Logic Primer 5: Logical Fallacies

Today we will look at logical fallacies. A fallacy is simply an error in thinking. Certain errors are so common they have been classified and named. These are the sorts of fallacies we are dealing with here.

There are two primary categories of fallacies: formal and informal. Formal fallacies have to do with the logical structure of an argument. If the logical structure is incorrect, then the argument has committed a fallacy. Informal fallacies have to do with errors of thinking that happen apart from the structure of an argument. These could include such things as appeals to emotions, personal character attacks, and ambiguous language.

When it comes to informal logic, the tendency for the beginner is to gravitate immediately to the fallacies. Immediate benefit can be gained by understanding where thinking may have gone wrong. However, the student of logic is encouraged to be careful not to label every apparent fallacy they can find. This is not only in many cases impolite, it is not very productive. Recognizing fallacies is only the first step. But bringing proper thinking and clarity to an issue can be the real challange. Every case has its own particular elements, so more information is always helpful to determine the strengths and weaknesses of arguments.

Ideally, when a fallacy is recognized it can be corrected without a sort of “gotcha” attitude. The principle of charity and a gracious manner are essential in seeking common understanding, rather than simply becoming a fallacy-finder.

Because the fallacies cover such a broad range, they are beyond the scope of one post. In addition, many excellent resources can be found on the web for studying the fallacies. Although many good resources are found in print, good audio resources are few. That is why we have provided here an audio podcast adaptation of Stephen’s Guide to Logical Fallacies, one of the well-known fallacy sites on the web. Permission has been granted by logician Stephen Downes. The purpose of the podcast is to introduce and summarize the fallacies and provide examples and solutions to the errors.

You can find the Apologetics 315’s Logical Fallacies podcast on iTunes here. Or use the RSS feed found here. The Logical Fallacies 2nd Edition podcast can be found here.

Stephen’s Guide to Logical Fallacies is found here, with a nice mirror-site with additional content added by Christian philosopher J.P. Moreland at the Illogic Primer here.

The Nizkor Project 42 Fallacies is here.

Audio by Michael Ramsden on Logic and Fallacies can be found here.

Helpful Books:
Nonsense by Robert Gula
Informal Logic by Douglas Walton


Written by

Brian Auten is the founder emeritus of Apologetics315. He is also director of Reasonable Faith Belfast. Brian holds a Masters degree in Christian Apologetics and has interviewed over 150 Christian apologists. His background is in missions, media direction, graphic design, and administration. Brian started Apologetics315 in 2007 to be an apologetics hub to equip Christians to defend the faith.

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