Comic strips are a great place to find examples of informal fallacies. It seems that we tend to find improper reasoning funny. In the “Peanuts” comic strip, Lucy is ad baculum incarnate. Below is the entire strip:
Note that the fallacy is not really made by Lucy making the threat, but by Charlie Brown, who is convinced by her “argument.”
Here is another example, where Lucy persuades Linus to memorize his lines using “five good reasons”:
Here is an example of Calvin falling for his father’s ipse dixit :
For the ad populum, consider this classic bandwagon example from “Zits”:
There are many more examples of informal fallacies in the funnies. See what you can find!
Would you like to be a fly on the wall in my logic class? Want to improve your understanding and/or teaching of logic by watching me teach and interact with my students, discussing the lesson after the class, and having the recorded class sessions available? If so, click HEREto audit Intermediate Logic for the 2017 school year!
What’s included for Auditors? First, you have access to all the live classes. During the discussion, you will not be called upon as I do with my regular students. You are free to watch in the background by muting your mic and camera, but you also have the option of appearing to ask a question or make a comment if you’d like.
After the regular class time has ended, students leave the virtual classroom while auditors are invited to stick around for a few minutes to ask “Teacher Questions”! This is when you would have me all to yourselves as teachers. Turn on your webcams and mics, and discuss the lesson, teaching logic in general, or whatever questions you might have.
We will meet together live for online recitations Monday/Thursday from 8:00-9:30 AM (PST), or Tuesday/Friday from 8:00-9:30 AM (PST). The spring semester starts January 5/6, 2017, and goes to May 18/19, with a Winter Break in mid-February and an Easter Break in mid-April.
We have been learning about forensic (or judicial) oratory, including the definition of wrongdoing, the elements of proving wrong, the state of mind of wrongdoers, non-technical modes of persuasion, and more. The most recent assignment was this:
Here is the forensic speech of one of my students, Daniel Seifert, defending Bucky Barnes (from “Captain America: The Winter Soldier”) of the alleged murder of Tony Stark’s parents and others.
One of the most practical lessons in Introductory Logic is Lesson 32, “Establishing Conclusions.” Here you are no longer analyzing someone else’s arguments; you are now writing your own. The hardest part of this lesson is developing an argument for a conclusion while being allowed to use any valid form. In the video for this lesson, I encourage you to find a middle term that connects to the major and minor terms in the conclusion. Let me suggest another way to continue this process.
If you understood hypothetical syllogisms well in the lesson prior, you may use them to help you develop a valid argument. For example, in Exercise 35, question 2, you are asked to establish this conclusion (straight out of Calvin and Hobbes):
Arguments in which one statement is left assumed are called enthymemes. Most logical arguments encountered in daily life are enthymemes. We can use the tools of logic to determine the assumption being made in an enthymeme.
In Lesson 29, we see that inclusive statements (employing inclusive words like whoever, whatever, whenever, etc.) are commonly used in normal English. To show this, let’s look at several examples of inclusive statements in the Bible, along with their translation into categorical form. Continue reading Translating Inclusives→
Unit 4: Arguments in Normal English in my Introductory Logic text is a difficult section, primarily because of the ambiguities within English. But if we want to be able to apply the tools for analyzing syllogisms to everyday arguments, it is essential that we understand it.
One of the more difficult parts of this difficult section ideals with translating exclusive statements into categorical form. Exclusives are statements that exclude all or part of the predicate of the subject, statements that use words like only, unless, except. Let me give some suggestions that may help. Continue reading Exclusive help→
I have received several inquiries regarding other possible solutions to the syllogism translations in Introductory Logic Exercise 27. Though the Teacher’s Edition offers only one solution per problem, there are in fact many possible correct answers to each question.
Logic students sometimes struggle with understanding and remembering immediate inferences. The more opportunities they have to see them used, the more likely they are to grasp them. Consequently, I want to give some examples of immediate inferences used in the Bible. Two equivalent immediate inferences for categorical statements are obverse and contrapositive. Continue reading Some Uses of Immediate Inference in Scripture→