Posts Tagged ‘logic’

Resources for a Lesson Plan on Tautologies and Circular Reasoning

January 9, 2015

A tautology is a grammatical construct; circular reasoning is a logical fallacy. The two phenomena are related but not identical.

A tautology is a sentence in which the conclusion is equivalent to its premise. In other words, in a tautology, the predicate can be surmised by reading the subject.

Here are some examples of tautologies:

My mother’s brother is my uncle.

Father Brown is a priest.

It is what it is.

A circular argument occurs when someone affirms her position simply by restating it in different terms. In other words, circular reasoning is an argument where the conclusion depends upon or is equivalent to its premise.

In a circular argument:

X is true because of Y.


Y is true because of X.

A circular argument is similar in structure to a tautology, but a circular argument includes causal reasoning (because, therefore, for this reason, etc.).

Here are some examples of circular reasoning:

My mom is terrific because she is wonderful.

People do what Dave tells; therefore, he is a great leader.

I slumbered beyond my assigned wakeup time; that’s why I overslept.

Lesson Evaluation: Explain why the following examples are tautologies, circular arguments, or neither.

Chris Rock is a hilarious comedian because he makes people laugh.

A bartender is a guy who listens to people talk all day.

Freedom’s just another word for nothing left to lose.

Anthony is extremely strong due to his ability to bench press three hundred pounds.

If aliens didn’t create the pyramids then how come pyramids are the product of technology that didn’t exist on earth at that time?

Allen hasn’t had a drink in twenty-three years, but he isn’t really sober because he doesn’t go to AA meetings and he isn’t working the steps.

A man’s gotta do what a man’s gotta do.

They are who we thought they were.

If I could tell you, I would let you know.

I stopped eating meat in 1987; that’s what makes me a vegetarian.

by Richard W. Bray

On Redundancy, Oxymora, and Grammatical Correctness

November 19, 2011

It would be redundant to say that Dave was “completely devastated” when his hamster died because there cannot be degrees of devastation. I can be extremely scared by radio reports of zombies in my neighborhood, but it would be inexact to say that I am extremely terrified. Conversely, it would be oxymoronic* to declare that Dave was only “slightly devastated” by the news of his hamster’s untimely demise.

For the poet (by which I also of course mean the novelist) the phrases completely devastated and slightly devastated have all sorts of wonderful possibilities. However, writers seeking precision with their words (students enrolled in a Freshman Composition class, for example) should avoid such phrases.

* George Carlin has helpful lists of redundancies and oxymora in his book Braindroppings


State whether the highlighted portions of the following sentences are redundant, oxymoronic, or grammatically acceptable.

1. I was a tad heartbroken when my wife left me for my younger brother.

2. My aunt is a little bit pregnant.

3. Dresden was totally incinerated by the Allied bombing.

4. Pizza is extremely overrated.

5. My cat was completely dead after the accident.

6. Gertrude was a little bit exhausted after studying six straight hours for her English exam.

7. Osvaldo was completely miserable after he lost the tiddlywinks tournament.

8. The traffic around here is somewhat slow after jai alai matches.

9. Pham was extremely furious when I told her the results from Dancing with the Stars.

10. Ted overdosed slightly on pain medication.

by Richard W. Bray