Not Saussure

October 28, 2006

Critical Thinking and undistributed middles

Filed under: Panic, Philosopy — notsaussure @ 2:20 pm

Garry, writing at The Sharpener, takes issue with a prevalent line of muddled argument both among politicians and in the blogoball (© Garry; he says he’s dissatisfied with the other word and this term has the advantage of not being it). He gives a non-specific example thus:

Let’s say that A is a defined characteristic or experience and that X is a particular act. We do a study and discover that every single person who commits act X has first conformed to characteristic A. Can we conclude that characteristic A causes act X?

and then shows how it’s applied in specific cases;

Let’s try a real example. Characteristic A will be defined as those who have smoked cannabis. Act X will be injecting heroin. In that example, studies have shown that almost all injectors of heroin were cannabis smokers first. I’ve seen any number of politicians say that this proves that cannabis is a “gateway drug” but it is a conclusion which cannot be drawn.

Here’s another example. Characteristic A will be defined as those who have smoked cigarettes. Act X will be injecting heroin. In that example, studies have shown that almost all injectors of heroin were cigarette smokers first. Now if you’re a smoker and you think I’m wrong in the previous example, you might be starting to feel unease here. Doesn’t this prove that tobacco is also a ‘gateway drug’? No, it bloody well doesn’t.

It’s also, as he says, used of suicide bombers and Islam:

The fact that all people who commit act X first exhibited characteristic A says almost nothing about any causal relationship which might exist between them. In the first example, the “proof” of a causal relationship seems plausible to some people because it confirms their already held view. In the third, we’ll all instantly dismiss it because we all know it’s ridiculous but the same logical “proof” is used in both cases. If one conclusion is valid then the other must be too.

Here’s a final example. Characteristic A will be defined as those who believe in a version of Islam. Act X will be suicide bombing. In that example, studies have shown that almost all suicide bombers believed in a version of Islam first. (Let’s just put aside whether we believe this claim is true or not and assume that it is for the purposes of this post.) Would that prove that a belief in a version of Islam causes suicide bombing?

No, it bloody well wouldn’t.

Leaving aside the fact that the proposition ‘almost all suicide bombers believe in a version of Islam’ is, as Garry suggests, nonsense — the technique was, if not invented, certainly perfected and used to great effect by the Tamil Tigers, who are a secularist movement drawn from a Hindu Tamil minority in predominantly Buddhist Singhalese Sri Lanka — the fallacy is based, I think, on induction from the classic fallacy of the undistributed middle:

All A’s are C’s.
All B’s are C’s.

Therefore all A’s are B’s.

All teenagers have two legs

All ostriches have two legs

Therefore all teenagers are ostriches.


All potential suicide bombers are Muslims

All Muslims are Muslims

Therefore all Muslims are potential suicide bombers.

This it combines with cum hoc, ergo propter hoc, with this, therefore because of this:

The bigger a child’s shoe size, the better the child’s handwriting.
Therefore, having big feet makes it easier to write.

Which, of course, ignores the possibility that as a child grows up it both gets bigger and gets better at doing various things.

If we accept that most suicide bombers are Muslims, we’d do better to analyse this in terms of

Some extreme political factions fighting against the status quo use suicide bombing as a tactic (because it seems to them the only available weapon).

Some extreme political factions fighing against the status quo comprise radical Islamists.

So some radical Islamists use suicide bombing as a tactic.

If someone who obviously hasn’t heard of the Tamil Tigers, or, indeed, of Russian nihilists who, while they didn’t always blow themselves up in the process, were certainly big on suicidal assassinations (in that they weren’t worried about being caught immediately and executed soon afterwards), objects that, at the moment, it’s only radical Islamists who are using suicide bombing, then the answer is, essentially, so what?

You have to look at the actual circumstances in which particular groups find themselves at a particular time. Someone takes a decision to do something, because of whatever contingent circumstances, and his group go ahead and do it. The USA used the atomic bomb against the Japanese in WW2 and have never used it since. The USSR never used the atomic bomb, even though they could have done. Do we conclude from this that the USSR was run by more humanitarian people than the USA or that American presidents, possibly shocked at what Harry S Truman had done, decided not to repeat the example?

Of course not. We conclude, if we have any sense, that the USSR never, and the USA never subsequently, found themselves in a position where using their nuclear weapons seemed the least bad option.

That’s the trouble with these ‘culture wars’ arguments — they deal with abstractions, readily divorced from the real situations in which people find themselves. That’s probably why they’re so popular with particular political commentators.

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