biology as a field is much less stringent than physics when it comes to p values for example. Psychology even less so. This ddoesnt mean physicists can go around saying Biology or Psychology are not sciences. Economics is a science - just not as well understood / clean as some other fields. Humans are a part of the equation which makes it harder.

I agree. 'Science' is either based on quantitative observation, or theory, or experiment that validates theory. Microeconomics largely follows this rubric, but I would say macroeconomics largely does not. Macro and international econ suffer from the same problems that psychology and sociology do as 'sciences' -- they're studies of very complex systems that are based on too little quantifiable theory that has been rigorously tested. As such it's a stretch to call any discipline that lacks a basis in natural law a science.

(IMHO, biology, which also deals in very complex systems, gets a scientific pass because so much of it is based on well tested chemistry and its methods are heavily experimental. (Aside from evolution, that is.) Likewise, cosmology benefits from its well-grounded bases in physics and geology.)

But that doesn't mean the study of such complex systems can't or don't employ scientific methods or standards that improve their utility greatly. For example, I'm a big fan of Piaget's work, though I would hesitate to call it science. Such work offers compelling insights, though with little real hope of us seeing farther by standing on the shoulders of giants.

Not only that, but economics seems to have suffered (and in many cases largely ignored) many of the methodological and foundational critiques of both its predecessor (as political economy) and its modern incarnation (capitalist economics). These criticisms come from both inside and outside the field, not to mention from a variety of hetorodox (periphery) sources, not limited to neo-Ricardians, Marxians, Post-Keynesians, Walrasian, and even Austrian School.

Every science has its object (that's what Plato thinks anyway) and thus different tools and methods are required for different objects. The tools in the science of philosophy are different to those of biology, which are still different to psychology. This is not a criticism of economics, philosophy, or science, since I don't consider science to be purely the methodology of the natural sciences. The multiplicity of seriously considered and valuable views within both philosophy and economics (there are more examples though) is unheard of in the natural sciences to my knowledge.

To say that economics is a science in the same sense as the natural sciences requires excluding heterodox schools since their methodology leads to different conclusions to orthodox economics. That is to say, we would need to declare one methodology as absolutely correct and all others as incorrect. From my limited knowledge reading around heterodox economics[0], I don't think such an exclusion is warranted.

[0] The likes of Sraffa, Veneziani and Yoshihara, Shaikh, Kliman, Mohun, etc.

I would rather say that most sciences differ from natural sciences. This is certainly true for any social science, but also for biology, medicine, certainly psychology and so on.

Similarly, heterodox schools are usually peripheral because they are peripheral to the current academic discourse. So for example Marxian primary material is a critique of past-tense economics. Post-Keynesians have a fetish for one particular concept or method (flows, MMT, crisis prediction) and reject everything outside of it. The Austrian School rejects the use of data and even formal modeling altogether, all while academic economics becomes more experiment based.

Nevertheless, there are heterodox professors even at universities ranked within the top 10, and numerous initiatives for inclusion. So given the wide chasm that needs to be bridged for academic discussion, I think the degree of exclusion is actually rather low.

>So for example Marxian primary material is a critique of past-tense economics.

Marxism has come a long way since Marx, though; a big part of the field today is the applicability of Marxian theories to aspects of modern economies, such as globalization, neoliberalism, imperialism and digital goods. By saying their critique is only aimed at political economy, you're charging them with irrelevance, which to me doesn't seem the case. Being ignored does not mean irrelevance.

Isn't science based on experimentation? I think economics is a science in the same way psychology is a science.

Economics is way more dogmatic.

That's usually a sign that there's too little validated theory beneath the debate. This seems to be the hallmark of all attempts to study complex systems, like psychology and sociology, where in/validation of theory is impossible by experiment and must rely instead on cumulative historical observation, and the interpretation thereof.

it can be based on observation, like we do with space..... we don't usually smash suns into each other, we observe what happens and how well that fits our models of what we think should happen.

Except in astro we also make predictions and theories are accepted when predictions turn out to be right (famously with GR, for example). The problem with macroeconomics is that economists are not capable of meaningfully predicting future macroeconomic indicators (GDP, inflation, whatever). This is why it's not an actual science.

If you can make successful macroeconomic predictions you can get very rich so there are many, many people working on doing so. But you don’t just need to be right, you need to be right first because people with a good model acquire more and more resources from their own growth and from acquiring more outside investment until they reach the limits of the strategy they are using.

Astronomy is not the study of things that resist being predicted and self-modify to be unpredictable upon being successfully predicted.

All that said here are some things we know in macroeconomics; In the long run inflation is caused by an increase in the money supply; If you unexpectedly increase inflation you will have an economic boom as people are fooled by the short run disequilibrium between their expectations of the real value of money and what their nominal money now buys, likewise an unexpected fall in inflation will lead to a recession; You can have at most two of control of inflation, control of the interest rate and a floating exchange rate. If interest rates go up you will attract investment and your currency will appreciate unless you have capital controls. If you want to maintain the value of your currency you have to keep your domestic real interest rate very close to the global real interest rate, unless you have capital controls. If you choose to forego capital controls and have a floating currency you can control interest rates and inflation but you may have large inflows and outflows of capital; If you contract the money supply like the Federal Reserve did after the 1929 stock market crash (30% decline in monetary base, 30%!) you will have a recession.

I agree that it might be fundamentally impossible to make meaningful macroeconomic predictions (because it is self correcting). But this is one of the arguments why macroeconomics might fundamentally not be a science (kind of like the art of writing fiction isn't a real science, although there are many commonalities/themes/etc one can study).

Re your third paragraph. You make many claims which may or may not be correct, but at the end of the day nobody has any kind of track record of prediction long term inflation rates of GDP numbers. This means that there is little value in counterfactual claims (if we did x then y would happen). Every study (such as your allusion to '29) are explanative, not predictive. Explanative studies have relatively little to do with what makes something a science (prediction).

Finally, this is not to say that there is absolutely nothing meaningful in economics. Surely if you arbitrarily set tax rate to 100% or 0% you would have negative consequences. Similarly, if Fed changes current rates dramatically, this would have consequences. It's just for "normal" changes in policy we have basically no predictive power other than something like nearest-neighbor search in historical observation.

The accuracy of GDP prediction, which - remember - amounts to the task of predicting everything there is without having "completed the science", is pretty decent all things considered.

Look for example at GDPnow forecast vs. reality. GDPnow is very spiky, since it changes constantly, but its performance is overall pretty accurate, and during each period its data use more than halves the RMSE. In other words, it has predictive power.

If you look at IMF predictions of world GDP [1] you can see that simply taking last year's value would have had lower error for most years and in average.

[1] -- figure 2 https://www.ft.com/content/60581224-3335-11e8-b5bf-23cb17fd1...

>> Another difficulty is that in many cases (macroeconomics for instance) we cannot do experiments to test theories. This makes it much harder to learn from the data.

I assumed another reason Economics is so hard is because cycles are so long that there are not many to test theories with, especially once you consider unique contexts around specific cycles. Would appreciate if you could opine on this aspect of difficulty?

Also, I'm always amused that after so many years there is still such a two sided dogma on Keynesian vs non Keynesian economics - is one side being difficult or is there really room for debate?

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