Monthly Archives: May 2012

Logical fallacies part trois

Finished! Finally!

Got through the list of the last few fallacies:

Straw man – creating a false argument to argue against (because it is easier)

Tautology – Claiming that A = B because A = B

Moving the goalpost – Losing an argument, then changing the focus of the argument

Tu quoque – attacking a person because they are guilty of what they are arguing against

Begging the question – Leaving out an important assumption that your argument makes

Again, the kids really enjoyed going through them all and even came up with some great ideas. When I mentioned to them that “millions of people use acupuncture” is an argument from popularity, one student said “what about the millions who don’t use it? Surely less than half the world uses acupuncture!”

I had never thought about it this way. If as many as 1 billion people around the world use acupuncture, then 6 billion people don’t use it! As a maths teacher I feel confident in stating that 6,000,000,000 > 1,000,000,000. Therefore, by that logical fallacy acupuncture must not work.

This is one of the great things about teaching, being taught things by your kids.

Some of them also pointed that labelling people can become an ad hominem attack. We have a homeopath coming to visit and it was mentioned that if we are debating any of his point, we cannot dismiss them simply because of what he does. Every argument needs to be refuted on its own merits. Even labelling somebody a sceptic can be counter-productive. It’s a label I apply to myself but I wouldn’t want somebody dismissing me simply from hearing that. If I am a sceptic then I must be unimaginative and contrary. (Sometimes I am but that’s beside the point)

We closed our session today with a logical fallacy quiz! One of my senior girls put together some quotes that the rest of the kids had to de-fallacise. I will get a copy from her later during the week and put it together for you all to peruse.


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Victorian Humanist Society talk

Last night I had a wonderful time speaking for the Victorian Humanist Society. There were a couple of AV issues so I wasn’t able to use the PowerPoint presentation I had prepared but I think I winged it pretty well.

Some really interesting (and tough!) questions were asked and hopefully answered well. It was also great meeting a few more members of the Vic Skeptics and chatting with them. I hope they won’t be too bored when they hear me give the same talk for the Mordi Skeptics, Vic Skeptics and at the national convention…

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No meeting today

Sorry folks, I had to take a sickie today my poor SceptiKids were left to fend for themselves. I like to imagine them  wandering the school yard forlornly, occasionally bumping into one another and shaking their heads sadly.

If you haven’t already, why not take a read of the original article that started this whole crazy thang.

I started a high school sceptical society, here’s how it went…

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Why I love what I do

One of my SceptiKids showed me a picture on her phone today:

She’d watched a YouTube video of Michael Shermer debunking James Van Praagh and risked her sanity by reading through the comments. The above comment was worthy of a screen grab, she decided. I asked her to email it to me and she did, along with this comment:

I watched some other videos with James Van Praagh as well. I tried to do what you taught us – keep a tally of how many times he scored and how many times he missed. The misses outnumbered the hits by far, as expected… also, I noticed that most if not all of the hits were general statements, such as “your mother suffered from back problems” or something along those lines. Some of the audience were convinced and shocked everytime he scored but you could tell there were some people who were quite sceptical. Very interesting to watch!!

This is why I love being in a position where I can teach kids about scepticism. This is the quality of the kids we have today. Not just at my school, but at every school. We need to reach more children like this and show them how to think critically and sceptically. How to question and how to look for answers. These are the people who will be running the planet when we’re old and this is one of the kids I’d trust to do it.

But you know what part impresses me the most?

She’s only 13.

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Marriage equality and scepticism

We were supposed to continue discussing logical fallacies today but the topic of marriage equality came up very early in. Quite a few staff and students attended last Saturday’s rally so the topic was fairly hot on people’s minds.

It can be risky for teachers to discuss topics like this with students given how emotive they are. It’s very difficult to create an atmosphere where students feel safe sharing their (potentially unpopular) opinions and also avoiding any element of ‘religion bashing’. Obviously there is a very strong religious component to this debate so you have to be careful.

What I did feel safe talking about was the marriage equality issue from the sceptical viewpoint. Can we ignore our personal feelings and upbringings and examine both sides from a purely empirical stance?

The argument against marriage equality that interested the students the most was the claim that children raised in “non-traditional” marriages will suffer psychologically. My students didn’t appear to like this claim overly much. One had a friend who was raised by two mothers and two fathers and is apparently quite a well-adjusted young lad. Another student mentioned that some people don’t think that single people should be allowed to raise children and asked what happens to widows and widowers? Do they have to hand over their child after losing a partner?

One student wanted to know if this argument could be extended to any non “nuclear” families. If a mother and a father have five children, is that damaging to the kids? What about only children?

Ultimately it all came down the evidence. Is there evidence showing that same-sex raised children suffer psychologically? Short answer, no.

Some people disagree with this, but I mentioned that if there was compelling evidence against same-sex marriage the sceptical community would probably be against it as well. Our duty if you will is to follow the evidence despite how unpopular this makes us.

Fortunately this isn’t the case here.

The idea of “traditional marriage” was also raised. Yes, a traditional marriage today is between a man and a woman, but don’t traditions change over time? A while ago a traditional marriage meant a woman married to her dead husband’s brother. Or a man married to his slaves. Those traditions changed so my kids weren’t too sure why they couldn’t change again.

The biggest point raised by a student was how important it is for us to understand everybody’s point of view. This student didn’t believe it was necessarily a religious debate but more an idealistic one. There are a lot of people who firmly believe that their way of life is the best one available. They were raised a certain way and they turned out fine so therefore everybody else should be the same. A great discussion followed about how hard it is to accept the fact that what’s right for you isn’t right for everybody.

It’s really touching to see how many students would rather see things from another’s point of view than simply argue with them. Now I’ve seen these kids argue and they are formidable but they also know when a softer touch is better.

Next week we may continue our discussion or we may move on. I really wanted to share this session with you all though because of how proud it made me. It wasn’t the side taken by the students that impressed me but more the way the argued their cases. With the exception of two of them they were all 14 years old and younger. One day I’ll stop being amazed at how deep these kids are but I hope that doesn’t happen soon.

McKinnon staff/students at the marriage equality rally


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Why I am attending the marriage equality rally this Saturday

All of my friends are straight.

All of my family is straight.

I am straight and so is my wife.

Allowing gay people to marry will have absolutely no affect on my life.

But imagine what the world would be like if people only stood up for themselves.

I don’t believe any of this “homosexuality is a choice” crap.

I especially don’t believe that allowing same-sex marriage will lead to people marrying animals, objects and children.

I don’t care what the Bible says about it because not everybody follows the Bible.

I don’t care if homosexuality makes you uncomfortable, that’s your problem, not theirs.

If you feel that marriage equality will threaten your marriage then maybe you need to look at your own relationship.

On Saturday the 12th of May I will be attending the marriage equality rally at the State Library of Victoria along with many other teachers and students from my school. Despite the zero affect this issue will have on my life, it will have major affects on the lives of others. I don’t want to be the type of person who only looks out for themselves.

I am a straight man and I support gay marriage.

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More logical fallacies

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

Fatty fat fat!

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.

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