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Douglas_Knight comments on What false beliefs have you held and why were you wrong? - Less Wrong Discussion

28 Post author: Punoxysm 16 October 2014 05:58PM

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Comment author: JoshuaZ 17 October 2014 12:34:00AM *  10 points [-]

I believed that the composition of a rational rotation of a sphere and another rational rotation of a sphere will be rational. (By a rational rotation I mean a rotation of a sphere around some axis which in radians is a rational multiple of pi, and thus will end up putting the sphere back where it started if you apply it enough.) Counterexample: Two 30 degree rotations each around a different axis with the two axies perpendicular to each other. I believed this because I was too used to thinking about the two-dimensional case, where it is trivially true.

Until very recently, I was convinced that it was extremely unlikely that any form of adiabatic quantum computing would have any chance at working at providing speedups, either asymptotically or practically. This belief came to a large extent as what was in retrospect an irrational reaction to the junk and bad hype that has been repeatedly coming from D-Wave. I changed my position when Scott Aaronson made this comment (comment number 25).

More mind-killing territory: Until about 3 days ago, I was convinced that claims that mass shootings were increasing in the US were due purely to media scare tactics and general human tendencies to see things as getting worse. This article made me strongly update against that. Since then, I've seen this response and this one which were both deeply unpersuasive as responses go.

Even more potential mindkilling: Having read more of Slatestarcodex, I've become convinced that he's correct that there really is a substantial fraction of what self-identifies as the "social justice" movement, primarily in an online context, that really is toxic, and that the rest of the left and the serious, sane part of the SJers aren't doing enough to call them out on it. On the flipside, "Gamergate" has convinced me that there's still a very real need for a vocal feminist movement, and that latent misogyny is still pretty common. Edit: To specify what this means in an operational sense, that there are a lot of SJers out there who are making personal attacks or calls for censorship against those with whom they disagree.

I was convinced in 2008 that Obama was going to be good for civil liberties. I don't think I need to discuss in any detail why that was wrong or how I got convinced otherwise, since the reasons should be pretty obvious.

Comment author: Douglas_Knight 19 October 2014 06:02:30PM 2 points [-]

What is unpersuasive about the responses to Mother Jones?

They're exactly what I thought when I read it. Actually, I had a more specific thought: what changed in 2011 is that they started collecting data live, rather than through archives. Of course, rejecting a data set because it was produced by hand in an ad hoc manner does not give you a replacement data set and thus does not produce an actual analysis. But the Reason link suggests Duwe's data as a replacement. Since he starts with official data and only uses media coverage to fill in details, he isn't subject to temporal bias.

Comment author: JoshuaZ 20 October 2014 02:55:19PM 0 points [-]

What is unpersuasive about the responses to Mother Jones?

I agree that Duwe's point is the closest thing there to a decent argument against MJ's data. But I think the accusation that there data is "cherrypicked" is not reasonably supported. The entire paragraph in Siegel's piece where he argues for this is essentially ignoring that what they are using is what fits closely with the common intuition of what is a mass shooting. The only one which one could plausibly take out of that set is Fort Hood but it doesn't alter the data very much.

Most of Siegel's points are correct but not relevant to the question of increases of shootings. For example, he's correct that there's a serious measuring issue with whether shootings are stopped by others with weapons, and he's also correct that even if the trend identified by MJ is accurate it is still a tiny fraction of total crimes and will remain so, but that's not actually relevant to evaluating the central claim.

Comment author: Douglas_Knight 20 October 2014 04:36:38PM *  4 points [-]

What about the methodology of starting with news reports? These have strong biases that probably change by time. And how did they locate decades old news reports? A recency bias is to be expected. (Added: Duwe has a paper about this!)

Their definition is pretty reasonable, except for the part where they make tons of exceptions. The examples they gave of the exceptions that they made sound intuitive, but what about all the exceptions that they didn't talk about? Why didn't they include the Ridgewood Postal murders? Since they don't actually have a consistent rule, it's impossible to decide if they applied it to this case, or if the actual criterion was that it was too old.

Added: I tried spot-checking a few examples from Duwe's book against the MJ list. On pages 115-116 he lists 12 high profile workplace mass shootings. In addition to Ridgewood, they omit Alan Winterbourne and Willie Woods, both very straight-forward examples. If they miss these high profile examples, why would you expect them to reliably find others?

Comment author: JoshuaZ 21 November 2014 04:11:37PM 1 point [-]

Thinking about this more, I think you are correct. The data is much too spotty to make a strong conclusion.