The Question Stem reads: The lawyer's conclusion follows logically if which one of the following is assumed? This is a Sufficient Assumption question.

The lawyer begins by describing how this witness was present at the restaurant when the lawyer's famous client was assaulted. However, the witness claims to recognize the assailant but not the famous client. The lawyer concludes the witness's testimony should be excluded. We can break down the argument to read:

P1: Witness claims to recognize the assailant

P2: Witness claims not to recognize the victim (Famous client)

________________

C: Exclude witness testimony

In the CC, we discussed that elements of the conclusion must be in the premises. Nowhere in the premises do we see a claim about what kind of testimony should not be included. We need a conditional that brings us to "exclude testimony," so let's make that our necessary condition: (__) -> Exclude testimony.

Now it will be hard to anticipate what sufficient condition the AC will use. They could use P1 or P2 or some combination of both. When we screen these answer choices, the first order of business will be to make sure that the necessary condition is: "exclude testimony" Then we will check the sufficient condition to ensure it gets triggered by the information in the stimulus. Let's go.

Answer Choice (A) has the necessary condition "then the witness's testimony should be included." Without looking at the rest of the (A), we can eliminate it because it takes us to "include" when we want to go to "exclude." If you picked (A), you likely assumed that "claims recognize both parties -> include" implied that "/(claims recognize both parties) -> exclude," which is a logical fallacy. Remember: a->b does not imply /a->/b.

Answer Choice (B) is arbitrary. Why would the fact that other witnesses can identify the client mean we should exclude the witness from the stimulus? Nothing. Eliminate and move on.

Answer Choice (C) is also arbitrary because it does not bring us to a conclusion "exclude testimony." As a side note, whether or not we can know if the witness actually recognized the assailant is irrelevant. Notice how the premises only take into account who the victim claims to recognize. The lawyer's argument is going to rely on the witness's claims, not what actually is the case.

Correct Answer Choice (D) gets us to where we need to go. If we take the contrapositive of (D), we get: "/(claims to recognize both parties in assault) -> exclude." The necessary condition is exactly what we discussed. The sufficient condition is great. The witness did not claim to recognize both parties in the assault. The witness claims to recognize only the assailant. So the conditional triggers and delivers us to the conclusion that the witness's testimony should be excluded.

Answer Choice (E) is a popular wrong answer. If you picked (E), you likely inferred that the witness was lying about not recognizing the famous victim. First, that is not an inference you can make. Just because it is unlikely that someone wouldn't recognize the famous client, that does not mean it is impossible that someone would fail to recognize the client. Second, even if we could infer that the witness was lying, it wouldn't help us. What does lying have to do with excluding testimony? If you answered that "liars testimony should be excluded," you've proved that (E) by itself is insufficient to draw the lawyer's argument.


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The Question Stem reads: The lawyer's conclusion follows logically if which one of the following is assumed? This is a Sufficient Assumption question.

The lawyer begins by describing how this witness was present at the restaurant when the lawyer's famous client was assaulted. However, the witness claims to recognize the assailant but not the famous client. The lawyer concludes the witness's testimony should be excluded. We can break down the argument to read:

P1: Witness claims to recognize the assailant

P2: Witness claims not to recognize the victim (Famous client)

________________

C: Exclude witness testimony

In the CC, we discussed that elements of the conclusion must be in the premises. Nowhere in the premises do we see a claim about what kind of testimony should not be included. We need a conditional that brings us to "exclude testimony," so let's make that our necessary condition: (__) -> Exclude testimony.

Now it will be hard to anticipate what sufficient condition the AC will use. They could use P1 or P2 or some combination of both. When we screen these answer choices, the first order of business will be to make sure that the necessary condition is: "exclude testimony" Then we will check the sufficient condition to ensure it gets triggered by the information in the stimulus. Let's go.

Answer Choice (A) has the necessary condition "then the witness's testimony should be included." Without looking at the rest of the (A), we can eliminate it because it takes us to "include" when we want to go to "exclude." If you picked (A), you likely assumed that "claims recognize both parties -> include" implied that "/(claims recognize both parties) -> exclude," which is a logical fallacy. Remember: a->b does not imply /a->/b.

Answer Choice (B) is arbitrary. Why would the fact that other witnesses can identify the client mean we should exclude the witness from the stimulus? Nothing. Eliminate and move on.

Answer Choice (C) is also arbitrary because it does not bring us to a conclusion "exclude testimony." As a side note, whether or not we can know if the witness actually recognized the assailant is irrelevant. Notice how the premises only take into account who the victim claims to recognize. The lawyer's argument is going to rely on the witness's claims, not what actually is the case.

Correct Answer Choice (D) gets us to where we need to go. If we take the contrapositive of (D), we get: "/(claims to recognize both parties in assault) -> exclude." The necessary condition is exactly what we discussed. The sufficient condition is great. The witness did not claim to recognize both parties in the assault. The witness claims to recognize only the assailant. So the conditional triggers and delivers us to the conclusion that the witness's testimony should be excluded.

Answer Choice (E) is a popular wrong answer. If you picked (E), you likely inferred that the witness was lying about not recognizing the famous victim. First, that is not an inference you can make. Just because it is unlikely that someone wouldn't recognize the famous client, that does not mean it is impossible that someone would fail to recognize the client. Second, even if we could infer that the witness was lying, it wouldn't help us. What does lying have to do with excluding testimony? If you answered that "liars testimony should be excluded," you've proved that (E) by itself is insufficient to draw the lawyer's argument.


11 comments

Unlike many machines that are perfectly useful in isolation from others, fax machines must work with other fax machines. Thus, in the fax industry, the proliferation of incompatible formats, which resulted from the large number of competing manufacturers, severely limited the usefulness—and hence the commercial viability—of fax technology until the manufacturers agreed to adopt a common format for their machines.

Summary
Fax machines are only useful with other fax machines. The proliferation of incompatible formats from manufacturer to manufacturer severely limits the usefulness of fax machines. This occurred until manufacturers standardized a common format for their fax machines.

Strongly Supported Conclusions
In some industries it is better for competitors to cooperate with each other in some circumstances.

A
Whenever machines are dependent on other machines of the same type, competition among manufacturers is damaging to the industry.
This answer is unsupported. The stimulus is limited to fax machines as an example. We don’t know anything about machines in any other industry.
B
In some industries it is in the interest of competitors to cooperate to some extent with one another.
This answer is strongly supported. If fax machines must work with other fax machines, then it is in the interest of different fax machine manufacturers to cooperate to some extent.
C
The more competitors there are in a high-tech industry, the more they will have to cooperate in determining the basic design of their product.
This answer is unsupported. The stimulus is limited to the fax industry, and we have no information in the stimulus whether this is a high-tech industry.
D
Some cooperation among manufacturers in the same industry is more beneficial than is pure competition.
This answer is unsupported. We don’t know from the stimulus what the benefits are, if any, of a scenario of pure competition to make this comparison.
E
Cooperation is beneficial only in industries whose products depend on other products of the same type.
This answer is unsupported. Saying cooperation is only beneficial in these types of industries is too strong.

12 comments

Albert: The government has proposed new automobile emissions regulations designed to decrease the amount of polycyclic aromatic hydrocarbons (PAHs) released into the atmosphere by automobile exhaust. I don’t see the need for such regulations; although PAHs are suspected of causing cancer, a causal link has never been proven.

Erin: Scientists also blame PAHs for 10,000 premature deaths in this country each year from lung and heart disease. So the proposed regulations would save thousands of lives.

Summarize Argument
Erin concludes that the proposed regulation decreasing PAH emissions from automobile exhaust would save thousands of lives. This is because scientists blame PAHs for many premature deaths from lung and heart disease.

Notable Assumptions
Erin assumes that the same problem Albert notes in his argument—that no causal link between PAHs and cancer have been proven—isn’t relevant to the diseases she mentions. This means she either thinks that there is a causal link between PAHs and lung and heart disease, or that it’s unimportant to establish such a link when scientists blame several major health problems on PAHs.

A
Most automobile manufacturers are strongly opposed to additional automobile emissions regulations.
We can imagine automobile manufacturers don’t like regulations. But we’re not interested in what they like or don’t like. We need to know about the link between PAHs from automobile emissions and various diseases.
B
It is not known whether PAHs are a causal factor in any diseases other than heart and lung disease and cancer.
We don’t know if PAHs are a causal factor in heart and lung disease and cancer. This just tells us that other diseases fall into the same “unknown” category.
C
Even if no new automobile emissions regulations are enacted, the amount of PAHs released into the atmosphere will decrease if automobile usage declines.
There would still be a benefit to regulating PAHs further, given their link to diseases. Thus, this doesn’t weaken the notion that PAHs should be regulated.
D
Most of the PAHs released into the atmosphere are the result of wear and tear on automobile tires.
Even if PAHs from automobile exhaust were banned, the majority of current PAH production would continue through wear and tear on automobile tires. Thus, the regulation wouldn’t in fact save “thousands of lives.”
E
PAHs are one of several components of automobile exhaust that scientists suspect of causing cancer.
This doesn’t tell us that PAHs constitute only a small or insignificant fraction of the carcinogenic effects of automobile exhaust, so we can’t assume Erin would be wrong about the regulation. Banning PAHs may still save thousands of lives.

16 comments

Helen: Reading a book is the intellectual equivalent of investing money: you’re investing time, thereby foregoing other ways of spending that time, in the hope that what you learn will later afford you more opportunities than you’d get by spending the time doing something other than reading that book.

Randi: But that applies only to vocational books. Reading fiction is like watching a sitcom: it’s just wasted time.

Summarize Argument: Counter-Position
Randi concludes that reading books is only an intellectual investment if those books are vocational. This qualifies Helen’s general claim that reading a book in hopes that it will lead to gains later on makes reading similar to investing money. To support this qualification, Randi says that reading fiction is a waste of time, comparable to watching sitcoms.

Describe Method of Reasoning
Randi argues that Helen’s analogy cannot be accurately drawn between two kinds of action, because not all the instances of one action are analogous to the other action. By claiming that reading fiction is analogous to watching a sitcom instead of to financial investment, Randi undermines the strength of Helen’s general analogy between book-reading and investment.

A
questioning how the evidence Helen uses for a claim was gathered
Randi does not question Helen’s evidence-gathering, only her theoretical reasoning. In fact, neither Helen nor Randi really presents gathered evidence at all.
B
disputing the scope of Helen’s analogy by presenting another analogy
By presenting an analogy between reading fiction and watching sitcoms, Randi claims that only reading certain (vocational) books can be compared to investing. This is how Randi disputes the scope of Helen’s analogy between reading and investing.
C
arguing that Helen’s reasoning ultimately leads to an absurd conclusion
Randi does not argue that Helen’s reasoning leads to an absurd conclusion, only that Helen’s reasoning is flawed because Helen’s analogy is too broad.
D
drawing an analogy to an example presented by Helen
Randi does not draw an analogy to an example presented by Helen. Randi only analogizes to a new example: watching sitcoms.
E
denying the relevance of an example presented by Helen
Randi does not deny the relevance of any part of Helen’s argument, just claims that its scope is too general.

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