Last week we covered logical fallacies and today was no exception. There are so many of them that it really takes a while to go over. Each time I do it I think of a few that I should have left out and a few that I should have included. I suspect I’ll have it correct in about five years.
Today we covered:
Correlation vs. Causation – assuming cause and effect for two things simply because they occurred together
Unexplained vs. Unexplainable – believing that because we cannot explain some phenomenon now, we will never be able to explain it
False continuum – thinking that because no distinct line exists between two extremes, then those two extremes are really the same thing
False dichotomy – insisting that things must either be one way or another
Inconsistency – applying criteria to one thing but not to another
Non-Sequitur – making a conclusion that doesn’t follow from the arguments
Post-hoc ergo propter hoc – saying that because A happened before B, A must have caused B
Reductio ad absurdim – extending an argument to an absurd conclusion
Ad hominem – attacking a person, rather than their claims
Slippery slope – arguing that believing something must also involve believing in its extreme
Special pleading – arbitrarily introducing something into an argument to make it work
It might like a tall order to keep a room full of 12 – 14 year olds interested in this material but I have to tell you, they love it. They were by far the most popular sessions I ran last year and this year seems no different. As soon as I’d mention a different fallacy kids around the room would be raising their kids (or just blurting out) and giving examples they’ve come across.
I’ve found that giving funny examples can really help to both get the point across and keep the kids listening. My favourite correlation/causation example claims that global warming is caused by the decline in piracy. The amount of pirates negatively correlations with global temperatures. Ergo, we need to bring back pirates.
I like to prove to my kids that tall people have bigger vocabularies. My argument goes that small babies have small vocabularies. As they grow taller their vocabularies increase. Ergo, tall people have larger vocabularies.
Examples like this make it perfectly clear what the mistake is. Being able to spot the error in an easy example is a good start to being able to spot more its subtle uses.
Post-hoc ergo propter hoc can be explained by claiming that because a rooster crows before the sun rise, a rooster’s crow causes the sunrise. It’s a variant on the correlation/causation fallacy but from slightly different angle. The two events aren’t happening concurrently, rather sequentially.
My goal now is to put these fallacies into a small booklet for the kids. This will save me from having to go over them several times, hopefully. There are two iPhone apps which I have installed and will give a review of in the next few weeks. I like the idea of my kids running around with logical fallacy databases in their pockets. I don’t know how much nerdier you can get.