Monday, July 06, 2015

Why the data do not support profiling Muslims

I'm going to go into some detail here about why the recently published data about extremist violence do not support profiling Muslims.  I thought this would be obvious, but apparently it isn't.

Let me start by summarizing the (fallacious) argument for profiling Muslims.  It goes something like this: Obviously, most extremist violence in the world is undertaken by Muslims.  In fact, by the recent numbers, Muslims are about 40 times more likely to engage in extremist violence than non-Muslims.  So it is obviously we should be profiling Muslims rather than non-Muslims.

When couched in those terms it seems like a pretty compelling argument, doesn't it?  But here is a completely equivalent argument, which is (I hope!) obviously bogus:
Self-identified atheists are about 2.4 percent of the U.S. population.  If we assume that these are more or less uniformly distributed across the country, then there are probably about 1500 self-identified atheists living in Chapel Hill, North Carolina.  (More likely the number is lower, but let's be conservative here.)  One of these, Craig Hicks, shot and killed three Muslim students in February of 2015.  So about 0.06% of self-identified atheists living in Chapel Hill have committed acts that could reasonably be characterized as terrorism.  So the concentration of terrorists among atheists in Chapel Hill is about 200 times greater than the concentration of terrorists among Muslims in the U.S.  Therefore we should be profiling Chapel Hill atheists in order to improve our odds of catching terrorists.
Hopefully I don't have to convince you that this argument is fallacious, and yet it is structurally identical to the argument for profiling Muslims.  So why does it seem so much more compelling when applied to Muslims?

Part of the problem is that there really is a connection between terrorism and Islam.  Most of the world's terrorists are Muslims.  However, it is emphatically not the case that most of the world's Muslims are terrorists!  And if your goal is to find terrorists (as opposed to figuring out what religion a terrorist happens to be) that is what matters.

The real problem with all of these arguments is that terrorists are actually quite rare, and in the U.S. they are extremely rare.  There have been 26 documented terrorist attacks in the U.S. since 9/11.  That's less than two a year.  So out of 300,000,000 people, less than two of them will (on average) commit a terrorist act in any given year.

The problem is that when the numbers are that small they become very sensitive to outliers and boundary effects.  For example, I've been using the number-of-incidents as my statistic, but the NewAmerica web site actually headlines the body count instead.  If we use body count, things look worse for the Muslims: the ratio of Muslim to non-Muslim violence grows from 37% to 54%.  However, note that fully half of the Muslim body count is due to a single event: the Fort Hood shooting.  If we ignore this one event as an outlier, the body count ration plummets to 27%.  Even if we also ignore the Charleston church shooting as an outlier on the non-Muslim side, the ratio is still only 33%.

But all of these numbers are red herrings.  They will help you figure out after the fact whether a particular terror victim was likely killed by a Muslim or a non-Muslim, but that's not really what we want to know.  What we want to know is how to improve our odds of catching terrorists before they commit acts of terror, n'est pas?  And for that goal, these numbers don't help at all.

The reason they seem to help is that the rate of terrorism among American Muslims is 37 times higher than it is among American non-Muslims.  That seems like a compelling number, until you recall that the incidence of terrorism among Chapel Hill atheists is 200 times higher than it is among American Muslims, and 7400 times higher than among the population at large.  I hope I don't have to convince you that profiling Chapel Hill atheists will probably not have a positive impact on the problem of terrorism, despite the overwhelmingly higher rate of terrorists among them.  Yes, profiling Muslims might increase your odds of finding terrorists from 0.0000001 to 0.0000037.  But those are still mighty poor odds.  And the resentment that you would instill in the American Muslim community might well cause more terrorist acts than the profiling prevents!

So what should be done instead?  Surely we have to do something about terrorism?

Well, no, actually we don't.  The fact of the matter is that terrorism is really not that big of a problem in the U.S.  The total body count since 9/11 is only 74, or only about five people a year.  About that many people die in car crashes every hour.  Even if we include 9/11 and Oklahoma City that's still only about 150 people a year, less than two days worth of traffic fatalities.

Of course, we really do want to keep weapons of mass destruction out of the hands of crazy people.  But your ordinary run-of-the-mill terrorism of the sort that anyone can accomplish with readily available light ordinance is just not that big of a problem, despite the splashy headlines.  It is hard to imagine a more irrational policy than profiling Muslims to prevent terrorism.

15 comments:

Luke said...

What if there were enough Chapel Hill instances such that one could statistically establish that an atheist is 200x as likely to commit terrorism as a Muslim, and 7400 times as likely as a typical American? Does your argument still stay exactly the same? It seems to me that your argument is intuitively predicated upon Chapel Hill not well-representing the true situation, that the invalidity of it is supposed to be due to hasty generalization.

Ron said...

> Does your argument still stay exactly the same?

Yes, because the odds of a typical American being a terrorist is vanishingly small. On average, there have been fewer than two domestic terrorist acts each year since 9/11. So the odds of any particular American committing a terrorist act in any given year is <0.0000001%. Improve those odds even by a factor of 7400 and you're still looking at <0.001% that a person in your target group will be a terrorist -- and even that is only if all of your errors are type-1 errors. If you have any false negatives then your odds start collecting zeros again.

To get your odds up to even 1% (i.e. 99 false negatives for each true positive) you would somehow need to narrow your focus down to fewer than 200 people. There are three million Muslims in the U.S. so focusing on them you are off by four orders of magnitude.

> the invalidity of it is supposed to be due to hasty generalization.

No, it's more like affirming the consequent:

https://en.wikipedia.org/wiki/Affirming_the_consequent

If someone is a terrorist, then they are likely to be a Muslim. It does not follow that if someone is a Muslim that they are likely to be a terrorist. (And actually, in the U.S., even the premise is not true.)

The Chapel Hill situation is an extreme example of this: if someone is a terrorist in Chapel Hill, then they are 100% guaranteed to be an atheist (based on current data). It does not follow that if someone is an atheist in Chapel Hill that they are 100% guaranteed to be a terrorist.

Luke said...

> Yes, because the odds of a typical American being a terrorist is vanishingly small.

I don't understand why you keep bringing up this kind of argument. Profiling, according to my understanding, does not say that "Muslim = terrorist", "Jew = thief", etc. Doing this would be stereotyping. Instead, the point of profiling seems to be to best expend your resources, by preferring the profiled group for increased scrutiny, ceteris paribus—because ceteris paribus, members of that group are more likely to be guilty.

> It does not follow that if someone is a Muslim that they are likely to be a terrorist.

I thought the argument was "more likely", not "likely".

Ron said...

> I don't understand why you keep bringing up this kind of argument.

Just because one course of action is better than another it does not follow that it is a good course of action. They might *both* be horrible courses of action.

> ceteris paribus

But all else is *not* equal. Profiling Muslims has a very significant societal cost, namely, the marginalization and stigmatization of three million innocent people.

Now, it *might* be arguable that marginalizing and stigmatizing three million innocent people is a price worth paying to increase the chances of catching a terrorist from one number effectively indistinguishable from zero to a somewhat larger number that is still effectively indistinguishable from zero. But it's *certainly* not the slam-dunk that Harris claims.

Luke said...

> Just because one course of action is better than another it does not follow that it is a good course of action. They might *both* be horrible courses of action.

I don't see how this is a response; as far as I can tell you produced a straw man. Has Sam Harris ever said that even 1% of Muslims are terrorists—not to mention 100%?

> But all else is *not* equal. Profiling Muslims has a very significant societal cost, namely, the marginalization and stigmatization of three million innocent people.

That's not the function of ceteris paribus in my statement; I was talking about facts which bear on the likelihood that a person will be of interest to law enforcement with regard to terrorist activity. I agree that there is "a very significant societal cost". It must be balanced with other costs. For example, recall:

> Luke: Nowhere in either article did I see:
>
>     (1) the population sizes each group is drawn from
>     (2) profiling mechanisms in-place
>     (3) thwarted plots with estimates of success and body count

Several terrorist plots by ISIS were thwarted this recent July 4. One good way to figure out whether someone is part of ISIS is whether that person is Muslim. That isn't a perfect measure—someone could have serious beefs with America without being Muslim—but as I've said before, profiling need only be probabilistically correct, not perfectly correct. So it would seem that (2) and (3) are quite relevant to this discussion. I will bet that some sort of profiling based on Muslim belief already happens. You could ask Americans whether they'd like to reduce that "very significant societal cost", at the cost of some American lives.

> Now, it *might* be arguable that marginalizing and stigmatizing three million innocent people is a price worth paying to increase the chances of catching a terrorist from one number effectively indistinguishable from zero to a somewhat larger number that is still effectively indistinguishable from zero. But it's *certainly* not the slam-dunk that Harris claims.

Is it the case that necessarily, "profiling" ⇒ "marginalizing and stigmatizing"? For example, profiling at an airport does inconvenience some and convenience others (a young women with young children is very low risk), but it is not clear that this rises to "marginalizing and stigmatizing". Now, I'm aware of profiling like NY's stop-and-frisk practices, but it's not clear that it actually works, that the math works out for optimally allocating law enforcement time. This is not a perfect world, as you noted: "The resources you put towards preventing A are resources you can no longer deploy to prevent B."

Ron said...

> Has Sam Harris ever said that even 1% of Muslims are terrorists—not to mention 100%?

No. His argument (as best I can make it out -- it's pretty incoherent as he presents it) is: most terrorists are Muslims (which is true), therefore it makes no sense to expend resources searching white people at airports (which is false).

> That's not the function of ceteris paribus in my statement;

What can I say? All the latin I know is what I read in wikipedia:

"Ceteris paribus or caeteris paribus is a Latin phrase meaning "with other things the same" or "other things being equal or held constant"

> One good way to figure out whether someone is part of ISIS is whether that person is Muslim.

No, that's not true! You are making exactly the same mistake here. The vast majority of Muslims are not "part of ISIS" (whatever that might mean). Even if there were 100,000 people in the world who could reasonably be called "part of ISIS" (the actual number is almost certainly lower) there are a billion Muslims, so P(ISIS|MUSLIM) = 0.01% so the odds of a false negative are 99.99%. (And almost certainly much higher.) I would not call that a "good way" to figure out whether someone is "part of ISIS."

A much better way to figure out if someone is "part of ISIS" is if they 1) profess to be part of ISIS or 2) correspond with someone who professes to be part of ISIS. That is how they actually caught the alleged terrorists. Why did this work? Because 1) there is an actual plausible *causal* link between corresponding with people who profess membership in ISIS and committing terrorist acts and 2) there are only "a few dozen" such people in the U.S. so your odds of a false positive go WAY down, like well below 99%. Also, now you are profiling people based on their ACTIONS rather than their beliefs. Happily, this appears to be what the government actually did. Happily, not all members of law enforcement are idiots.

> Is it the case that necessarily, "profiling" ⇒ "marginalizing and stigmatizing"?

Yes. As the full beneficiaries of white privilege it is nearly impossible for the two of us to fully understand this, but when you grow up knowing that people suspect you are a criminal simply because of the color of your skin or the way you dress or your religious beliefs, that has a corrosive effect on your soul.

Luke said...

> No. His argument (as best I can make it out -- it's pretty incoherent as he presents it) is: most terrorists are Muslims (which is true), therefore it makes no sense to expend resources searching white people at airports (which is false).

Do you really think he believes this? Perhaps he believes that we should expend more resources searching Arabs than white people. More accurate would be to use all the ways we can discern whether someone is Muslim (we do have more than skin color to go on). I don't think it is fair to treat succinct sound-bites of a person as his/her actual argument. Surely you see how doing this is antithetical to idea-ism? It is not infrequent for people to state things succinctly such that they're strictly incorrect, but that a much better version of the idea can be ferreted out in a pretty obvious fashion.

> Luke: One good way to figure out whether someone is part of ISIS is whether that person is Muslim. That isn't a perfect measure—someone could have serious beefs with America without being Muslim—but as I've said before, profiling need only be probabilistically correct, not perfectly correct.

> Ron: No, that's not true! You are making exactly the same mistake here. The vast majority of Muslims are not "part of ISIS" (whatever that might mean).

I was a bit ambiguous, but I don't think it's too unreasonable to interpret what I said as:

     (A) ¬Muslim ⇒ ¬ISIS

, and not:

     (B) Muslim ⇒ ISIS

, especially since I said "Has Sam Harris ever said that even 1% of Muslims are terrorists—not to mention 100%?" Note here that the '⇒' in (A) is actually just an approximation, but not necessarily a useless approximation.

> Yes. As the full beneficiaries of white privilege it is nearly impossible for the two of us to fully understand this, but when you grow up knowing that people suspect you are a criminal simply because of the color of your skin or the way you dress or your religious beliefs, that has a corrosive effect on your soul.

Wait, is this proper use of profiling? If one mathematically optimizes one's resources, then someone would have to test positive for more than just the 'Muslim' indicator to merit increased attention by law enforcement. You would have to "just happen" to look like a terrorist in a number of ways, in order to get to a decent probability. Just being Muslim (for sure—we need not be probabilistic here) is not enough.

Ron said...

> Do you really think he believes this?

I have no idea what Sam Harris really believes. (This is a big part of the point I am trying to make, BTW.) All I know is what he said. And what he said is (among other things):

"Every moment spent frisking the Mormon Tabernacle Choir subtracts from the scrutiny paid to more likely threats. Who could fail to understand this?"

I think "it makes no sense to expend resources searching white people at airports (and this is a no-brainer)" is a not-unreasonable paraphrase of this statement.

> (A) ¬Muslim ⇒ ¬ISIS

This is only true because ISIS explicitly rejects non-Muslims. It's a vacuous observation, kind of like observing that if someone is not a Mormon then they are (almost certainly) not a member of the Mormon Tabernacle Choir. You've created a self-fulfilling prophecy simply by choosing to focus on a group that only allows Muslims to join. You could just as well have written:

~WHITE => ~NAZI

to support an argument that we should profile white people to find Nazis.

> Just being Muslim ... is not enough.

OK, well, at least you're conceding this much. This is progress.

So let me point out two things:

1. Harris never says this. He says: profile "Muslims, or anyone who looks like they could conceivably be Muslim", period, end of story.

2. Suppose we actually enumerate the "other things" that you would have to add to "Muslims, or anyone who looks like they could conceivably be Muslim" in order to make the program effective. Once we have this list, does adding "Muslims, or anyone who looks like they could conceivably be Muslim" really add any value? For example: suppose we profile on "people who profess sympathy with ISIS, and their direct correspondents." How much additional value do we get by adding "Muslims, or anyone who looks like they could conceivably be Muslim"? Do we really want to eliminate someone from scrutiny if they're exchanging emails with a self-professed ISIS member simply because the correspondent is (say) a white supremacist rather than a Muslim?

Luke said...

> I have no idea what Sam Harris really believes. (This is a big part of the point I am trying to make, BTW.) All I know is what he said. And what he said is (among other things):
>
> "Every moment spent frisking the Mormon Tabernacle Choir subtracts from the scrutiny paid to more likely threats. Who could fail to understand this?"
>
> I think "it makes no sense to expend resources searching white people at airports (and this is a no-brainer)" is a not-unreasonable paraphrase of this statement.

According to your paraphrase, it is impossible that terrorists could infiltrate the Mormon Tabernacle Choir. I doubt Harris believes such a thing. Therefore, I am skeptical that your paraphrase is reasonable. It would appear that Harris is exaggerating to make a point. Do you think that doing so is never a valid rhetorical tactic?

> This is only true because ISIS explicitly rejects non-Muslims. It's a vacuous observation [...] You've created a self-fulfilling prophecy simply by choosing to focus on a group that only allows Muslims to join.

If the chance of a given terrorist being from ISIS is sufficiently high, I don't see how it is vacuous at all. I think reasoning with thwarted terrorist attempts is important, and I linked to a news article claiming that several July 4 ISIS terrorist attempts were thwarted. I don't have full access to US intelligence on how many acts of terror total were thwarted and whether they were ISIS or not, Muslim or not. So, I made a guess. If you want, we can abandon this particular tangent since it is not rigorous to the level of Caltech's [sadly, prior] Ma1a standards. I can probably be as rigorous as you require, although I will ask that you adhere to the same standards of rigor.

> Luke: Just being Muslim [...] is not enough.

> Ron: OK, well, at least you're conceding this much. This is progress.

I'm sorry, but the only progress made here is you switching from an absolutely ludicrous model of my position, to something better. The prior, ludicrous model is flatly contradicted by this comment of mine. Really, I have no idea how you think I just made a concession when I previously wrote "non-Muslim terror acts per million".

Luke said...

> > Just being Muslim ... is not enough.

> 1. Harris never says this. He says: profile "Muslims, or anyone who looks like they could conceivably be Muslim", period, end of story.

From In Defense of Profiling:

>> We should profile Muslims, or anyone who looks like he or she could conceivably be Muslim, and we should be honest about it. And, again, I wouldn’t put someone who looks like me entirely outside the bull’s-eye (after all, what would Adam Gadahn look like if he cleaned himself up?) But there are people who do not stand a chance of being jihadists, and TSA screeners can know this at a glance.

How is his second sentence not a statement that someone who looks like him could be a terrorist? The story very much continues after the first sentence, which you quoted.

> 2. Suppose we actually enumerate the "other things" that you would have to add to "Muslims, or anyone who looks like they could conceivably be Muslim" in order to make the program effective. Once we have this list, does adding "Muslims, or anyone who looks like they could conceivably be Muslim" really add any value?

That's the question, and you've presented absolutely zero evidence or reason to think it likely that no value is added. You noted that the various factors aren't necessarily orthogonal, which I am happy to grant. Covariance between factors will almost certainly be nonzero.

> Do we really want to eliminate someone from scrutiny if they're exchanging emails with a self-professed ISIS member simply because the correspondent is (say) a white supremacist rather than a Muslim?

Absolutely nothing in Sam Harris' argumentation seems to lead to such a situation, making this seem like a straw man. Something he actually says is that patting down 5-year-olds is probably a waste of TSA resources. Do you disagree with this?

Ron said...

> I doubt Harris believes such a thing.

It doesn't really matter what he believes. What matters is that he specifically cites the MTC as an example of a group that should be exempt from scrutiny.

> If the chance of a given terrorist being from ISIS is sufficiently high, I don't see how it is vacuous at all.

You have to stop mixing up branches of the argument. You wrote:

"One good way to figure out whether someone is part of ISIS is whether that person is Muslim."

In this branch of the argument you were not talking about terrorists, you were talking about ISIS. There is some significant overlap here, but they are not synonymous. ¬Muslim ⇒ ¬ISIS is a different claim than ¬Muslim ⇒ ¬Terrorist.

> How is his second sentence not a statement that someone who looks like him could be a terrorist?

[shrug] Yes, he's conceding (probably for the sake of political correctness, not because he really believes it) that he looks like he could conceivably be a Muslim. The fact is that EVERYONE looks like they could conceivably be a Muslim. So there are only two possibilities: 1) Harris's proposal is vacuous or 2) there are people that he believes look like they could not conceivably be Muslims and can therefore be eliminated from scrutiny. And he specifically cites the Mormon Tabernacle Choir (and Mennonites!) as examples of such people. Personally, I have no idea how to tell a Mennonite by sight, but I have a pretty good idea what someone means when they talk about the MTC: they mean white folks.

> Something he actually says is that patting down 5-year-olds is probably a waste of TSA resources. Do you disagree with this?

I think patting down anyone is a waste of resources because I think terrorism is not a serious problem. But if I suspend disbelief and accept for the sake of argument that it's a serious enough problem to warrant patting anyone down, then I don't see any reason to exclude five-year-olds. It's true that a five-year-old is probably not going to take the initiative to strap a bomb to him or herself, but what is to stop their parents from doing it?

https://www.foreignaffairs.com/articles/middle-east/2015-02-09/rise-child-terrorist

Luke said...

> It doesn't really matter what he believes.

I don't see how it is legitimate to treat a person or his/her arguments this way.

> You have to stop mixing up branches of the argument.

If ISIS threats are significant enough compared to the total threat, the correct version of my argument (I will only carefully go through our conversation if necessary) seems just fine. We're looking for ways for law enforcement to make statistically better guesses, not trace lines of necessary causation.

> Yes, he's conceding (probably for the sake of political correctness, not because he really believes it) that he looks like he could conceivably be a Muslim.

This looks like a ploy to delegitimize Harris' argument based on scant evidence. The people he actually wants to anti-profile include three-year-olds, eighty-year-olds, and "members of the Mormon Tabernacle Choir". Statistically, these people seem less likely to be terrorists (or unwitting weapons of terrorists) than those that law enforcement can reasonably identify as Muslims.

> I think patting down anyone is a waste of resources because I think terrorism is not a serious problem.

As to numbers of deaths I would agree, but the resultant psychological fear of 9/11 legitimated stuff like the Patriot Act. You have called the Patriot act "the greatest threat to our individual freedoms ever" and said it "bring[s] us closer to being a totalitarian state than at any time in our history".

I would also like to point out the decline in Americans trusting each other in the US, from 56% in 1968 → 33% in 2014. If there's any antidote to fear, it is trust. If we don't want the government surveilling citizens, then (i) citizens need better ties to one another, reducing the chance that violence is seen as the best option; (ii) citizens need to report suspicious behavior. Otherwise, do you really think we can avoid Patriot Act #2?

Ron said...

>> It doesn't really matter what he believes.

> I don't see how it is legitimate to treat a person or his/her arguments this way.

Huh? I think it's not only legitimate, but *respectful* to judge someone based on what they actually say rather than on what you think they believe.

> We're looking for ways for law enforcement to make statistically better guesses

No. Merely "better" is not good enough. Better than horrible can still be horrible. What we should be aiming for is not just *better* guesses, but actually *good* guesses, i.e. guesses where the benefits substantially outweigh the costs.

> This looks like a ploy to delegitimize Harris' argument based on scant evidence.

Sorry, scant evidence is all I have. Part of the problem with Harris's program is that he never really defines what it is. He never says how he proposes that law enforcement determine whether someone "looks like they could conceivably be Muslim." All he does is provide a few counterexamples (Mennonites, the MTC), and then asks us to extrapolate from there with a nudge and a wink. Because surely everyone just *knows* what a Muslim looks like, don't they? (Publius certainly seems to think so.)

> You have called the Patriot act "the greatest threat to our individual freedoms ever" and said it "bring[s] us closer to being a totalitarian state than at any time in our history".

My goodness, I wrote that twelve years ago! Are you actually reading my entire blog? I'm flattered!

> citizens need better ties to one another

Yes, indeed! And I don't think singling out a particular minority group for baseless suspicion is the best way to achieve that.

Instead of profiling *Muslims* how about profiling (say) people who openly advocate violence against innocent people? That would have netted you *both* Mohammad Youssef Abdulazeez *and* Dylann Roof *and* Alexander Ciccolo too. Also, I suspect there are a lot fewer than 1 million such people, so you start with a better prior. And you have the added bonus that you're singling out people based on what they *do* rather than their faith or their physical appearance. It seems like a win-win to me.

Luke said...

> I think it's not only legitimate, but *respectful* to judge someone based on what they actually say rather than on what you think they believe.

There is no such thing as "what they actually say" having meaning; there is:

     (1) what a person meant to communicate
     (2) the words that person used
     (3) how you interpreted those words

When the result of (3) is absurdity, you have some choices. You can assume that the person really did make an absurd point. But you can also look for "nearest neighbors" to what that person said which do make some sense. I find that this approach frequently demonstrates that the error was located at (3) instead of (1). In other times, the error was at (1) but was inconsequential. Some times yes, there is a deep error at (1). But I work pretty hard to ensure that this is the most likely explanation.

I will note, by the way, that when it suited your argument, you were quite willing to say that the words Harris used were not what he meant:

> Ron: Yes, he's conceding (probably for the sake of political correctness, not because he really believes it) that he looks like he could conceivably be a Muslim.

That was a "nearest neighbor" to what he actually said which construes him as making an absurd argument. You did not work with what Harris "actually [said]".

> No. Merely "better" is not good enough. Better than horrible can still be horrible. What we should be aiming for is not just *better* guesses, but actually *good* guesses, i.e. guesses where the benefits substantially outweigh the costs.

It is an entirely different argument that Harris' plan would be better but not worth the cost in discrimination, than whether his plan would be better, discrimination concerns be damned. Are you making one or both arguments?

> My goodness, I wrote that twelve years ago! Are you actually reading my entire blog? I'm flattered!

Nope, Google's site: operator is quite helpful. Has your position since changed?

> Instead of profiling *Muslims* how about profiling (say) people who openly advocate violence against innocent people?

Avoiding the unsubstantiated exclusive 'or', I wouldn't be surprised if the federal government does profile based on this. That seems pretty logical to me.

Ron said...

> Are you making one or both arguments?

I got lost in all the antecedents.

My position is that Harris's program of profiling "Muslims, or anyone who looks like they could conceivably be Muslim" is a Really Bad Idea (tm) for multiple reasons. Those reasons include, but are not limited to:

1. There is no way to tell whether someone is a Muslim by their appearance.

2. Even if you could tell whether someone is a Muslim by their appearance, the benefit of profiling Muslims is negligible because the Bayesian prior on a Muslim being a terrorist is very nearly zero.

3. Even if the benefit of profiling Muslims were substantially distinguishable from zero, the societal costs of profiling Muslims is extremely high because it would marginalize and stigmatize Muslims, the vast (vast!) majority of which are not terrorists, and indeed innocent of any crime.

4. Even if the incremental benefit of profiling Muslims outweighed the very high societal costs (and please take note that we are now three levels deep in our suspension of disbelief) it would STILL not be wise to adopt Harris's program if our goal is to prevent terrorism. Why? Because not all terrorists are stupid, and to protect against terrorism you need to guard against the smart terrorists as well as the stupid ones. And the smart ones will observe that the authorities are not profiling people who fit a certain profile, and actively recruit people who fit that profile to carry out the next attack. The 9/11 terrorists did not wear dishdashas. They (mostly) did not have beards. They did not go through security chanting "Allahu akbar". *If* you are going to search people at airport security (and I do not even concede that much, but we're suspending disbelief here) and we're going to entertain intuitive hand-wavy arguments to decide who to look at, then one could argue that it actually *does* make sense to randomly search old people and children and even Mennonites and members of the MTC because that will discourage the smart terrorists from trying to employ such people as weapons delivery vectors.

Now, AFAICT, you are defending Harris on two grounds:

1. Profiling Muslims is 37x as effective as not profiling Muslims. That's simply not true (because you ignore the false negatives you generate, c.f. Dylann Roof). And even if it were true, you are still almost certainly not going to win the lottery even if you buy 37 tickets instead of just one or zero.

2. Maybe Harris meant something non-stupid and non-xenophobic by what he said, and it is incumbent on me to try to figure out what that might be before criticizing him. To that I have two answers: 1) I actually have tried to extrapolate what Harris said to some non-stupid and non-xenophobic place and failed. And 2) when you are a professional writer, and particularly when you are a professional writer who purports to advocate reason and rationality, the burden is on you to make yourself clear, and not on your audience to try to wring meaning out of statements that are stupid and xenophobic when taken at face value. Because, well, that's your job.

> Has your position since changed?

Calling the Patriot act the "greatest threat ... ever" may have been a tad hyperbolic. But it certainly makes my top 10 list.