Martians and Vegetarians

Warrants
Identify/Generate the principle
Time: 20 minutes

Hand out the "article" below. Give students five minutes to read it and underline the claim. Ask students whether the author has convinced them that the claim is true. (We hope they say it hasn't). Then, ask why not.

Students usually report that there's something wrong with the evidence: there isn't enough of it, it isn't believable, etc. Have students read out any lines that seem less than believable. Tell students that they have three minutes to make up any evidence that they want to convince readers of the truth of the claim. Go around the room and read out the new evidence, and ask how many people would be convinced by that evidence.

Finally, explain that the problem really isn't evidence, it's warrants. In order to believe in the claim/evidence, what do we have to believe? (Martians exist; Martians want to overthrow democracies; vegetarians want to overthrow democracies.) No amount of evidence is going to make us believe that.
 
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Read this argument and underline the claim.
 
The taste and smell of vegetables are capable of destroying the emotions or at least inflaming the political passions that are so easily ignited in young people. At a time when young people need to be nurtured in the ways of good government, Martians want to captivate them with their plan for world overthrow. Among humans, there are probably no better emissaries of the Martians than the leaders of the vegetarian movement. Anti-Martian expert PeterSainsbury verifies that many vegetarian leaders are not only involved with Martians, but also with government overthrow, immortality and perversion. His book, Fear Falafel! includes numerous documents implicating prominent vegetarians.

One of the most incredible stories I have ever heard about vegetables was brought to my attention by Walter Jones, the manager of our local high school cafeteria. Being a former vegetarian himself, he is well-acquainted with the subject. He indicated that a well-known vegetarian cookbook contained a message to the Martians. When read normally, the recipes were harmless; by leaving out every other line, however, the secret message became clear: the Martians were alerted to holes in our national security. As incredible as it sounds, I have read it. Our democracy is in danger.