Before 1986 physicists believed they could describe the universe in terms of four universal forces. Experiments then suggested, however, a fifth universal force of mutual repulsion between particles of matter. This fifth force would explain the occurrence in the experiments of a smaller measurement of the gravitational attraction between bodies than the established theory predicted.

Summarize Argument: Phenomenon-Hypothesis
The author argues there’s a fifth universal force: mutual repulsion between particles of matter. This force would explain a phenomenon that the other four forces can’t explain on their own.

Notable Assumptions
While the fifth force would resolve one phenomenon, the scientist never tells us that the fifth force is consistent with other phenomena that the four forces already account for. The scientist therefore assumes that the fifth force is indeed compatible with other phenomena.

A
The extremely sophisticated equipment used for the experiments was not available to physicists before the 1970s.
This explains why scientists hadn’t considered the fifth force. We’re trying to strengthen the hypothesis that such a force exists.
B
No previously established scientific results are incompatible with the notion of a fifth universal force.
The fifth force doesn’t contradict settled science. If it did, the scientist couldn’t hypothesize that such a force exists.
C
Some scientists have suggested that the alleged fifth universal force is an aspect of gravity rather than being fundamental in itself.
This weakens the scientist’s hypothesis. The fifth force isn’t really a force at all—it’s an aspect of gravity.
D
The experiments were conducted by physicists in remote geological settings in which factors affecting the force of gravity could not be measured with any degree of precision.
This weakens the scientist’s hypothesis. The experiments, which the scientist uses as evidence, were undertaken in highly suboptimal circumstances
E
The fifth universal force was postulated at a time in which many other exciting and productive ideas in theoretical physics were developed.
We don’t care what else was happening in physics.

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Sandy: I play the Bigbucks lottery—that’s the one where you pick five numbers and all the players who have picked the five numbers drawn at the end of the week share the money pot. But it’s best to play only after there have been a few weeks with no winners, because the money pot increases each week that there is no winner.

Alex: No, you’re more likely to win the lottery when the money pot is small, because that’s when the fewest other people are playing.

Summarize Argument: Counter-Position
Alex implicitly concludes that Sandy should not play the Bigbucks lottery when the pot is larger. He supports this by saying Sandy is more likely to win when the pot is small, since that’s when the fewest people are playing.

Identify and Describe Flaw
Alex’s reasoning is mistaken because he doesn’t understand how the Bigbucks lottery works. To play, Sandy picks five numbers, and if they match the winning numbers, she shares the prize with anyone else who also picks correctly.

Alex thinks Sandy is more likely to win when fewer people play, but that’s not true. Her chance of picking the correct five numbers doesn't depend on how many other people are playing. The number of other players may affect how many people she’d have to split the pot with, but it doesn’t affect her individual chance of winning.

A
Sandy holds that the chances of anyone’s winning are unaffected by the number of times that person plays.
Like (C), Sandy never makes any claims about the chances of winning, nor does she claim that her chance of winning is unaffected by the number of times she plays. She just argues that it’s best to play when there’s a bigger pot.
B
Alex holds that the chances of Sandy’s winning are affected by the number of other people playing.
This describes a mistake in Alex’s reasoning. He thinks that Sandy is more likely to win when fewer people play. But actually, her chances of picking the correct five numbers are the same— extremely low— regardless of how many other players there are.
C
Sandy holds that the chances of anyone’s winning are unaffected by the size of the pot.
Like (A), Sandy never makes any claims about the chances of winning. Also, it’s true that the chances of anyone’s winning are unaffected by the size of the pot. So even if she did hold this, it wouldn’t be a mistake in her reasoning.
D
Alex holds that the chances of Sandy’s winning in a given week are unaffected by whether anyone has won the week before.
Alex never makes this claim. But even if he did, it wouldn’t describe a mistake in his reasoning because it’s true that Sandy’s chances of winning in a given week are unaffected by whether someone won the week before.
E
Sandy holds that the chances of there being a winner go up if no one has won the lottery for quite a while.
Sandy never claims that the chance of there being a winner goes up if no one has won in a while. She just argues that it’s best to play after no one has won in a while, because that’s when the pot is biggest.

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Columnist: George Orwell’s book 1984 has exercised much influence on a great number of this newspaper’s readers. One thousand readers were surveyed and asked to name the one book that had the most influence on their lives. The book chosen most often was the Bible; 1984 was second.

Summarize Argument

The author concludes that 1984 has had a great influence on the newspapers’ readers. This is because the second-most readers chose 1984 as the book that’d had the greatest influence on their lives.

Notable Assumptions

In order for 1984 to have exercised a great influence on the newspapers’s readers, the author assumes that 1984 received a substantial amount of votes. If the Bible had received 990 of the votes and 1984 had received 2, followed by an 8-way tie for third place, then the study wouldn’t demonstrate 1984’s great influence by any stretch.

A
How many books had each person surveyed read?

Irrelevant. We don’t care how many books each person read. We’re only interested in the ones the readers named as the book that most influenced their lives.

B
How many people chose books other than 1984?

If many people chose books other than 1984, then 1984 may not have received all that many votes (e.g if 500 books were chosen, 1984 might’ve only needed 10 votes to be 2nd place). If few people did, then 1984 might’ve received hundreds of votes (e.g. Bible 500, 1984 400, etc.).

C
How many people read the columnist’s newspaper?

We don’t care how many people read the newspaper. We know they surveyed 1000 people.

D
How many books by George Orwell other than 1984 were chosen?

We don’t care about other Orwell books. Even if those were chosen, we know those ranked lower than 1984.

E
How many of those surveyed had actually read the books they chose?

The author never claims people have read the books they cite as being influential on their own lives. The Bible may be influential on someone’s life even if that person hasn’t read it.


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Psychiatrist: We are learning that neurochemical imbalances can cause behavior ranging from extreme mental illness to less serious but irritating behavior such as obsessive fantasizing, petulance, or embarrassment. These findings will promote compassion and tolerance when looking at a mental illness, quirk, or mere difference between two persons, since being mentally healthy can now begin to be seen as simply having the same neurochemical balances as most people.

Summarize Argument

The psychiatrist predicts that recent findings about the neurochemical causes of behavioral issues will result in a more compassionate, tolerant view of things like mental illness and behavioral differences. Why the kinder view? Because people can start to view the idea of “mental health” as really just a certain neurochemical balance that happens to be more common.

Identify Conclusion

The psychiatrist’s conclusion is his prediction: “These findings [about neurochemical balances being a cause of mental illness and other issues] will promote compassion and tolerance when looking at a mental illness, quirk, or mere difference between two persons.”

A
Understanding the role of the neurochemical in behavior will foster empathy toward others.

This paraphrases the psychiatrist’s conclusion: knowledge about how neurochemical imbalances affect behavior will “promote compassion and tolerance” or “foster empathy” toward those with mental health or behavioral issues.

B
Neurochemical imbalances can cause mental illness and other behaviors.

The psychiatrist uses this fact as context. His conclusion is that this fact will produce a certain effect: it will promote compassion and tolerance toward those with mental health or behavioral issues.

C
Neurochemical balances and imbalances are the main determinants of mental behavior.

The psychiatrist never suggests what the main determinant of mental behavior is. He merely states that neurochemical balances and imbalances are one potential determinant.

D
Being mentally healthy is a matter of having the same neurochemical balances as most people.

The psychiatrist states that mental health can be viewed this way, but this forms his premise, not his conclusion. The fact that mental health can be seen in this light leads him to conclude that people will become more tolerant of mental health and behavioral issues.

E
Advances in neurochemistry enhance our theories of mental illness.

The psychiatrist doesn’t reach any conclusions about theories of mental illness. He presents findings about a possible cause of mental illness, and concludes that those findings will affect people’s attitudes.


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Sociologist: The welfare state cannot be successfully implemented because it rests on the assumption that human beings are unselfish—a seemingly false assumption. The welfare state is feasible only if wage earners are prepared to have their hard-earned funds used to help others in greater need, and that requires an unselfish attitude. But people innately seek their own well-being, especially when the interests of others threaten it.

Summarize Argument
The author claims that the welfare state is not feasible. They explain this claim by saying that the welfare state rests on the false assumption that people are unselfish. We know that the welfare state rests on this assumption because it can only work if wage-earners will let their money be used to help those who need it more, which requires unselfishness. We know that the assumption of unselfishness is false because people innately focus on their own benefit, especially when that benefit is threatened by other people’s interests.

Identify Conclusion
The conclusion is the author’s assertion that the welfare state won’t work: “The welfare state cannot be successfully implemented.”

A
The welfare state will not work.
This accurately paraphrases the conclusion. Everything else in the argument supports the claim that the welfare state “cannot be successfully implemented,” meaning that it won’t work.
B
The welfare state unfairly asks those who work hard to help those in greater need.
The author does not claim that it is unfair to ask hard-working people to help others in greater need. According to the author, people may not want to help, but fairness is never mentioned.
C
The assumption that human beings are unselfish is false.
This is a sub-conclusion or major premise in the argument, not the main conclusion. This claim is supported by the statement that “people innately seek their own well-being”, but in turn this claim supports the main conclusion that the welfare state is not viable.
D
The interests of the less fortunate impinge on the interests of others.
This is not a claim the argument supports. The suggestion that some people’s interests may threaten other people’s interests emphasizes the claim that people are not selfish, but is not supported by anything else.
E
The welfare state relies on the generosity of wage earners.
This claim is not supported by the rest of the argument. Instead, it supports the idea that the welfare state requires people to be unselfish, which helps lead to the main conclusion.

102 comments