How to Think: An Introduction to Logic
My online course on logic at the Mises Academy has one main emphasis: how to analyze arguments, especially arguments about philosophy, politics, and economics. I've found that many, if not most, writers on these subjects fall victim to common fallacies. Once you are aware of these fallacies, you will find them easy to avoid in your own arguments — or at least easier to avoid than if you weren't aware of them.
One example is begging the question, i.e., assuming what you are supposed to be proving. As an example, one influential philosophical movement — you'll find out which one if you take the course — offers an elaborate account of how we obtain concepts through abstraction. So far as I can see, though, the supporters of the view in question don't give any arguments at all that we do get our concepts in this way: they just describe their theory and act as if they have shown it to be true.
Another example came up recently in a book that favored democracy in the workplace. The author claimed that other types of management failed the "golden-rule test": if you were an employee of a firm where you weren't given a say in management, you would think this was unfair. Therefore, you should support democratic management for all firms. Of course the problem here is that the author can't just assume that you would think your not getting a say in management is unfair — that's what he is supposed to be trying to prove.
Another frequent fallacy is the persuasive definition, in which a partisan meaning is incorporated into the definition of a term in common use. People who favor equal distribution of wealth often define a just society so that it must incorporate the sort of equality they think appropriate. Then, if you reject equality, you will be rejecting justice — but only because the term has been defined to ensure the desired conclusion.
We will discuss a number of other common fallacies, and by the end of the course, you should be able to diagnose the mistakes of most of the arguments you encounter. The course emphasizes class participation: you are encouraged to send in arguments that you would like analyzed. If you do, I'll go over them with the class.
Besides analyzing fallacies, we will go over the essentials of logical theory. Our text is Principles of Logic by George H. Joyce.
This is one of the best presentations of the old Scholastic logic. Among the topics that the book covers are concepts and judgments, the laws of thought, and syllogistic reasoning. Besides going through Joyce's book, I'll also discuss the areas in which modern mathematical logic differs from the Scholastic logic that Joyce presents. Rest assured, though: we won't be dealing with overly technical or difficult material.
One of the strengths of Joyce's book is its detailed account of inductive reasoning and scientific method. I'll compare what Joyce says with other views, such as the inductive skepticism of Karl Popper. Leonard Peikoff claims to have made a revolutionary advance in the theory of induction, and we'll try to determine whether his claims have merit.