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Logical Fallacies (2): 5 MORE abuses of logic

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Here are 5 more 'logical fallacies', i.e. seemingly logical arguments in support of something that aren't really logical at all (see my previous article Using and abusing logic: 7 logical fallacies). If you want to see them all used on an almost daily basis, browse the readers' comments at the end of articles published in any newspaper (on either side of the Atlantic).

8. Populism

This is the claim that something must be right or true because a lot of people believe it to be so. Now this of course is not always a fallacy - it can be true. For example, I was trying to teach my nephew table manners recently and he couldn't see why he couldn't eat how he wanted to. My argument was "They're the rules, that's all; you don't have to understand why, you just have to follow them." Not the finest use of incisive logic I agree, but the reality is that if enough people agree that something constitutes good manners or politeness, then in that society or community, that is the standard for manners.

However ...... it's not necessarily true. For example:

"We really need to invest heavily in a social media strategy. All the available data shows that companies are switching from traditional media to advertising on Facebook and other social media sites."
"Is there any evidence that investing on these sites is cost effective and produces a return?"
"No, but companies wouldn't be rushing to do it in their thousands unless it worked."

If you find yourself faced with an argument like this, say something like, "In the Middle Ages most people believed the world was flat, the sun revolved around the earth and that blood letting with leeches could cure most ailments. That didn't make any of them true."

9. New Is Better (Argumentum ad novitatem)

The opposite of Argumentum ad antiquitam, this the argument that something is better or correct simply because it's new. There is a strong appeal to this 'logic' because we tend to believe that progress means that new things are always better than the old.

"We really need to invest heavily in a social media strategy. All the available data shows that companies are switching from traditional media to advertising on Facebook and other social media sites."
"But our old marketing strategy has always worked very well. I don't just want to jump on a social media bandwaggon."
"We need to stay at the cutting edge, and that means being early adaptors of new techniques. Social media is the latest thing, so it will obviously work better than the traditional methods."

"There's a new attitude to gay marriage nowadays, especially among the young. People aren't shackled with outdated notions of morality any more."
"What about the deeply held views of millions of more traditional people?"
"Just as the dinosaurs died off to make way for humans, old attitudes have to give way to new ones. And just as humans are superior to dinosaurs, new, modern attitudes are superior to old ones."

10. Personal Attack (Ad Hominem Abusive)

This is basically a personal attack (the Latin ad hominem meaning 'against the person') where a proposal is rejected on the basis of some fact about the person making the argument. It can be valid, of course, but just because someone's been wrong about something or made a mistake in the past doesn't mean their point of view is invalid THIS time.

"Jack is criticizing this investment as being being unaffordable. Need I remind you, this is the man who overspent on project X by almost $100,000 last year!"

"I really believe that course of action is wrong."
"Of course you'd say that, you're a Republican/Democrat."

"That's irrelevant; what about the argument I've put forward?"
"It doesn't count. You have to say that."

"Ben says we need to reduce the price on brand X by 10%."
"Well he would say that, he's a sales guy. You know what Sales are like. They want to give everything away."

"The Chairman of the JSC has asked for an increase in military spending."
"You know what these military guys are like. When have they ever said they DON'T need more?"

"Obama suggests the UK should stay in the EU. Is this the same Obama who had hardly been outside the US before he campaigned for President? Hardly the best person to comment on foreign affiars."

Often the criticism is aimed at a country/institution/organization/competitor instead of an individual:

"China has very strict gun control and their number of gun-related deaths each year is tiny. We should follow their example."
"Yes, that's a great idea. Let's take lessons from that shining example of democracy the People's republic of China!"

"The UK Defence Minister has proposed pooling resources with our European allies."
"What a great idea; let's rely on the French for our defence. But remind me first ... when was the last time they won a war?"

"We should take competitor X's example on this and follow suit."
"Is this the same competitor X that launched the unsuccessful XYZ last year? Great idea."

"The NRA says a ban on assault weapons won't do anything to address the problem, but when has the NRA backed ANY gun control suggestions?"

If you're ever 'attacked' with the accusation that you're now saying the opposite of something you've said in the past, use the quote normally attributed to economist John Maynard Keynes (though you could just as easily attribute it to Abraham Lincoln, who can do no wrong at the moment) and say, "John Maynard Keynes was once accused of changing his position on an issue and he said, 'When the facts change, I change my mind. What do you do?' ...... I'd say the same thing.' "

11. Vividness

This is where one dramatic event or a small number of them are used to outweigh a significant amount of statistical data. In business presentations, an anecdote about a single event can often have far greater weight than a plethora of facts.

In one behavioral science experiment (T Wilson, Psychological Bulletin 1994) a group of college students were asked to compare the merits of two brands of condom. They were given a consumer magazine style article which objectively compared the two brands across a variety of measures and overwhelmingly favored Brand A, and some first-hand dramatic anecdotal evidence that favored Brand B (e.g. a story from a female student who told of the time Brand A burst during use and she became pregnant).

97% of the students (that’s as near to unanimity as you’re ever going to get in an experiment like this!) agreed that the article was the most reliable and objective source of information. But then the real point of the experiment took place. When they were leaving, the students were told they could take some samples with them.  31% took samples of Brand B.

In other words, even when the stories totally contradicted the facts, almost one-third of people STILL went with the stories, which shows how powerful anecdotes about dramatic events can be.

But of course the fact that something is dramatic or vivid doesn't make it any more relevant.

Opponents of gun control would accuse supporters of new legislation of doing this when they use the Sandy Hook tragedy as proof that automatic weapons should be banned. And they'd be correct. Either automatic weapons should be banned or they shouldn't. But one single event - no matter how tragic and appalling - doesn't clinch the argument for banning them.

12. Slippery Slope

This argues that something will automatically follow from something else without presenting any argument in support of it:

"Banning automatic weapons and high-capacity magazines will just be the first step. The next thing will be a total ban on all firearms."

"Legalizing marijuana is the first step on a very slippery slope indeed. What's next - selling heroin over the counter at Wal Mart?

"Reducing the price by 10%? Why don't we just give the stuff away and be done with it?"

"I need the approval to spend $250,000 because we have to kill off competitor X's new product right away. If we don't, mark my words ...... we'll turn around in 12 months time and discover they've got 25% market share."

"If we extend the product returns policy to 12 months, next thing you know we'll have thousands of customers bringing stuff back that's a year old that we can't sell to anyone else."

"The collapse of the euro/Brexit could lead to war."



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