Logical Fallacies (I)

Enter ... the slippery slope. (The Bus 3.1)

Welcome aboard The Bus!

The Stop

Logical fallacies are arguments built on false reasoning. Initially, they might appear true - and can be persuasive. Consequently, they are often used in rhetoric to encourage people to think a certain way or believe certain things, and - as they usually appeal to emotions - are often very effective. However, fallacious arguments are built on flawed reasoning that is exposed when logic is applied. There are many types of logical fallacies, and philosophers as far back as Aristotle have recognised the need to detect and avoid them to be essential. Take, for example, the slippery slope.¹

Photo by marianne bos on Unsplash

The slippery slope fallacy works rhetorically because its false logic plays on emotion, particularly the fear that a small allowance will lead inevitably to the worst outcome.² Based on the assumption that ‘one event will lead to a specific outcome, or that two distinct events must be handled the same way because of an overlapping characteristic, regardless of [any] data to support this claim,’ the fallacy occurs in either stages - where each ‘step’ on the slope (a to z) is justified by its predecessor (if a then b, if b then c, etc.) - or directly - where the outcome runs straight down the slope (a to z) without any ‘middle steps.’

The fallacious nature of the slippery slope argument can be seen in this analogy:

1. If someone is selling a used car for £1000 and you offer them £999, it is likely they would accept the offer.

2. If might then follow that, if they’re willing to accept £999, there’s no reason they shouldn’t accept £998 as there’s no real difference between the two.

3. Similarly, there’s also no real difference between £998 and £997 - or £996 and £995, or £994 and £993, etc.

4. Therefore, in the logic of the slippery-slope argument, it might be argued the car might as well be given away for free.

Responding to this fallacy requires us to judge the point at which the inference (in this case, the minimum price) becomes unacceptable. Failing to reach this judgement leaves us vulnerable to ‘sliding’ all the way down the slope and accepting a position which in truth we ought not to accept.

Here’s another example:

1. If you don’t do your homework, you’ll fail this course.

2. Fail this course and you’ll flunk out of college.

3. Flunk out of college and you won’t get a job.

4. No job means no money.

5. No money means no house.

6. No house means you’ll wind up sleeping drunk on a park bench and you’ll be dead before you’re thirty.

In this example, logic points out that in no way is step 6 an inevitable result from step 1 - and, of course, step 1 isn’t inevitable, either. It’s perfectly possible to pass a course without doing the homework - I’ve had plenty of pupils who have proven that point. Of course, they may not have passed with a decent grade (though naturally, some did - we all know that type of kid), but they didn’t necessarily flunk.

Unfortunately, serious decisions are often allowed to be made when people are persuaded by slippery slope arguments that deliberately whip up social, political or cultural fears. For example:

• ‘Legalising euthanasia will result in home euthanasia kits being sold over the counter at Walgreens. Thus, we should not legalise euthanasia.’

• ‘Teaching teenagers about birth control gives them a license to have sex. Thus, we should not teach teenagers about birth control.’

• ‘Outlawing fully-automatic weapons will lead to laws against all weapons, and then we will begin restricting other rights, and finally we will end up living in a Communist state. Thus, we should not ban fully-automatic weapons.’

In all three, the ‘worst-case’ outcome - which does not logically follow from the premise - plays on certain fears, and thus for many people the arguments appear sound. However, logically they are not: legalising euthanasia will not automatically lead to my being able to stop off and pick up a DIY suicide kit at my local pharmacy on the way home after a tough day at work; it is a fundamental fact that countless teenagers are going to have sex with or without instruction on birth control (and it’s better that they’re informed about this than not );³ and in no way will a ban on fully-automatic weapons necessarily usher in a Communist state.

The Detour

Today’s Detour is to Earthling - an animated documentary (10:17) about Jack Weiner, who claims that - during a camping trip in Maine’s Allagash wilderness in the summer of 1976 - he, his twin brother Jim, and two friends were abducted by aliens. Ten years later - following ‘massive changes in their their personalities, changes brought on by repressed memories’ - the four explored their experience through hypnosis. True or not, there’s a good lesson for humanity near the end of this. Plus, it’s a really cool video.

Earthling

The Recommendation

Today’s Recommendation is Mark Miodownik’s⁴ Liquid: The Delightful and Dangerous Substances That Flow Through Our Lives (2018) - a fascinating and very readable investigation into everyday liquids that surround us. I guarantee you’ll never look at liquids (or solids, for that matter) the same way again.

From the inside cover: A series of glasses of transparent liquids is in front of you: but which will quench your thirst and which will kill you? And why? Why does one make us drunk, and another power a jumbo jet?

This fascinating new book by the bestselling scientist and engineer Mark Miodownik is an expert tour of the world of the droplets, heartbeats and ocean waves that we come across every day. Structured around a plane journey which sees encounters with substances from water and glue to coffee and wine, he shows how these liquids can bring death and destruction as well as wonder and fascination.

From László Bíró’s revolutionary pen and Abraham Gesner’s kerosene to cutting-edge research on self-repairing roads and liquid computers, Miodownik uses his winning formula of scientific storytelling to bring the everyday to life. He reveals why liquids can flow up a hill but down a hill, why oil is sticky, how waves can travel so far, and how to make the perfect cup of tea.

Here are the secret lives of substances that we rely on but rarely understand.

Remember: You can always buy Liquid from Amazon, but you can also get it from your local new or used bookstores - or even check it out from the library. And those options are better for everyone.

The Sounds

Today’s playlist - which I intended to be based around the Stop - started off well enough with ‘The Logical Song’ (Supertramp, 1979), but - as I couldn’t find any other decent songs about ‘logic’ - is followed by four other great tracks from that year: ‘Tragedy’ (Bee Gees, 1979), ‘Dance the Night Away’ (Van Halen, 1979), ‘Life During Wartime’ (Talking Heads, 1979) and ‘Highway to Hell’ (AC/DC, 1979). Enjoy!

The Thought

Today’s Thought is from Alan Watts, an influential British philosopher and writer known for his prolific output and ability to ‘translate’ Eastern philosophical ideas into a Western mindset:⁵

‘No amount of anxiety makes any difference to anything that is going to happen.’

If you have a thought on this Thought - or any part of today’s issue - please leave a comment below:

And that’s the end of this Stop - I hope you enjoyed the diversion!

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Until the next Stop …

1. I’ve enjoyed teaching how to spot fallacies for years - and the slippery slope is one of my favourites because it’s so easy to spot, and yet it’s used all the time as if it’s legitimate. Sources for today’s Stop include Fallacy (Britannica), Fallacies (Stanford), and random class notes from ones I taught years ago.

2. The ‘give them enough rope, they’ll hang themselves’ idea.

3. I've never seen this fallacy used more than when I was - for a short time - the only teacher representative on my local school council’s Sexual Health Advisory Committee. This was in the heyday of the GW Bush administration’s push on ‘abstinence-only sex education,’ and - with the exception of one other member (who, as one of the school system’s administrators, was the only other educator) - everyone was a parent or ‘concerned citizen’ of the book-burning, shun-those-who-are-different brigade. In other words, people for whom ‘slippery slope’ equals perfect logic. The meetings were an exercise in tedious futility and I have few memories, except for one. There was a particularly vile person who had made her mind up on the issue long before she’d used her business connections to wrangle her way onto the committee. During a particularly heated exchange, she was pressed by the administrator about why she thought teenagers didn’t need to learn about contraception. She looked him in the eye and replied (and I mostly quote/somewhat paraphrase): ‘If you teach teenagers about birth control, they’ll start having sex. And if they start having sex, then they’ll have babies. And if they start having babies, they won’t be able to have jobs. And if they don’t have jobs, they can’t pay taxes. So, no. Teenagers don’t need to be told anything about sex except not to do it because teenagers will do what they’re told.’ Even now, my first reaction is to say ‘wow,’ and slam my forehead to the table. Obviously, you could point out the slippery slope fallacy being played here, but that ignores the begged question as to how teaching contraception leads to pregnancy - as contraception prevents pregnancy. It’s also ignoring the fact that teenagers don’t do what they’re told - a fact lost on this woman, who’s own daughter got pregnant when she was in high school. Which, as an argument against her stance is an ad hominem fallacy, but 30 years on I still think she deserves being called out on it.

4. Miodownik is the University College London Professor of Materials and Society, and champions ‘materials science research that links to the arts and humanities, medicine, and society.’ For more information, see: Mark Miodownik.

5. For more information about him, see: Alan Watts.