An argument that can’t possibly make sense

Tyler Cowen writes:

Texas has begun to enforce [a law regarding parallel parking] only recently . . . Up until now, of course, there has been strong net mobility into the state of Texas, so was the previous lack of enforcement so bad?

I care not at all about the direction in which people park their cars and I have no opinion on this law, but I have to raise an alarm at Cowen’s argument here.

Let me strip it down to its basic form:

1. Until recently, state X had policy A.

2. Up until now, there has been strong net mobility into state X

3. Therefore, the presumption is that policy A is ok.

In this particular case, I think we can safely assume that parallel parking regulations have had close to zero impact on the population flows into and out of Texas. More generally, I think logicians could poke some holes into the argument that 1 and 2 above imply 3. For one thing, you could apply this argument to any policy in any state that’s had positive net migration.

Hair styling licensing in Florida, anyone?

P.S. I’m not trying to pick on Cowen here. Everybody makes mistakes. The most interesting logical errors are the ones that people make by accident, without reflection. So I thought it could be helpful to point this one out.

P.P.S. Commenters suggest Cowen was joking. In which case I applaud him for drawing attention to this common error in reasoning,

9 thoughts on “An argument that can’t possibly make sense

  1. "I'm not trying to pick on [Person X]" appears too frequently on this blog. Pick on him, for cryin' out loud! He said something totally idiotic! You beat yourself up endlessly for publishing a false theorem, and yet you bend over backwards to avoid implying that just because somebody has said something stupid, that person has said something stupid.

    By the way, you can stop beating yourself up about that false theorem, too: it's not like it had any impact, since nobody believed it anyway.

  2. Um, I'm pretty sure that Cowen's post was firmly tongue-in-cheek. I would have thought that saying "the resulting policy uncertainty adds to our current output gap" about a parallel parking law would have been a dead give away.

  3. Cowen's post was *obviously* tongue-in-cheek. The joke is on you. And the statement regarding the "most interesting logical errors" applies to you, not him.

  4. Nobody would seriously say " And is not a car, if parked for long enough, infinitely dangerous in any case?"

  5. Obviously, if parallel parking had been enforced those unable to conform would have driven on to another state?

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