Posts Tagged ‘critical thinking’

A Few Notes on Teaching Logical Fallacies

July 3, 2016
Ted Haggard

Ted Haggard


Have you ever been arguing with someone and you felt that there was something wrong with her argument, but you couldn’t figure out what it was? Perhaps she was utilizing some form of logical fallacy. A fallacy is an unsound argument based on faulty reasoning. Logicians have identified scores of fallacies.

Here are some examples of common logical fallicies:

Appeal to fear

Are you sure you want to give me a ticket, officer? I play golf with the chief of police.”

Things could get pretty ugly around here if I don’t get what I want.

Appeal to pity

You should go out with me because forty-three women have already turned me down and I can’t take much more rejection.

Circular Reasoning (A=B because B=A)

Lebron James is the greatest basketball player of his generation because nobody else is as good as he is.

My mom is terrific because she is wonderful.

Appeal to Common Practice

It’s no big deal to leave trash on the ground in a parking lot. A lot of people do it.

But Mom, all the other parents let their kids stay out until dawn, so you should too.

Post hoc (causal) fallacy

When the rooster crows, the sun rises. Therefore, the rooster causes the sun to rise.

The Lakers won last night because I wore my lucky sweater.

False Dilemma (or False Alternatives)

It will either be hot or cold tomorrow.

You must be a Lakers fan or a Clippers fan.

Slippery Slope

If we allow gay marriage, people will start marrying their dogs.

If we ban Hummers because they are bad for the environment, eventually the government will ban all cars.

Non Sequitur (“It does not follow”)

That man is an awful person because he is wearing a blue sweater.

I cannot eat a cupcake because it is Tuesday.

Loaded question

Have you stopped wetting your bed yet?

Do you still have a Spongebob lunch pail?

Distinction without a Difference

I’m against capital punishment, but I believe we should execute serial killers.

I don’t have a sweet tooth; I just love to eat candy.

One of the most common fallacies is ad hominem, which means attacking a person instead of addressing her arguments.

Here are two examples of irrelevant ad hominem argument which have nothing to do with the legitimacy of a person’s arguments:


Dave: I think the death penalty is a good idea.
Larry: Who cares what you think? You are a stupid, pathetic loser and your mother dresses you funny.


I’m not going to listen to any of your arguments because you wear Member’s Only jackets and you sleep with a Teddy Bear.

An Ad hominem argument is a great way to avoid the merits of another person’s arguments? Many English teachers say that it is never appropriate to engage in ad hominem arguments.  But is it legitimate to attack a person for being hypocritical? My answer is: Sometimes.

Here is an example of a situation where an ad hominem argument is clearly inappropriate:

Let’s say my doctor tells me after a checkup that my blood pressure is too high and I need to lose weight and I should quit drinking and smoking.   I respond: “What are you talking about, Dude? I see you drinking and smoking at my bar every night and you are seriously overweight.

My ad hominem is illegitimate in this case because my doctor is giving me medically viable advice even though he doesn’t practice what he preaches. He went to medical school and he knows what he’s talking about.

Here is an example of a situation where an ad hominem argument is appropriate:

Speaking of practicing what we preach, what about someone like megachurch preacher Ted Haggard who righteously espouses clean living and family values—until he gets caught in a hotel room with a male masseur and a bunch of meth? Does Haggard’s behavior render his message any less legitimate?  Yes, because he is bolstering his argument by holding himself up of as a paragon of someone who is living a righteous lifestyle.

by Richard W. Bray

A Critical Thinking Story Evaluation Activity for High School Students and an Amusing Teacher Story (by Brian)

October 20, 2010

A lesson plan for a critical reading of The Interlopers by Saki

: High School English

Objective: Students will demonstrate higher order critical reading and reflection skills

Materials: a class set of The Interlopers, coloring markers, two-by-two sheets of butcher paper.


Students will read the story the night before and come to class with written responses to the following questions:

1) How did you connect personally to the story?
2) What questions would you like to ask the author and/or the characters?
3) What strategies did you utilize to clarify any segments of the story that were unclear to you?

Classroom Activity

a. Teacher groups students
b. Students in each group use their homework to come to a consensus on two statements for each category
c. Group leaders submit written proposals to the teacher who okays them and distributes butcher paper and markers to students
d. Students make posters containing a picture of the scene that best represents the theme of the story, a prediction based on the ending of the story, and the six answers generated from homework assignment


Groups present their posters explaining whether their clarifications, questions, and connections are inferences or evaluations in a question and answer session with the class.

Why I no longer Have Show-and-Tell on the Second day of Class

It was my second year teaching at the university and I had my students bring an item to the second class meeting that represented them, and I had them do a short presentation. Well “Carl” showed up with an old two liter bottle of coke that had been converted into a terrarium. I didn’t think much of it until he volunteered to go first.

He went up to the front of the class and opened up the bottle and reached inside and pulled out a rather large pet black-widow spider named Helen. He let it crawl on his hands, and I swear he even pet it. About this time, the entire class and I moved to the back of the classroom while a large man who had been sitting in front bolted out the door. Carl asked if anyone wanted to hold his “pet” –there were no takers.

I then attempted to walk up to the front and said, This is very nice, can you please put Helen back in her cage? He did without further incident, and the class then got back to normal. A few more people then decided to complete their presentations, and just as we were about to get to work for the evening, I heard a knock at the door and Victor, our large runner, was asking if the spider was gone.

(You can reach Brian at