Here's how to play: Just for grins, let's cover some examples of logical fallacies that we often hear about PowerPoint -- the tool many love to hate. For your Tweeting back channel pleasure, I've also taken the liberty of inventing "Twitter Fallacy Hashtags" you can use when you're listening to a speech, press conference, or presentation. You can either call out the fallacy as the speaker uses them -- or simply Tweet the hashtag with the correct fallacy technique.

The six fallacies I'll cover in this post are:

1. False Analogy

False Analogy Example: "Construction workers use blueprints to guide them as they build. Doctors use X-rays and MRI images as diagnostic aids. Therefore, presenters should use PowerPoint slides as teleprompters during live-audience presentations. "

This argument, of course, is the fallacy of "False Analogy". Why? Blueprints and MRIs are created as visual aids for the construction worker and doctor. A presenter's visual aids are intended for the audience. The comparison, therefore, is invalid.

When a presenter tries to directly connect different situations and goals, they are making a False Analogy. Call them on it, or Tweet #FAnal

2. Post Hoc

Post Hoc Example: "Let's not use PowerPoint for our next presentation. Every time we use PowerPoint, the audience gets bored."


PowerPoint doesn't cause boredom. Not even close. Audience boredom is often caused by bad design, poor storytelling, a monotonous voice, insufferable presentation skills, lack of audience research, or any number of other factors. Those who blame the software tool for boredom are guilty of the fallacy of Post Hoc. In fact, anyone who can't show a clear cause and effect is guilty of Post Hoc and can Tweet #PostHoc. Call them on it.

3. Contradictory Premises

Contradictory Premises Example: "The human brain ignores boring presentations. Therefore, a boring presentation was created by a human without a brain."


This sounds good. Heck, it even sounds right! But when the premises of an argument contradict each other, there can be no argument. If there is an irresistible force, there can be no immovable object. People with functioning brains create boring presentations. And they do so consciously, with rabid attention to boring, minute detail.

Call out "Contradictory Premises" or hashtag "#ConPrem" when you hear an example of this kind of logical fallacy in a speech or presentation.

4. Ad Misericordiam

The Question & Answer portion of a presentation is often a big Ad Misericordiam festival. In Ad Misericordiam, the presenter doesn't answer the question you ask, and instead appeals to your emotions or sympathy. Ad Misericordiam is an extremely popular Q & A technique in business and political press conferences.

Ad Misericordiam Example: Suppose during the Question and Answer period of a presentation, you ask a presenter, "You said our brains ignore boring presentations. If that's true, what about all the subconscious and subliminal stuff our brains capture? Don't our brains really absorb almost everything? Isn't it proven that we can recall boring stuff with incredible accuracy under hypnosis or in our dreams? And why do we talk so much about presentations that bore us? Surely our brains notice -- and even categorize our boredom in painstaking detail!"

The presenter answers, "I put a lot of effort into making my presentation simple and easy to understand for the lay person. You're splitting hairs, muddying the waters, and making it hard for regular people to understand important concepts. I don't deserve this kind of specificity or a bitter, ruthless attack on my scientific integrity."

In the above Q&A example, you'll note that the presenter hasn't really answered your question at all. Instead, the presenter tried to rouse audience pity. The presenter also tried to shame, belittle, or humiliate you for asking rather obvious questions. In this way, the presenter committed the fallacy of Ad Misericordiam. Feel free to shout "Ad Misericordiam" when the presenter doesn't answer the question you asked and appeals to pity instead. Or Tweet Hashtag it with #AdMis

5. Hasty Generalization

Hasty Generalization Example: "I've seen quite a few boring PowerPoint presentations in my day. So have a lot of other people I know. Therefore, all PowerPoint presentations are boring."


In this case, there are far too few examples to reach a conclusion. You've may have seen plenty of bad PowerPoint presentations. But you've also seen some darn interesting ones! So have other people! When a generalization is realized too quickly -- you can shout out, "Hasty Generalization" or tag "#HastyG"

Remember, demanding specificity is the enemy of wacky generalizations!

6. Poisoning the Well

Poisoning the Well Example: Imagine I'm in a debate. My opponent gets up first and says, "Laura is a known fool. She doesn't have a lick of sense, and you cannot believe a word she is going to say."


Of course this isn't fair. I don't stand a chance if I'm called an idiot before I even begin my presentation. The audience is cheated out of the opportunity of finding that out for themselves! My opponent has "poisoned the well" before the audience had an opportunity to drink from it. When you see people "Poisoning the Well" -- call them on it. #PTWell

There are many more fallacies, of course. The six fallacies above are just a few examples about PowerPoint presentations. Fallacies can also be found running rampant in press conferences, media interviews, and current events.

For example, Illinois Governor Rod Blagojevich appears to be a walking, talking fallacy factory lately! For example:

What fallacies do you hear most often? And what lulus have you been hearing in the news or in presentations lately?