Exercise1.html

Philosophy 1100: Introduction to Ethics

Exercise 3: The Concept of Validity

Due Date: Recitation Section - Friday, September 21

Proportion of Final Grade: 5%

Instructions

1. For each of the following arguments, simply indicate whether you think that the argument is valid or invalid.

2. It is not necessary to justify your answer

3. If you are uncertain about some of the answers, use the techniques set out in the recitations - such as Venn diagrams.

1.     If she knows who he is, he's in danger.
        But she doesn't know who he is.
        Therefore, he's not in danger.
                                                                                                                        Valid ___   Invalid ___

2.     Everyone who has accepted the one true faith will go to heaven.
       Some women will go to heaven.
       Therefore, some women have accepted the one true faith.
                                                                                                                        Valid ___   Invalid ___

3.     The Pope is an unbeliever.
       All unbelievers are women.
       Therefore, the Pope is a woman.
                                                                                                                       Valid ___   Invalid ___

4.     If God exists, then there is an absolute, objective moral law.
       But there is, indeed, an absolute, objective moral law.
       Therefore, God does exist.
                                                                                                                       Valid ___   Invalid ___

5.     Fetuses are human beings.
       All human beings have a right to life.
       Therefore, fetuses have a right to life.
                                                                                                                       Valid ___   Invalid ___

6.   Stalin was an atheist.
       All Communists are atheists.
       Therefore, Stalin was a Communist.
                                                                                                                       Valid ___   Invalid ___

7.   Billy Graham is a born-again Christian.
       Only born-again Christians will go to heaven.
       Therefore, Billy Graham will go to heaven.
                                                                                                                        Valid ___   Invalid ___

8.   You can't buy illegal drugs at the local store.
       Aspirin, however, is not an illegal drug.
       Therefore, you can buy aspirin at the local store.
                                                                                                                        Valid ___   Invalid ___

9.     Pat Robertson is a known homosexual.
       No homosexuals are Christians.
       Therefore, Pat Robertson is not a Christian.
                                                                                                                        Valid ___   Invalid ___

10.   All cats are carnivores.
       Some carnivores eat mice.
       Therefore, some cats eat mice
                                                                                                                    Valid ___   Invalid ___