LESSON #19

Ordinary Language arguments, Translation and Enthymemes

Reading Assignment: 5.5 (pp. 285-288)  5.6 (pp. 289-291) also 4.7 (p. 241-249)

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I am not going to do a lot of explaining these sections. There isn't much I can add to the book. Keep in mind that you have two jobs. One is to translate ordinary language into standard form syllogisms. Standard form syllogisms are made out of standard form propositions. The other is filling in an unstated premise or conclusion, in an enthymeme.

Enthymemes are mostly reconstructed using common-sense. An enthymeme is an argument which is missing a premise or the conclusion. The missing statement is implicit, but you will need to make it explicit.

Don't worry about translating the argument into a categorical syllogism until you have filled in the missing statement.

Utilize premise and conclusion indicator words as clues as you need.

You will usually be correct if you simply relax and write down your first reaction. You should then carefully examine your reconstructed argument to see if it makes sense.

Once you have written down the missing statement, refer back to section 4.7 if you need help translating the statements of the syllogism into standard form propositions.

Then check to make sure your major and minor premises are on the correct order. (I'm assuming you automatically put the conclusion last.)

ASSIGNMENT 1: (10 points each)

Supply the missing premise or conclusion for the following enthymemes. All the arguments can be made valid.

1. This cannot be a rose bush because it does not have thorns.

2. All of my students are intelligent, so George cannot be one of my students.

3. Only geraniums grow in the east garden, and these flowers on the table were picked from there this morning.

4. Dr. Jones cannot be a psychiatrist because his name is not in the Medical Directory.

5. Deadheads are not aggressive, so Judy cannot be a deadhead.

 

ASSIGNMENT 2: (10 points each)

Translate the above (reconstructed) arguments into Standard Form Categorical Syllogisms. Be sure that they are in standard form! Then test for validity using any of the methods learned in Chapter 5. All should be valid.

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