In this module's material we will describes two phenomena that are both common and useful in the languages that human beings speak, but both of which give rise to the potential for fallacious reasoning. A word or phrase is vague when its meaning is not precise, and it is ambiguous when it has more than one meaning. When we use vague or ambiguous phrases in our reasoning, it is very easy for us to make a number of different kinds of fallacies. This module will teach you what these different kinds of fallacies are, and give us some practice in spotting them, so you can make sure to avoid them in the future. If you want more examples or more detailed discussions of the fallacies that result from vagueness or ambiguity, we recommend Understanding Arguments, Ninth Edition, Chapters 13-14.

This module describes two of the most common fallacies that people make: ad hominem fallacies and appeals to authority. Part of what makes these fallacies so common, and so difficult to avoid, is that many ad hominem arguments, and many appeals to authority, are actually not fallacies at all! Only some of them are. And figuring out which of them are fallacies is more of an art than a science. There is no simple recipe, but there are some rules of thumb you can use. We hope that the practice that you get in this module will help you to improve your skills at distinguish the fallacious from the non-fallacious instances of ad hominem reasoning, as well as appeal to authority. If you want more examples or more detailed discussions of these topics, we recommend Understanding Arguments, Ninth Edition, Chapter 15.

Now we will describe another common set of fallacies: fallacies that occur when an argument makes no progress from its premises to its conclusion. Sometimes, arguments make no progress because the conclusion is already contained in the premises. Sometimes, arguments make no progress because the conclusion is presupposed by the premises. And sometimes, arguments make no progress because the premises don’t make any claim at all, even if they might sound like they do. When you know how to identify such fallacies, you will find that they are more common than you think! If you want more examples or more detailed discussions of these topics, we recommend Understanding Arguments, Ninth Edition, Chapter 16.

This module we will teach you various strategies for refuting a fallacious argument. To refute an argument is to show that the argument is unsuccessful. Even if you are able to identify a fallacious argument as a fallacy, you might still not be able to prove to others that it is a fallacy. In this module, you will learn a variety of techniques for proving to others that the argument is a fallacy. If you want more examples or more detailed discussions of these topics, we recommend Understanding Arguments, Ninth Edition, Chapter 17.

This module gives you time to catch up and review, because we realize that the previous modules include a great deal of challenging material. It will also be provide enough time to take the final quiz as often as you want, with different questions each time. We explain the answers in each exam so that you can learn more and do better when you try the exam again. You may take the quiz as many times as you want in order to learn more and do better, with different questions each time. You will be able to retake the quiz three times every eight hours. You might not need to take more than one version of the exam if you do well enough on your first try. That is up to you. However many versions you take, we hope that all of the exams will provide additional learning experiences.