Logical Fallacies

I recently found myself in a position where I needed to directly teach logical fallacies to my students, for the first time. As I spent hours researching, preparing materials, and actually teaching classes, I learned quite a few things.

First, they’re difficult. Really difficult. It is easy to present an obvious example of one, and it seems very clear that the logic is bad, but actually trying to figure out whether a real argument is fallacious and how exactly it is… that is not an easy task. I think I’ve lost touch with the difficulty of understanding how these really work because I’ve been studying them for so long and my mind loves logic anyway. To be level appropriate for my students, I’ve needed to modify my thinking about fallacies drastically. Simplify. Clarify. Focus.

Second, they’re everywhere. I mean, I knew they were everywhere, but now I’m realizing just how everywhere they really are. While judging a debate contest recently I counted fallacy after fallacy, non-stop for the entire duration of the event. These students were trying their best to make good, strong arguments, and yet, most of the arguments (and rebuttals) I heard were based in serious logical fallacies I could easily identify. “Straw man” ranked most common, but there were a dozen others that also made multiple appearances.

Third, fallacies sound convincing. In the aforementioned debate contest, I learned from my co-judges: arguments they marked as the strongest were ones I had marked weakest. One judge was entirely persuaded by arguments that were entirely fallacious, and it was a difficult task to explain why a particular argument that sounded fantastic was actually completely vacuous. The student sounded so good, but the entire argument was based on nothing.

Finally, they’re hard to organize and prioritize. While doing my research, I did find useful taxonomies of logical fallacies. However, when I would encounter multitudes of examples I found that fallacies which seemed very different could be quite similar. A “tu quoque” could blend into a “straw man” and a “false dichotomy” all at once in the same statement. Prioritization is always a serious task for a teacher, because we can’t teach everything and must find the things that are most worth teaching in the time we have. Out of the hundreds of fallacies, I had to pick just over a dozen. Though I put hours into the decision of which to include, I still don’t know if I made the right call.

As requested, here is my final list of fallacies:

• Ad Hominem
• Ad Hominem tu Quoque
• Appeal to Nature
• Argument from Authority
• Argument from Ignorance
• Argument from Popularity
• Argument from Tradition
• Begging the Question
• False Dichotomy
• Hasty Generalization
• Non-Sequitur
• No True Scotsman
• Post Hoc Ergo Propter Hoc
• Red Herring
• Slippery Slope
• Straw Man