Don't Get Fooled (and Learn to Fool Others!)

That was the name of the lesson for spotting valid and invalid deductions. Students had to write their own examples of both valid and invalid (converse and inverse errors) deductions. Here are some of my favorites:

• If you rob a bank, you go to jail. Tim has never robbed a bank. Therefore, he's never been to jail.

• When you run, you have a healthier life. Manuel doesn't have a healthy life. Therefore, Manuel doesn't run.

• If a guy is a soccer player, then he is cute. Hector is not a soccer player. Therefore, Hector is not cute.

• If you talk to Vanessa during class, you won't get any work done. Daisy doesn't talk to Vanessa at all. Therefore, she gets all her work done.

• If you're a boy, you must not take showers. Adolfo is a boy; therefore, Adolfo must not shower.

• If you're a monkey, then you climb trees. Sara climbs trees, therefore she's a monkey.

• If you're Mexican, you should speak Spanish. Dan speaks Spanish. Therefore, he is Mexican.

• If you are Mr. Greene, then you like Voltron. Phil isn't Mr. Greene, therefore he doesn't like Voltron.

• If you're a brunette, you like sopes. Misty does not like sopes, therefore she is not a brunette.

• If you're a rat, then you eat cheese. Alondra eats cheese, therefore she is a rat.