It is easy to lie with science and even sound erudite and sometimes even get paid to do it. Even well-respected writers like George Will do it all the time. The way it’s done is through little argumentative sleights of hand known as logical fallacies. Logical fallacies are errors in reasoning. Sometimes they are made unwittingly, sometimes they just appear out of lazy argumentation or lazy writing, but mostly they are deliberately employed to manipulate opinion. One of the most important things anyone can learn is how to identify logical fallacies in any argument. Having this skill is like having a built in “bullshit detector” at your disposal, ready for use at cocktail parties, lectures, watching cable news, or reading the Sunday paper. Logical fallacies are made by persons on the left, right and center of the political spectrum. Sometimes they can be legitimate rhetorical devices–especially in political speeches–but being able to identify them is the first step in determining if the argument behind them is legitimate.
For a mostly graphical way to introduce the most common logical fallacies, download my Field Guide to Logical Fallacies slide show, which contains simple figures like this:
The Ad Hominem fallacy is when someone tries to discredit an argument by discrediting the person who made the argument. Just because the person who made the argument has some unsavory characteristics does not necessarily mean that the argument is flawed.
The Guilt by Association fallacy is when someone points out that undesirable people also made a similar argument. In this case, the fallacious speaker is noting that Nazis made similar arguments to the speaker. If the original argument was indeed something like, “Jews are an inferior race,” it may be legitimate to note that Nazis made a similar argument, but if the original argument was something like, “a strong scientific education will lead to a prosperous nation,” then noting that Nazis also made such an argument is not really relevant.
The Red Herring fallacy is when something alarming is held up as a counter, or alternative, to the original argument, without presenting any justification of how the two are related.
Please download the Field Guide to Logical Fallacies to see more. Feel free to use the slides in your classes or however else you see fit, just let me know if you do.
A great exercise in field identification is then to find an opinion piece from a newspaper or website and try to identify all the logical fallacies the author makes. For example, this piece on climate change by George Will (Please George, stick to baseball!) contains at least nine big fallacies—not bad for a 740 word essay! However, George Will is a rank amateur at using fallacies compared to other news makers–this op-ed on climate change by Sarah Palin contains at least 33 fallacies in 762 words, you betcha!
For a more detailed treatment of fallacies, there are many websites that list and describe a large number of logical fallacies. My favorite is: http://www.nizkor.org/features/fallacies/.