Questions with no answers are in your textbook and here.
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).
Y 1. [P1]No brass instruments use reeds, and [P2]flutes don't use reeds, so [C1]flutes must be brass instruments.
N 2. After a hard day of rehearsals, John loves to sit in a quiet meadow where he can hear only the birds.
Y 3. [P1]Betty will be angry unless someone else brings the music stands. But [P2]if Ann doesn't bring them, no one will. [C1]So either Ann will bring the music stands or Betty will be angry.
N 4. When I hear you play like that, it makes me so angry that I want to smash your flute and break your jaw.
N 5. If Hector hates jazz, then he shouldn't play it.
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. [P1] If we don't consolidate city and county school systems, the city school system will continue to deteriorate, producing a large number of young adults who are not equipped to find work that will keep them out of poverty. [P2]We must not allow this disastrous social situation to occur, so [C1] we must consolidate city and county schools.
2. [P1]Many herbs are known to have medicinal properties. So [C1]it is not a waste of taxpayer dollars to finance trials of herbal treatments that appear implausible. Open-mindedness is a friend of scientific investigation, and since [P2] herbal treatments are widely used, [C2] it is important to determine whether they work and whether they have any harmful effects.
3. [P1] A steady movement of people from the city to suburban and rural areas has decreased the city's population, increased the percentage of its population that are poor, and increased the percentage of its population that are African-American and Hispanic. [P2]If the tax base continues to shrink, then the resulting poor support for education and services, combined with racial and ethnic polarization, will lead to increasing tension between city and suburban populations. [P3]We must stop this trend. [P4]The only way to stop it is by consolidating city and county governments, so that there is a single tax base in support of a unified, high quality system of education and a uniform level of municipal services.
[Implicit C1] We must consolidate city and county governments.
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.
A. Y
[P1]Every dog is a mammal. Valid
[P2]No pets are mammals.
[C1]So no dogs are pets.
Unsound: There are pets that are mammals (cats, etc.)
B. Y
[P1]All Olympic skiers train hard. Invalid
[P2]Some people who train hard ride bicycles when training.
[C1]So some Olympic skiers ride bicycles when training.
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.
N 1. Not all doctors have degrees, but all lawyers have degrees. Also, since 1900, no doctors have been lawyers.
There is no indication that one statement is presented as a reason that another is true, so there is no argument.
Y Valid 2. [P1]Since all doctors have degrees, and [P2]anyone who has a degree has attended school, [C1]every doctor must have attended school.
Sound: To be a ‘real’ doctor, you must have obtained a degree. (or Unsound: There are some ‘practicing doctors’ that might not have degrees; aka charlatans).
N 3. Not all doctors do surgery. Some lawyers do medical counseling. But every doctor who does surgery does medical counseling.
No argument.
Y Valid 4. [P1]Whenever a person eats broccoli often, he or she is able to play the saxophone. [P2]George Bush was not able to play the saxophone. So, [C1]George Bush must not have eaten broccoli often.
Unsound: There’s no relation between eating broccoli and playing saxophone.
Equivocations: Identify the conclusion of
argument and say whether the argument is valid. If not, note and analyze the
equivocation being made.
1. Although the President traveled around the nation promising that his administration would enhance our security, we don’t see it in our neighborhood. Our cars and homes are subject to regular vandalism, making us feel nervous and angry every day. Security needs to begin at home, and we should not re-elect a President who can’t keep his promises.
Equivocation on security. It is likely that the President would have been talking mainly about national security – our military defense and foreign policy – which is irrelevant to neighborhood vandalism. That is, the argument slips between security = military defense and security = neighborhood vandalism.
2. Our curriculum requires the study of basics, like English composition, mathematical skills, and use of a foreign language. Philosophy, which is the most basic study of all, should be included in this category.
Equivocation on basic. Moves from basic = basic skill for further study to basic = foundational study and criticism. Philosophy seems to be the latter but not the former.
3. Professors and other teachers should not try to cultivate independent thinking in their students. Independent thinkers would have to start from scratch, and there would be no point in that. Students should forget about trying for independence and should learn from their masters.
Equivocation on independent. Moves from independent = not bound by instructor’s opinions to independent = not assuming anything at all. This is attacking a notion of independent thinking that is probably irrelevant to any discussion that ever defended independent thinking. Independent thinkers are not afraid to try new ideas, but that does not require ignoring what has been learned.
Identifying
informal fallacies. Name or describe the
fallacy committed and analyze the difficulty it introduces.
1. At first she will study in the evening, after cleaning the kitchen, when the children are sleeping. But as exams approach and papers are due, she will gradually neglect more and more of the housework: She will not cook, the shopping won't be done, and she will even forget to check her daughter's homework and take her son to his doctor's appointment. Eventually the whole family will be in immense chaos. Nobody should try to finish a degree and care for small children at the same time.
Slippery slope (causal).
2. We need more government regulation of the media. TV news becomes more and more influential every year, and as the Sesame Street generation comes of age, it is coming to be their sole source of information. If the situation is not brought in check, the news anchors on the major networks will have more influence than the President.
False dilemma and/or slippery slope
3. If you did well on that test, you're smart. But you didn't do well on that test, so you're not smart.
Denying the antecedent
4. Finishing my degree is important for my self-esteem, because graduating is essential for my own sense of worth.
Circular
5. Never let your neighbor borrow anything. First it's a cup of sugar, then your favorite scarf, and the next thing you know she'll want to borrow your spouse to do some "jobs" around the house.
Slippery slope (causal)
6. If I spend a good portion of my time learning the computer, then I will learn to work efficiently. I have not spent much time on the computer, so I do not work efficiently.
Denying the antecedent. (You may think this is a false dilemma because the second sentence by itself could be interpreted in this way (since the second sentence, together with the false disjunction "Either I have spent much time on the computer or I do not work efficiently" would make a valid argument) However, that ignores the first sentence.)
7. Despite the fact that he had several relationships with other women during his marriage, he was never disloyal to his wife, because he always told her the truth about his affairs.
Equivocation ('disloyal' can mean cheating or not telling the truth. The latter is more specific than the former.)
8. All survivors are strong, because only the strong survive.
Circular
9. If I don't go to class, then I won't pass the course. But I attend regularly, so I'm sure to pass.
Denying the antecedent
10. In one of his songs, jazz and blues singer Mose Allison describes someone by saying, "Your mind is on vacation, but your mouth is workin' overtime." Apparently some people oppose campus speech codes because they believe that the condition described in the song is perfectly all right for college students. We should expect more, though. Campus speech codes require you to think before you speak, and everyone should favor such a standard in a university community.
Straw man. Presumably no one opposes campus speech codes for that reason.
Evaluating
analogies. Identify the source, target, and
any connecting principles evident. Construct one disanalogy based on the
similarities provided.
1. Children are like slaves. Their parents can make their major decisions for them --- where they go to school, where they live, what clothes they will have, whom they will associate with, and what they will have available to eat. Children are not even allowed to vote, presumably because it is thought that their parents' votes will adequately represent them.
It is time for us to recognize that a new era of emancipation should be before us! Just as we freed the slaves, we should free our children from this tyranny, allowing them to make their own choices and control their own lives.
Target: children
Source: slaves
General principle: Whenever people's major life decisions are made for
them, those people should be emancipated from this condition.
Disanalogy: Children, if ‘free’ could not be in a position to be responsible
citizens on par with those who are currently free.
2. It takes pressure from parents and teachers to motivate kids to study and learn to solve mathematical problems. With similar pressure, kids could learn to solve emotional problems as well. They get almost no training in this important skill now.
Target: learning to solve emotional problems
Source: learning to solve math problems
General principle: Pressure from adults to motivate kids to study and
learn can help them to solve problems.
Disanalogy: There are straightforward rules for solving math problems
that apply equally well in similar situations.
3. A good criminal trial is like a boxing match. The defense must respond to each punch the prosecutor throws, and the trial judge, like a referee, must make sure that the contest stays within the rules. The process of allowing appeals of a verdict, with a new judge and a new set of arguments, is like having a new fight to decide who really won the first one. This process would be absurd in the case of boxing, and it is equally absurd in a criminal trial.
Target: appeals of criminal trials
Source: re-doing a boxing match
General principle: Once a contest is over, you should not run another
contest to try to determine the winner of the first one.
Disanalogy: A trial has rules for achieving extrinsic purposes – finding
the truth and protecting people's rights in the process. So the verdict can
be wrong in a way that is impossible for a boxing match to be wrong.