Logic 101 and the Terrorist Threat

Wise men are instructed by reason; men of less understanding by experience; the most ignorant by necessity; and beasts by nature. ~ Cicero (106BC – 43BC)

If you think you don't like logic, please bear with me. This theoretical bit is very important and it won't last long. The first thing you learn in formal logic is how to argue from known facts to a true and valid conclusion: the syllogism. It works like this:

• All dogs are mammals
• Rover is a dog
• Therefore – and incontrovertibly – Rover is a mammal

Another example:

• Some dogs are black
• All dogs are mammals
• Therefore – and incontrovertibly – some mammals are black

A common mistake is to reason as follows:

• All dogs have four legs
• A cow has four legs
• Therefore – but erroneously – a cow is a dog

Or:

• Some dogs are dangerous
• Rover is a dog
• Therefore – but erroneously – Rover is dangerous

Why have I bothered to go through all this boring and basic stuff? Because it would seem that the British media including the BBC, of whom I would expect better, have not learnt this elementary lesson.

Consider:

• Some doctors trained in the Middle East are terrorists
• All terrorists are a threat
• Therefore – but erroneously – all doctors trained in the Middle East are a threat

Nevertheless, since the recent car bomb attacks on central London and British airports, we have had reams of coverage about how the NHS should be protecting us from this new and terrible threat. Now that really is dumbing down. And it is frightening in its implication – especially when you consider that the "some" in the argument above actually refers to just seven people.

The number of doctors trained abroad and registered to work in the UK is 128,000 (out of a total of 277,000). Of these, 2169 were trained in Iraq or Jordan (where the suspected terrorists came from). So the threat comes from about one quarter of one percent of doctors from Iraq and Jordan and a minute fraction of all foreign doctors. Suddenly this whole group of people, on whom the NHS relies to staff its hospitals, are put under the spotlight. And the NHS is to be put under even more pressure to scrutinise its staff.

It would be far more productive to try to understand why we are in the position of having to rely on other countries to provide us with 46% of our doctors.

Let's end with a final example of the sort of crummy logic that rules our lives:

• Some Muslims are terrorists
• All terrorists are a threat
• Therefore – but erroneously – all Muslims are a threat

Or how about:

• Some terrorists have been invited to form the government in Northern Ireland
• All terrorists are a threat
• Therefore – ???

That one is too hard for me. Perhaps we need to start again from scratch, use less false logic, and learn from experience instead.

Picture credit:

www.gapingvoid.com/.../archives/003182.html

Comments

[paulus]

Today we have another confirmation that the strategy for dealing with the terrorist threat is not guided by common sense. The chief of Interpol states that there is a clear link between stolen passports and terrorist activity. And yet the British Immigration service is failing to check visitors against a freely available database of stolen passports.
Instead of instituting this cheap and focused procedure it is wasting millions on checking water bottles and other liquids. It is contemplating other expensive broad spectrum measures, which place everyone under suspicion, while ignoring information about stolen passports - crimes already committed.