Summarize Argument
The author concludes a government’s social policies can’t be determined using only general principles of justice. Why not? Because defending any policy—such as provisions for the elderly—on the grounds of social justice eventually requires invoking arbitrary choices or circumstances specific to that policy.
Notable Assumptions
The author assumes there’s no other policy, besides those mentioned, that can be determined by general principle without relying on arbitrary choices or specific circumstances. In addition, he assumes there’s no general principle of justice that’s capable of fully determining a policy about provisions for the elderly.
A
Although two socialist states each adhered to the same electoral principles, one had a different type of machine for counting ballots in public elections than the other did.
This concerns electoral principles and policies, not principles of justice and social policies. Since the author’s principle refers only to social policies, this example is irrelevant.
B
Two democratic industrial states, both subscribing to capitalistic economic principles, differed markedly in the respective proportions of land they devoted to forestry.
This example concerns land distribution, not social policies. There’s no indication the states’ social policies are the reason they devote different amounts of land to forestry.
C
Although each adhered to its own principles, a democracy and a monarchy each had the same distribution of wealth in its population.
This gets the desired structure backward. It refers to states with different principles but similar outcomes, whereas the author argues states with similar principles will have different policy details.
D
Two states founded on and adhering to similar principles of justice had different requirements that had to be met in order to be eligible for government-subsidized day care.
This is an example of the point argued by the author. It shows two states with similar principles of justice can have social policies with different details.
E
Two societies based on different principles of justice, each adhering to its own principles, had the same unemployment benefits.
This gets the desired structure backward. It refers to states with different principles of justice but similar policies, whereas the author argues states with similar principles of justice will have differences in their policies.
Summary
Most people who invest don’t do their own research. Of this group, some rely on their broker and others on instinct. A minority of people who invest conduct their own research. Of this group, some occasionally do their own research, while others always do their own research. Most people (of all those who invest) make a profit.
Notable Valid Inferences
Less than half of the people who invest in the stock market do their own research. Some people who don’t do their own research make a profit.
A
Some people who make a profit on their investments in the stock market do so without doing any research of their own.
This must be true. If most people who invest don’t do any research, and most people who invest also profit, there must be some people who belong to both groups. In other words, there must be overlap, as both groups encompass more than half of all people who invest.
B
Most people who invest in the stock market either rely solely on their broker or make decisions based merely on hunches.
This could be false. Most people who invest don’t do their own research; of this majority, some rely on their broker and others on hunches. There could be a third sub-group that relies on something other than a broker or hunches. We can’t assume these are the only sub-groups.
C
Some people who do investment research on their own, while just as often relying on their broker or on hunches, make a profit in the stock market.
This could be false. We don’t know how large the group of people who do some research while also relying on brokers or hunches is, but we do know they belong to the minority of people who do their own research. They could also be in the minority who don’t profit.
D
Most people who invest in the stock market without doing any research of their own make a profit.
This could be false. We know some people who invest without doing research make a profit—we have no reason to believe most of them do.
E
Most people who rely solely on their broker rather than on hunches make a profit in the stock market.
This could be false. We know most people who invest don’t do their own research: within this group, some people make a profit and some rely solely on their broker. We don’t know if these groups overlap and how many people (if any) who rely solely on their broker make a profit.
A
there may be many forms of dangerous radiation other than X-rays and the kinds of radiation absorbed by members of commercial airline flight crews
Other forms of dangerous radiation are irrelevant. The author is only concerned with the dangers of radiation from commercial airline flights and dental X-rays.
B
receiving a dental X-ray may mitigate other health risks, whereas flying does not
Whether X-rays or flights may mitigate other health risks is irrelevant. The argument only focuses on the dangers of radiation put out by flights and X-rays.
C
exposure to X-rays of higher intensity than dental X-rays may be harmful
Higher-intensity X-rays are irrelevant. The argument is only concerned with the radiation put out by dental X-rays and flights.
D
the longer and the more often one is exposed to radiation, the more radiation one absorbs and the more seriously one is harmed
The author fails to consider this. If members of commercial flight crews go on a lot of flights, the low levels of nearly harmless radiation they absorb on each flight could eventually add up and harm them.
E
flying at high altitude involves risks in addition to exposure to minor radiation
Risks posed by altitude are irrelevant. The author just argues that radiation from commercial flights poses little danger to commercial flight crews.
Summarize Argument
The author concludes more funding should be directed toward intervention research in order to explore a cost-effective way to help people predisposed to mental disorders. Why? Because more research is needed to confirm some existing research—which found that early intervention can mitigate risk factors for mental disorders—and to develop practices for care based on those results.
Notable Assumptions
The author assumes the care practices developed will be cost-effective while addressing risk factors for mental disorders. She assumes more funding for intervention research will be directed towards the “comprehensive research program” described, that more funding is required for such a program, and that such a program is necessary to confirm the findings of the limited research.
A
Most minor mental disorders are more expensive to treat than other minor health problems.
This doesn’t affect the argument. The author implies a comparison between the cost of treating early risk factors for mental disorders and the cost of treating more-fully-developed mental disorders, not between minor mental disorders and other, unrelated health problems.
B
Prevention research can be coordinated by drawing together geneticists, neurologists, and behavioral scientists.
This explains how the research program might be organized, not why it’s necessary to confirm the results of the existing research. It’s possible the previous research also included input from geneticists, neurologists, and behavioral scientists.
C
Reducing known risk factors for mental disorders is relatively inexpensive compared to the long-term treatment required.
This makes concrete the author’s main assumption, that treating risk factors early is more cost-effective than treating full-blown disorders later. It justifies her advocacy for funding in order to develop those treatments.
D
Current funding for intervention research is now higher than it has ever been before.
This compares past funding with present funding, while the author compares present funding with future funding. She argues funding should increase to support the program described—she makes no claim about the present level of research funding relative to past levels.
E
Once a mental disorder disappears, there is a fair chance that it will recur, given that complete cures are rare.
This doesn’t affect the argument. There’s no indication that current care practices or the ones to be developed will cause mental disorders to disappear—only that they might help prevent those disorders from developing.
Expert witness: Ten times, and in controlled circumstances, a single drop of the defendant’s blood was allowed to fall onto the fabric. And in all ten cases, the stained area was much less than the expected 9.5 cm2. In fact, the stained area was always between 4.5 and 4.8 cm2. I conclude that a single drop of the defendant’s blood stains much less than 9.5 cm2 of the fabric.
Summarize Argument: Phenomenon-Hypothesis
The expert witness presents the hypothesis that a single drop of the defendant’s blood stains much less than 9.5 cm2 of the fabric. This hypothesis is supported by an observation that, in each of ten controlled tests, a drop of the defendant’s blood stained a much smaller area—only 4.5 to 4.8 cm2.
Notable Assumptions
The expert witness assumes that the controlled conditions of the ten tests are relevantly similar to (presumably) the crime scene. In other words, the expert assumes that the defendant’s blood would not have stained a much larger area in different, more relevant conditions.
The expert also assumes that ten tests are a large enough sample size to know how much fabric will be stained by a drop of blood. In other words, the expert assumes that more tests would not have changed the results.
A
If similar results had been found after 100 test drops of the defendant’s blood, the evidence would be even stronger.
This does not weaken the expert’s argument. Just because the evidence would have been stronger with 100 tests, that doesn’t mean that ten tests were too few. This doesn’t undermine the adequacy of the expert’s observations.
B
Expert witnesses have sometimes been known to fudge their data to accord with the prosecution’s case.
This does not weaken the expert’s argument. Some experts sometimes fudging their data tells us nothing about this particular expert, nor the quality of the expert’s observations. Like (E), this is just a weak attempt at an ad hominem attack.
C
In an eleventh test drop of the defendant’s blood, the area stained was also less than 9.5 cm2—this time staining 9.3 cm2.
This weakens the expert’s argument because it suggests that the ten tests may not be a reliable sample of how much fabric the defendant’s blood stains. In other words, this undermines the expert’s assumption that ten tests are enough.
D
Another person’s blood was substituted, and in otherwise identical circumstances, stained between 9.8 and 10.6 cm2 of the fabric.
This does not weaken the expert’s argument, because the argument is only concerned with defendant’s blood behaves, not anyone else’s blood. If anything, this shows that the test is able to show if someone’s blood stains a larger area, and is therefore more reliable.
E
Not all expert witnesses are the authorities in their fields that they claim to be.
This does not weaken the expert’s argument. Like (B), this is an attempt at an ad hominem attack on the expert. However, just some experts not truly being authorities tells us nothing about this particular expert or this particular argument.
"Surprising" Phenomenon
Why did parliament vote to condemn the prime minister for promising aid to a plan most members of that parliament supported?
Objective
A hypothesis resolving this discrepancy must identify a reason for parliament to condemn its prime minister that does not rely on disagreement over the need for an intervention. Parliament must take issue with some aspect of the prime minister’s actions other than his support for the UN plan.
A
The UN Security Council cannot legally commit the military of a member nation to armed intervention in other countries.
This does not pertain to the situation described. It was the prime minister who promised military personnel, not the UN Security Council.
B
In the parliamentary leader’s nation, it is the constitutional prerogative of the parliament, not of the prime minister, to initiate foreign military action.
This is a reason for parliament to condemn the prime minister. If only parliament can promise military action, then they condemned the prime minister for exceeding his authority, not for supporting the UN plan.
C
The parliament would be responsible for providing the funding necessary in order to contribute military personnel to the UN intervention.
This does not account for parliament’s support for the intervention. Since parliament supports the UN plan, they would not object to the prime minister’s promise simply because funding the action is their own responsibility.
D
The public would not support the military action unless it was known that the parliament supported the action.
This does not account for the parliamentary leader’s statements. He states that parliament overwhelmingly supports the military action, so it is already known that parliament favors the plan, regardless of their vote.
E
Members of the parliament traditionally are more closely attuned to public sentiment, especially with regard to military action, than are prime ministers.
This does not explain the discrepancy between parliament’s support for the measure and their condemnation of the prime minister. Parliament and the prime minister support the intervention, regardless of public sentiment.