There was a humorous piece in the Sports section of the Guardian recently, written by Harry Pearson and entitled “Super-Sized Stars Need Bringing Down a Leg or Two”. It related to recent complaints that the present generation of golfers are hitting the ball too far.

As golfers have grown bigger and stronger, holes that used to be challenging par 5s have been getting easier. Golfers used to struggle to reach the greens of such holes in 3 shots; now, all too often, they can comfortably get there in two. Par 4 holes, too, no longer present the difficulties that they were designed to. For those at the top of the sport, golf has become too easy.

The author of the article proposed a solution to this problem: hack the legs off golfers. This would limit their ablity to send the ball soaring over the horizon, restoring the challenge of the game. Of course, he proposed this solution tongue-in-cheek, but the argument that he offered for it nicely illustrated a logical fallacy. It went like this:

“Golfers have quite literally outgrown their sport. The solution is either to make the courses bigger–something that is practically impossible since, as far as I can judge, they already cover 80% of the world’s non-urban landmass–or make the golfers smaller. There would be a number of ways of achieving the latter, but clearly the cheapest, quickest and, to those of us with a marked antipathy to the game, most cheerful way would simply be to cut off their legs with a chainsaw. Some readers will feel this is cruel and inhumane, but experts assure me that so long as it was blindfolded before tackling Ian Poulter the chainsaw would suffer no lasting trauma.”

The implied conclusion here–that we should take a chainsaw to golfers’ knees–is arrived at by restricting the options. According to Harry Pearson, we must choose between two options: making golf courses larger or making golfers smaller. As the former solution is impractical, we are forced to adopt the latter.

This, of course, ignores a number of other solutions, some of which are alluded to elsewhere in the article: we could make golf balls heavier or less aerodynamic; we could change the heads or shafts of golf clubs to make them less efficient; we could get rid of tees for driving. Without considering and eliminating these alternatives, the argument (thankfully, from the golfers’ perspective) can’t establish its conclusion.

A nice illustration of a fallacy from The Simpsons:

After a single bear wandering into town has drawn an over-reaction from the residents of Springfield, Homer stands outside his house and muses, “Not a bear in sight. The Bear Patrol is working like a charm!”

Lisa sees through his reasoning: “That’s specious reasoning, dad.” Homer, misunderstanding the word “specious”, thanks her for the compliment.

Optimistically, she tries to explain the error in his argument: “By your logic, I could claim that this rock keeps tigers away.” Homer is confused: “Hmm; how does it work?” Lisa: “It doesn’t work; it’s just a stupid rock!” Homer: “Uh-huh.” Lisa: “… but I don’t see any tigers around, do you?”

Homer, after a moment’s thought: “Lisa, I want to buy your rock…”

Correlation does not imply causation. Just because two things occur together, does not mean that one caused the other. Homer argues that as the Bear Patrol vans are correlated with an absence of bears, the former must have caused the latter. Lisa, tongue in cheek, argues that as the presence of her rock is correlated with an absence of tigers, the former must have caused the latter.

At least Homer recognises that the two arguments are on a par, even if he fails to recognise that both are examples of the correlation not causation fallacy.

Critical Thinking is a practical subject; learning the theory is one thing, but to really get to grips with the course you should be applying it.

We are constantly being bombarded with evidence and arguments, so opportunities to do this shouldn’t be hard to find. Listen to the radio, watch the news, read a newspaper; you’ll soon be confronted with something relevant to the course.

This blog is somewhere for me to post examples that I see. Suggestions by email for further examples are very welcome.