Friday, July 27, 2012


One thing that Paul Krugman says rather frequently is that he isn't particularly smart, but that he has the right model (here's a recent example). I think that this is a useful way to metathink, that is, think about thinking. Having some model of how the world works and applying that to problems is extremely useful.

What made me think of this today was a post on the Beer Advocate forums (I'm not going to bother to link it) where someone stated that he wished a brewery would put electrical tape around the cap of their growlers, because he's had them go flat on him. (For the unfamiliar, a growler is a large, usually 1/2 gallon, container of beer. It's typically sealed either with a screw cap or with a flip-top with a rubber gasket.)

Why did this make me think of models? The main reason is that the only way you could think that electrical tape would help make a gas-tight seal is if you have some truly bizarre conception of how the world works. First, it's terrible tape in general and doesn't stick very well to even a smooth, flat, dry surface. Second, when it does stick it's not even close to gas-tight at any reasonable pressure. Third, growlers are irregalar and frequently wet, making it even more useless since it's impossible to actually get it to stick across the gas's escape path.

The best part, to me, is when people think that electrical tape can prevent a leak. How would this even work? When you tape it there's some room between the tape and the growler, and the air in there is at atmospheric pressure. A leak can still develop, even if you actually made a perfect seal with the tape (which you didn't). If the tape is perfect it will contain the leak and stop it from losing too much liquid, but by that point most of the damage has been done anyway.

I believe that this obviously terrible idea persists because people have bad models and fundamentally misunderstand the way the world works, or they see other people do it and just don't question it. And I think that you can use the model view of the world to understand why people think weirdly.


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