Know Your Logical Fallacies

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poster of logical fallacies with a short description of each and a picture of the Greek philosophers

Click on image for higher res version – please see the site for instructions on how to print a readable version

Ever found yourself reacting with disbelief – rage, even – to any kind of public debate where there are massive holes in the logic of the arguments?

Even more maddening is when these holes are not pointed out by anyone who is moderating, or others participating, and the debate proceeds based on a flawed basis.

The field of sustainability is no exception – watched a debate on climate change or the carbon tax lately? If we could improve the quality of debate on sustainability issues, and public issues in general, we could cut out all the superfluous, time-wasting diversions faulty logic enables, and get to the core of what we need to resolve.

In previous posts I’ve discussed how logic and rational appeal won’t necessarily change someone’s views on an issue – but where logic is used, it’s important to be able to spot when someone is using a dodgy basis for making a point, and be able to call them out on it.

It’s also crucial that you become aware of any fallacies you yourself may commit, so you can purge them from your communication repertoire!

But how do would-be fallacy-spotters, with little training in rhetoric and reasoning, know what to look for?

Luckily, Jesse Richardson, Andy Smith and Som Meaden have created thou shalt not commit logical fallacies, a clever, well designed and useful site that has condensed the wisdom of Plato, Socrates, Aristotle (and others) into a bite-size form, using easy to understand language.

The trio describe a logical fallacy as:

…usually what has happened when someone is wrong about something. It’s a flaw in reasoning. They’re like tricks or illusions of thought, and they’re often very sneakily used by politicians and the media to fool people.

The creators have developed icons to represent each of the 24 identified fallacies, which include ad-hominem – attacking your opponent’s personality traits or character instead of engaging with the issue; and strawman – misrepresenting your opponent’s argument to make it easier to attack.

screenshot of strawman logical fallacy

Mousing over each icon gives a one sentence summary of the fallacy, and clicking the relevant icon links to a short description and example.

In a fun twist, the site suggests that if a logical fallacy is spotted, the link to the relevant fallacy from the site be forwarded to the fallacy-committer, or included in a comment or response to them!

Even more entertaining would be if the site could also collect and publish fallacies submitted by people who spot them – like a crowdsourced rogues’ gallery of logic-underminers.

The site is a useful teaching tool for sharpening critical thinking and debating skills. It is a simple idea, but it serves an important function – it allows this knowledge to be quickly accessible without needing to have studied the Greek philosophers, and it supports a healthy democratic process. The quality of much of what passes for ‘debate’ in the public domain can only improve with a citizenry well-equipped to spot a strawman or a tu quoque.

A free pdf poster of the fallacies can be downloaded from the site. The creators have made this resource available for free – so please consider tipping them a few bucks using the Donate button on the site.

Do you recall a time when you were watching a debate, or when someone with whom you were having a debate came out with a lapse in logic that left you incredulous, or in fits of laughter?

Have you ever caught yourself using any of the identified fallacies? Which ones? 

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  1. You know, I have all of this in neat little folders, but that is a terrific, visual way of presenting the information quickly! Very very useful.

    What a shame there’s so little evidence of any of it being used :)


  2. hey Sharon,

    Thanks so much for the plug, and thanks also for practicing what you preach in adding to our beer fund!


    • You’re welcome! I got an email from a friend of mine in the States about this post who said that he’d been looking for a poster like this for about ten years, and was forwarding it on to his (extensive) networks, so it will get a bit more airplay from this post. Cheers!


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