## Chapter 10: DISJUNCTIVE AND HYPOTHETICAL SYLLOGISMS - Practice -

Multiple Choice:
Click on the button next to the answer you wish to select. Your results will be displayed immediately in the question's text box.

No. of Questions = 30
In these exercises, you will be given hypothetical or disjunctive syllogisms, and asked to determine whether they are Valid or Invalid.

There are two levels of difficulty. In level (a) questions 1-15, then syllogisms will all be in standard form; in level (b) questions 16-30, they may be in standard or nonstandard form.

 1. If I win the lottery, then I'll quit my job If I quit my job, then I'll be unemployedTherefore, if I win the lottery, then I will be unemployed a) Valid b) Invalid 2. John is either a knave or a fool He is not a foolTherefore, he is a knave a) Valid b) Invalid 3. If the tomato is a fruit, then it contains seedsThe tomato is a fruit Therefore it contains seeds a) Valid b) Invalid 4. If there were no reindeer, Santa Claus would not exist Santa Claus does existTherefore, there are reindeer a) Valid b) Invalid 5. If ice were heavier than water, ponds would freeze solid in winter Ice is not heavier than water Therefore, ponds do not freeze solid in winter a) Valid b) Invalid 6. Either wealth is evil or it is good Wealth is not evil Therefore, wealth is good a) Valid b) Invalid 7. If his clothing carries traces of radioactivity, then he was in the area His clothing carries no traces of radioactivity Therefore, he was not in the area a) Valid b) Invalid 8. If this is not a terrific deal, then my name's not Donald Trump My name is not Donald Trump Therefore, this is not a terrific deal a) Valid b) Invalid 9. If two snowflakes ever formed under identical conditions, they would have the same shape Two snowflakes never form under identical conditions Therefore, two snowflakes never have the same shape a) Valid b) Invalid 10. If astrology had any validity, the predictions of astrologers would be more accurate than sheer guessing The predictions of astrologers are not more accurate than sheer guessing Therefore, astrology has no validity a) Valid b) Invalid 11. If the fetus is an actual human being, then it has a right to life The fetus is not an actual human being Therefore, it does not have a right to life a) Valid b) Invalid 12. If Melanie is a champion windsurfer, then she must have good balance Melanie has good balance Therefore, Melanie is a champion windsurfer a) Valid b) Invalid 13. If used car dealers were not aware of defects in the cars on their lots, they would not stay in business long They do stay in business long Therefore, used car dealers are aware of defects in the cars on their lots a) Valid b) Invalid 14. If Israel allows the creation of a Palestinian state on the West Bank, its own survival will be jeopardized If Israel's survival is jeopardized, violence in the Middle East will increase Therefore, if Israel allows the creation of a Palestinian state on the West Bank, violence in the Middle East will increase. a) Valid b) Invalid 15. He'll leave town if he knows what's good for him He knows what's good for him Therefore, he'll leave town a) Valid b) Invalid 16. If the island of Thera exploded around 1550 BC, then Crete would have been inundated Crete was inundated Therefore, the island of Thera exploded around 1550 BC a) Valid b) Invalid 17. Whenever Sally finishes a crossword puzzle, she does a little jig Sally is doing a little jig Therefore, Sally finished the crossword puzzle a) Valid b) Invalid 18. If the account of creation in Genesis is literally correct, then the sun was not created until the fourth day If the sun was not created until the fourth day, then the word "day" cannot be taken literally to mean one cycle of sunrise and sunset Therefore, if the account of creation in Genesis is literally correct, the word "day" cannot be taken literally to mean one cycle of sunrise and sunset a) Valid b) Invalid 19. She will not graduate unless she passes geology She will pass geology Therefore, she will graduate a) Valid b) Invalid 20. A figure is a triangle if and only if its internal angles are equal to two right angles This is not a triangle Therefore its internal angles do not equal two right angles a) Valid b) Invalid 21. If the human mind were an information processing system like a computer, then creativity would be hard to explain Creativity is hard to explain Therefore, the human mind is not an information processing system like a computer a) Valid b) Invalid 22. The show is over only if the fat lady has sung The show is over Therefore, the fat lady has sung a) Valid b) Invalid 23. A person cannot love both God and Mammon Marjorie loves Mammon Marjorie does not love God a) Valid b) Invalid 24. The anti-clot medicine TPA may be sold if and only if it has been approved by the FDA It has been approved by the FDA Therefore, it may be sold a) Valid b) Invalid 25. Smith would have been convicted only if the jury believed the star witness Smith was not convicted Therefore, the jury did not believe the star witness a) Valid b) Invalid 26. She will get into medical school only if she does very well on the MCAT She did very well on the MCAT Therefore, she will get into medical school a) Valid b) Invalid 27. The President was obligated to notify Congress about sending troops and ships to the Persian Gulf unless considerations of national security prevented him Considerations of national security did not prevent him Therefore, the President was obligated to notify Congress about sending troops and ships to the Persian Gulf a) Valid b) Invalid 28. If organic molecules can form spontaneously in a liquid containing the chemical building blocks, then life could have emerged in the oceans of the earth without outside intervention Organic molecules can form spontaneously in a liquid containing the chemical building blocks Therefore, life could have emerged in the oceans of the earth without outside intervention a) Valid b) Invalid 29. Only if a candidate has lots of money will he run successfully for national office Ronald Reagan ran successfully for national office Therefore, Ronald Reagan had lots of money a) Valid b) Invalid 30. Joe Candidate is running for President either because he has a vision of what's good for the country or because he wants the power and prestige of the office Joe Candidate is running for President because he wants the power and prestige of the office Therefore, he is not running for President because he has a vision of what's good for the country a) Valid b) Invalid