Introduction

This lesson focuses on learning to spot logical fallacies in arguments. It will make you wiser, wealthier, happier, healthier, savvier and safer. Yes, really.

You may have used fallacious reasoning by trying to convince your parents or teachers to allow you to do something or to buy your excuses: “Why can’t I go to the party? Everyone else is!” or “You should accept this late essay and not count off any points because I am a nice person.” However, if you get caught doing this too often, you will lose credibility, and any future efforts at persuasion will be much harder.

All around us people try to manipulate us with invalid or illogical proof, insufficient choices, or conclusions that don’t follow from the proof. Advertisers and salespeople convince us to buy things we really don’t need. Politicians and diet books make promises they can’t keep. Photographers publish pictures that tell only part of the story. Parents make children obey “because we say so.” People use fallacies because they work. Fallacies are tricks of logic that often appear reasonable when in fact they are nothing more than means of manipulation—means that work all too often. All of us need to acquire skills to protect ourselves from falling victim to such tricks of logic. By learning to detect fallacies, you can protect your values, your self-image, and your buying habits.

The exercises below should give you the resources to defend yourself against the onslaught of persuasive messages you receive every day. Some people compare the knowledge you will gain to ammunition or martial arts. It’s like a war out there, so be prepared.