• Attacking the straw person
Another common fallacy occurs in counterarguments – that of attacking a straw person. The counterarguer commits the straw person fallacy if she argues against a claim that was not asserted in or implied by the original argument. While the counterargument might well be effective against that claim, if the claim was not made in the original argument, the counterargument attacks an imaginary opponent – a straw person rather than a real person. For example:
David: You ought to be very careful if you encounter a funnel web spider, because they are highly venomous and aggressive.
Pauline: Spiders are not dangerous! My friend has a pet tarantula, and it is really gentle.
Pauline puts forward a good argument against the generalisation "All spiders are dangerous", but that was not a claim made by David, nor a claim implied by his argument. Pauline has not given us any reason to think that funnel webs are not aggressive and dangerous. David’s response should be "But I didn’t say that!"
Note that, if there is a contentious suppressed premise in the original argument, it is good for the counterarguer to attack that premise. In such a case it might look as if the counterarguer is committing a straw person fallacy, because she attacks a claim that was not made explicitly in the original argument. But since the claim was implicit in the original argument, it is an appropriate target. e.g. The abortion example above. No straw person fallacy has been committed. For example:
Paul: Our ancestors, the white invaders, were responsible for many Aboriginal deaths. Therefore current white Australians should apologise to Aborigines.
John: As Paul notes, the white invaders are not literally the same people as current white Australians – they are our ancestors. Yet it is inappropriate to apologise for actions that we ourselves did not perform.
John's response is not a straw person fallacy, because, even though Paul did not state it explicitly, his argument does contain the suppressed premise that current white Australians are related to white invaders in such a way that it is appropriate for us to apologise for their actions. Paul's response should not be "But I didn't say that!", because in fact his argument implied it. Paul’s response should be "Here's why it is appropriate to bear responsibility for the actions of our ancestors..."
When and why do straw person fallacies occur? Often, straw person fallacies occur when the counterargument exaggerates the claims made in the original argument. You see this routinely in political exchanges, and in letters pages of newspapers. For example:
Letter 1: Tourists should be warned against swimming at Australian ocean beaches, because they are at high risk of drowning.
Letter 2: If you prohibit tourists from swimming, they won’t come here anymore. There goes the economy.
Note that letter 1 did not claim that tourists should be prohibited from swimming everywhere in Australia, just warned against swimming at ocean beaches. Why did the writer of letter 2 fall into the mistake of a straw person fallacy? Because by exaggerating your opponents claims, they are easier to dismiss. Thus, straw person fallacies often occur in disputes in which people have deeply entrenched opinions, where people have already made up their minds, and are unwilling to give serious consideration to alternative views.