Logic in a Nutshell

Exercise L4:  Logical Fallacies

Instructions:  Identify the logical fallacies in the following passages.  Please note that an answer key has been provided for Part A.

Part A:  Practice Questions

1. Women are so sentimental!  My mother and sister always cry at the movies.  My father and I never do.

2. No breath of scandal has ever touched the senator.  Therefore he must be incorruptibly honest.

3. How can you take Sartre's philosophical views seriously.  The man, after all, led an abysmal life and and was certainly no paragon of morality.

4. After all, my views on gun control have been endorsed by some of Hollywood's most notable actors---Sylvester Stallone, Barbara Streisand, and Alec Balwain, among others.  How could you not agree with me?

5. Gentlemen, we can not let Honduras be ruled by a communist government. If we do then sooner or later Mexico will become communist along with the islands in the Caribbean and no doubt Canada.

     Answer Key for Practice Questions

Part B:  Homework Assignment

1. The governor supports tax increases for middle-income earners. This doesn’t surprise me. He has always been against unions and this is just another measure designed to undermine them. If we allow for these tax increases and the undermining of unions, democracy in this country will be threatened.
2. It is necessary to confine criminals and to lock up dangerous lunatics. Therefore there is nothing intrinsically wrong with depriving people of their liberties.
3. If you hold that nothing is self-evident, I will not argue with you for it is clear that you are a quibbler and not to be convinced.
4. God exists because the Bible tells us so, and we know what the Bible tells us is true because it is the revealed word of God.
5. Narcotics are habit forming. Therefore if you allow your physician to ease your pain with an opiate you will become a hopeless drug addict.
6. You can’t park here. I don’t care what the sign says. If you don’t drive on, I’ll give you a ticket.
7. I also admit that there are people for whom the reality of the external world constitutes a grave problem. My answer is that I do not address them, but that I presuppose a minimum of reason in my readers.
8. She says that she loves me and she must be telling the truth, because she certainly wouldn’t lie to someone that she loves.
9. There is no proof that the secretary "leaked" the news to the papers, so it couldn’t have been the secretary who did it.
10. Gentlemen, I am sure that if you think it over you will see that my suggestion has real merit. It is only a suggestion of course, and not an order. As I mentioned at our last conference, I am planning to reorganize the whole business. I still hope, however, that it will not be necessary to curtail the operations of your department.
11. The Rolls-Royce is a foreign made automobile and gets very few miles per gallon. Therefore all foreign made automobiles get very few miles per gallon.
12. Two students were having a disagreement about cars. Student A said, "I can prove to you that Toyota Carolla’s are faster than Honda Civic’s. John owns a Carolla and he told me he beats very Civic he has ever raced." Student B asked, "How do you know John is telling the truth?" Student A replied by saying, "Someone who drives the fastest car wouldn’t have to lie."