Identifying
the premises and conclusions of arguments. Determine if there is an argument
present and identify the premises (Pn) and conclusion (Cn). Label
only those premises relevant to the conclusion(s).
1. Flutes must use reeds, because all woodwind instruments use reeds, and flutes are woodwind instruments.
2. Since last summer, when he hitched around Europe playing music on the street, he takes his flute everywhere.
3. Since a clarinet requires reeds, it must not be a brass instrument.
4. Carl was angry because he had no music stand.
5. Hector hates jazz, so he shouldn't play jazz.
6. Hector hates jazz. Because of this, he didn't play with our group.
Identifying
the premises and conclusions of arguments. Determine if there is an argument
present and identify the premises (Pn) and conclusion (Cn). Label
only those premises relevant to the conclusion(s).
1. All people should have equal political rights, because there is nothing that differentiates people at a birth in a way that is relevant to their political rights.
2. We -- the governors in a democracy -- must make intelligent decisions when we vote. Without a free flow of information, we cannot make intelligent decisions. Thus there must be freedom of speech in a democracy.
3. The other day, my wife and I tried to take a boat ride that would ordinarily last just 20 minutes. As we left our marina, we were stopped by the county sheriff's boat for a sobriety test and a thorough safety inspection. As we re-entered the marina, we were stopped by the state police boat for another sobriety test. We support the enforcement of safety laws, but when boaters who have not been drinking and who show no signs of intoxication are stopped twice, increasing a 20-minute outing to an hour-long ordeal, that is harassment.
4. Abortion is the destruction of an unborn baby. A new human life begins as soon as the egg has been fertilized. Science reveals without question that once the egg is fertilized, every identifying characteristic of a brand new human being is present, even the color of the eyes and hair, the sex and everything else. Pregnancy is the period for this new human life to mature, not to "become human" -- it already is.
Determining validity and invalidity. For each example, a) identify if there is an argument, and if so, the premises and the conclusion, b) determine if the argument is valid, and c) say why it is or is not sound.
1. All doctors are musicians.
Some doctors play chess.
So some musicians must play chess.
2.
Some dogs howl.
Some dogs swim.
So some dogs that howl swim.
3.
All faculty members support the main goals of the striking workers.
Every department chair is a faculty member.
So every department chair supports the main goals of the striking workers.
4.
All faculty members support the main goals of the striking workers.
Some department chairs are faculty members.
So some department chairs support the main goals of the striking workers.
Determining validity and invalidity. For each example, a) identify if there is an argument, and if so, the premises and the conclusion, b) determine if the argument is valid, and c) say why it is or is not sound.
1. All doctors have degrees, and all lawyers have degrees. So at least some doctors must be lawyers.
2. Every doctor is a lawyer. Every lawyer has a degree. So every doctor must have a degree.
3. Some surgeons are lawyers, but no lawyers have studied medicine. So some surgeons haven't studied medicine.
4. Every surgeon in New York is licensed to do surgery. Some doctors are surgeons in New York. Thus some doctors are licensed to do surgery.
5. Doctors and lawyers have clients, and they are also similar in other ways.
6. At least some doctors perform surgery, so, since no lawyers perform surgery, not all doctors are lawyers.
Equivocations: Identify the conclusion of
argument and say whether the argument is valid. If not, note and analyze the
equivocation being made.
1. We have seen miracles – like people walking on the moon. So we know that we can believe in the miracles that the Bible describes.
2. Equal rights for women should not be constitutionally guaranteed. Men and women are different, physiologically and emotionally. If this is so, then men and women are not equal; and if men and women are not equal, then the law should not treat them as equals.
3. The human species is omnivorous, partaking of a diet that includes both meat and vegetables. People who argue for vegetarianism aren't just making a logical mistake; they are asking the impossible --- that humans go against their humanity!
Identifying
informal fallacies. Name or describe the
fallacy committed and analyze the difficulty it introduces.
1. Either God exists or we are just biological organisms reacting to stimuli. Clearly we think of ourselves and others as more than that.
2. Eighteen-year-olds shouldn’t have the right to vote because if they aren’t old enough to drink at that age, they aren’t responsible enough to vote.
3. Everyone in the room thinks that John stole the money, so I wouldn't speak out on his behalf of him if I were you.
4. We can go out to dinner tonight and have a thick, juicy steak at the Scotch and Sirloin Restaurant, or we can have a thin, dry one at the Big Sky Steak House.
5. Those who support abortion believe that a woman has the right to kill another human being. We know that nobody has that right, though, so abortion should not be legal.
6. If the President signs the bill, it will become law. The President will sign the bill, so it will become law.
7. The welfare system gives every low-life the kind of life that others have had to work hard for. People who pull themselves up by their boot-straps and work to make an economic contribution deserve what they earn; but the welfare system just rewards the undeserving.
8. You can insult me all you want, but we'll see who is right when I tell your girlfriend.
9. I do not mind working long hours to produce the results that you requested, but I hope that you appreciate the personal time I have devoted to this project. I look forward to your appraisal.
10. We need better controls on guns. The other side opposes controls because registering guns is inconvenient. Buit without more controls on guns, violence in the cities will continue to escalate. A little inconvenience in filling out a few forms or in waiting for a background check is not too high a price to pay for safer cities.
Evaluating
analogies. Identify the source, target, and
any connecting principles evident. Construct one disanalogy based on the
similarities provided.
1. Politicians are like doctors. They are there to cure the ills of the economy. When you go to a doctor, you acknowledge that he or she knows more about your health than you do, and you pay for the advice you get. There is no point in going to a doctor if you are not prepared to follow that advice. Similarly, there is no point in electing politicians if you are not going to give them free rein to act after they are in office. Criticizing politicians defeats them and defeats yourself, and it's just as silly as going to the doctor and then refusing to follow the advice you get.
2. A presidential campaign is like a marathon race. You have to be in it for the long haul, able to keep going against every challenge, even when there are others ahead of you. Just as we are glad when the best runner wins a marathon race, we should be glad when the person who runs the best campaign becomes President.
3. The way I look at it, the liver is like a muscle. Just as you keep a muscle in shape by exercising it, you need to exercise your liver by drinking an ample quantity of alcoholic beverages.
4. Censoring dangerous material and taking antibiotics have a lot in common. Antibiotics will usually kill the harmful bacteria in your body, but at the same time, they will kill good bacteria, because the medicine does not distinguish between the good and the bad. Although censorship may eliminate unwanted speech and writing, we could also risk losing valuable information and ideas.
5. The courts have ruled that a woman has a legal right to an abortion. Some people have jumped to the conclusion that because of this, the government has to pay for abortions for Medicaid patients. There is a constitutional right to privacy, but the government has no obligation to pay for anyone's window shades.
6. Men are like dogs. Women prepare their meals and do everything to keep them content. Men count on women like dogs count on their owners. Like dogs, men are not satisfied with this good treatment. They get fidgety and begin to sniff out new territory and eventually find someone new dishing out the bones.