Tag Archives: false analogy

Consent to risk fallacy

A common argument against counter-terrorism measures is that more people are killed each year by road accidents than by terrorists.  Whilst this statistic may be true, it is a false analogy and a red herring argument against counter-terrorism. It also ignores the fact that counter-terrorism deters and prevents more terrorist attacks than those that are eventually carried out.

This fallacious argument can be generalised as follows: ‘More people are killed by (fill-in-the-blank) than by terrorists, so why should we worry about terrorism?’  In recent media debates, the ‘blank’ has included not only road accidents, but also deaths from falling fridges and bathtub drownings.  However, for current purposes let us assume that more people do die from road accidents than would have died from either prevented or successful terrorist attacks.

Whenever we travel in a car, almost everybody is aware that there is a small but finite risk of being injured or killed.  Yet this risk does not keep us away from cars.  We intuitively make an informal risk assessment that the level of this risk is acceptable in the circumstances.  In other words, we consent to take the risk of travelling in cars, because we decide that the low level of risk of an accident does not outweigh the benefits of car transport.

On the other hand, in western countries we do not consent to take the risk of being murdered by terrorists, unless we deliberately decide to visit a terrorist-prone area like Syria, northern Iraq or the southern Philippines.  A terrorist attack could occur anywhere in the West, so unlike the road accident analogy, there is no real choice a citizen can make to consent or not consent to the risk of a terrorist attack.

The Consent to risk fallacy omits this critical factor of choice from the equation, so the analogy between terrorism and road accidents is false.



Filed under Logical fallacies

Argument from analogy

Analogical reasoning is one of the most common methods by which human beings attempt to understand the world and make decisions.  We seem to have evolved with a propensity to find patterns in things and events, even when no such patterns exist.

Suppose, for example, that I am thinking about buying a new washing machine.  I’m very likely to speak with other people who have recently bought new washing machines, noting their experiences with various makes, models, and dealers.  If I discover that three of my friends have recently bought a particular brand that all three have been delighted with, then I might conclude by analogy that if I buy the same brand, I will be delighted too.  Yet it is possible that some models of the same brand of washing machine are sufficiently different that the analogy is misleading.

The Argument from analogy is a special type of inductive argument, whereby perceived similarities between two or more things are used as a basis to infer some further similarity that has yet to be observed.  A typical structure or form of the argument is:

Premise 1: P and Q are similar in respect to properties a, b, and c.

Premise 2: P has been observed to have further property x.

Conclusion: Therefore, Q probably has property x also.

Of course, the premises do not claim that P and Q are identical, only that they are similar.  The argument may provide us with good evidence for the conclusion, but the conclusion does not follow as a matter of logical necessity.  Determining the strength of the argument requires that we take into consideration more than just its form – the content of the premises must also come under scrutiny.  An argument from analogy with insufficient inductive strength is fallacious. This fallacy is related to the Faulty generalisation fallacy.

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Filed under Logical fallacies