## Posts tagged ‘denying the antecedent’

### DirecTV Denies the Antecedent

Have you seen the recent commercials for DirecTV, where they try to convince you to get rid of cable and sign up for their service? Here’s the transcript from one of them:

When you pay too much for cable, you throw things.
When you throw things, people think you have anger issues.
When people think you have anger issues, your schedule clears up.
When your schedule clears up, you grow a scraggly beard.
When you grow a scraggly beard, you start taking in stray animals.
And when you start taking in stray animals, you can’t stop taking in stray animals.
Stop taking in stray animals… get rid of cable.

This extended chain of conditional statements forms an invalid argument.

a (pay too much) → b (throw things)
b (throw things) → c (anger issues)
c (anger issues) → d (clear schedule)
d (clear schedule) → e (scraggly beard)
e (scraggly beard) → f (take in stray animals)
f (take in stray animals) → g (can’t stop)
-a (no cable) → -g (no stray animals)

I mean, not that I really expected a bunch of ad execs to understand the rules of logic, but this is a rather basic fallacy. It’s a covert denying the antecedent argument, where the denial (-a) happens seven steps after the initial premise (a → b).

The following is a similarly flawed argument, but the error may be more obvious due to proximity.

If you like math jokes, then you are a dork.
You do not like math jokes.
Therefore, you are not a dork.

If you don’t like math jokes, believe this argument is valid, and think you’re not a dork, look no further than the “I ♥ Anekin Skywalker” bumper sticker on your 1988 Yugo GV.

Speaking of bad logic, how’s this?

Jean-Paul Sartre is in a French café, and he says to the waitress, “May I please have a cup of coffee, with no cream.”

“I’m sorry, monsieur,” the waitress replies, “but we’re out of cream. Would it be okay if I brought you the coffee with no milk?”

The Math Jokes 4 Mathy Folks blog is an online extension to the book Math Jokes 4 Mathy Folks. The blog contains jokes submitted by readers, new jokes discovered by the author, details about speaking appearances and workshops, and other random bits of information that might be interesting to the strange folks who like math jokes.

## MJ4MF (offline version)

Math Jokes 4 Mathy Folks is available from Amazon, Borders, Barnes & Noble, NCTM, Robert D. Reed Publishers, and other purveyors of exceptional literature.