Homework
Argument Forms
Exercise:
For each of the following arguments, (a) label the form the argument takes. Then, (b) label
the argument as ‘deductive’ or ‘inductive’.
Example:
Either the United States will attack Iran or Israel will attack Iran. However, it is
unlikely that the United States will attack Iran. The United States can ill-afford all the
anti-American sentiment that will result in the Middle East from an attack. Therefore,
Israel will attack Iran.
Answer: (a) Disjunctive syllogism; (b) deductive
1. We tell people not to speed, but equip cars with air bags in case they do. So what’s
wrong with telling kids not to have sex, but making Plan B available in case they do?
2. If interest rates go down any further, there will be no incentive for people to buy
government bonds. If there is no incentive for people to buy government bonds, they will
pretty much stop buying them. So, if interest rates go down any further, people will stop
buying government bonds.
3. Either Jesus was telling the truth when he said he was the son of God or he was insane.
But he wasn’t insane, so he was actually the son of God.
4. If the tectonic plates under the Atlantic Ocean are moving apart, there will be volcanic
activity in Iceland – and there is volcanic activity in Iceland. So the tectonic plates are
separating.
5. All men are human beings. All human beings are women. So, all men are women.
6. All the Parisians I spoke to during my trip to Europe were nice people. Parisians are nice
folks, aren’t they?
7. Xavier is a student at Orchard College, where 80% of students complete their
undergraduate degree within 5 years. So Xavier has a good chance of getting his degree.
8. Barbara is a liberal. She’s a strong advocate of environmentalism and most
environmentalists are liberals.
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9. No Greek philosopher taught in a university, but some Greek philosophers were great
thinks. Therefore, some great thinkers have not taught in a university.
10. The fossil record shows that certain dinosaurs, like birds, were capable of winged flight.
Although the birds that exist today are different in many ways, they do share a number of
anatomical features with that class of dinosaurs, including scales, hollow bones,
expanded pneumatic sinuses in the skull, 3-fingered opposable hands, and 4-toed feet.
We can conclude that dinosaurs were capable of winged flight as well.
11. If George Washington was beheaded, then George Washington died. George
Washington was beheaded. Therefore, George Washington died.
12. All members of the Phi Sigma Nu frat are bachelors. So, all members of the Phi Sigma
Nu frat are unmarried males.
13. If Fox News is a propaganda machine, then it misleads its viewers. Fox News is a
propaganda machine. Therefore, Fox News misleads its viewers.
14. We can conclude that the Milky Way is one of millions of galaxies in the universe
because Michio Kaku, a world famous physicist, has written this in his newest book on
the cosmos.
15. Four people from our party got sick after eating the shell fish at Brother Jimmy’s
Restaurant in Manhattan. I think we can conclude that the shell fish contained salmonella
or was not cooked properly.
16. Boyle’s law states that the pressure exerted by a gas on the walls of its container is
inversely proportional to the volume. Applying this law, we conclude that when we
reduce the volume of our laboratory sample by half, the pressure will double.
17. People have been listening to rock and roll music for over a hundred years. Probably
people will still be listening to it a year from now.
18. If President Barack Obama was born in Massachusetts, then he is a native of New
England. Barack Obama is not a native of New England. Therefore, Barak Obama was
not born in Massachusetts.
19. Cholesterol is endogenous with humans. Therefore, it is manufactured inside the human
body.
20. Some general managers were baseball players. Some baseball players are PED users.
Therefore, some general managers were PED users.
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