Science is Ugly…

I’ve been meaning to write something about this post from knzn. The subject matter is whether or not economics is a load of BS or not. Given some of the posts I’ve written here–as well as the name of the blog–you might be inclined to believe that I’m sympathetic to this view. But then, if you thought that, you would be wrong. Although Noah Smith beat me to this subject with a… magisterialpost on the subject, I feel as if I should add my 2 cents.

First off, I am a scientist, and not (only) because I think economics is a science. I also have an advanced degree in physics–I was working on my PhD when I decided to make the switch to econ. So my question to knzn comes from experience; how do you think science is supposed to work? The truth of the matter is that, despite a great (and well-earned) reputation for discovering wonderful things, the real act of doing science is an unbelievably messy process. Researchers make bad assumptions all the time. Those assumptions are then propagated through project after project by a combination of student-teacher relationships, publication pressure, publication bias and politics (I’m probably missing a few). Even in cases of overwhelming evidence, sometimes change comes to these fields only when the original researchers die.

Case in point, everyone these days is familiar (somewhat) with Einstein’s theory of Relativity. What is less well known is that this theory was in competition with another theory called “aether” which was the medium through which light was supposed to travel. This is in direct contrast to Einstein’s theory in which the speed of light is a constant regardless of the relative motions of two observers (two observers moving at different velocities would not generally measure the same value for the speed of light if light is traveling along some medium–imagine for example two observers, one moving in a boat and another anchored at rest, watching waves pass them by. If the moving boat is traveling in the same direction as the waves it may be that no wave crests actually pass by; but the observer at anchor will see waves pass. Water is the “medium” of the waves.) The “Aether” theory lasted for about a century and was supposedly “confirmed” numerous times–for example by the famous Michelson-Morley experiment. Now, its universally accepted that the MM-experiment was the first clear refutation of the aether theory–the original researchers modified the original aether theory to make the whole thing “work” and called the whole project a success, oops. Science comes to the right answer (eventually) despite going down many a blind alley.

Now, you can absorb all this and come to the conclusion that, in fact, physics must be bullsh**t. You could think that, but it’d a little dumb and more than a little lazy.

I don’t want to spend too much time dissecting knzn’s argument–the case I would make only echos Smith’s case, so I’ll leave it to him.

I do want to add a couple points however. First, the “cultural sunspots” argument that knzn makes has its own parallel in quantum physics. When you “observe” particles, they behave quite differently than when you do not. This is a little weird (not least because it makes the observer/observation part of the problem). It’s also entirely true, confirmed in many an experiment (see for example, this… seriously follow the link and learn all about the foundations of quantum computation). So it is just clearly not true that you can’t learn useful things when the underlying things that you’re looking at change when you look at them.

The second point I would make involves the Lucas critique. The Lucas critique does not call bulls**t on macroeconomics. The way that I’d explain (and the way I understand) the dangers of historical data that Lucas is pointing to is through the lens of the age-old scientific debate about reductionism. The need, in other words, to understand “things”, whatever those things happen to be, by studying the constituent parts. The argument in favor of reductionism always follows a Lucas-critique-like logic (i.e. “if you don’t make an effort to study the parts and how they fit together, how will you know how results might change when the underlying system changes” or the like). So you go to the “deep structural parameters” of the problem and see how you do. The thing is there are limits to the approach: you don’t do biology by first “microfounding” it on physics. You could, but that wouldn’t really be a helpful exercise… probably not, at any rate. The key is that this kind of “foundational” work is always useful compared to a world in which you have no knowledge of the microscopic processes involved (which is why reductionism is an important concept in science), but mostly it helps for the purpose of checking previous work or illuminating new phenomena that were unexpected.

For example, the search for microfoundations in the theory of the propagation of light led to the aether theory. Then results that “weren’t quite right” coming out of the investigation of the aether led Einstein to his famous theory of relativity. It could be said that the search for a “microfoundation” for the theory of relativity is a project which is still going on–maybe it’ll take another century.

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  1. July 14, 2014 at 2:25 pm

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