Summarize Argument
The author concludes that Dalton can’t be a member of Sutherlin, Pérez, and Associates, because his primary specialization is in divorce cases, while the firm’s is in criminal defense cases.
Identify and Describe Flaw
This is the cookie-cutter “confusing whole vs. part” flaw, otherwise known as the fallacy of division. The author assumes that, because something is true of a group as a whole, it must also be true for one part or member of that group. In other words, he assumes that, just because the firm specializes in criminal defense and Dalton does not specialize in criminal defense, Dalton cannot be a member of the firm.
A
offers in support of its conclusion pieces of evidence that are mutually contradictory
This is the cookie-cutter flaw of “internal contradiction,” where an argument contradicts itself. The author’s argument simply doesn’t make this mistake. His evidence may not support his conclusion very well, but it isn’t contradictory.
B
overlooks the possibility that a person can practice law without being a member of a law firm
This wouldn’t damage the argument, so overlooking it can’t be a flaw. The author only argues that Dalton isn’t a part of this particular firm. Whether he’s part of a different firm or no firm at all would not impact this argument.
C
concludes that someone is not a member of a group on the grounds that that person does not have a characteristic that the group as a whole has
The author concludes that Dalton isn’t a member of Sutherlin, Pérez, and Associates on the grounds that the group as a whole specializes in criminal defense, while Dalton does not.
D
takes a high rate of success among the members of a group to indicate that the successes are evenly spread among the members
The author claims that the firm is one of the most successful, but he never makes the claim that each member of the firm is equally successful.
E
states a generalization based on a selection that is not representative of the group about which the generalization is supposed to hold true
The author’s conclusion is not a generalization, it’s a specific statement about Dalton.
Summarize Argument: Phenomenon-Hypothesis
The author poses the hypothesis that triple-trailer trucks, which are not currently allowed on national highways, are actually safer than other commercial vehicles. This hypothesis is based on an observation from the western part of the country, where triple-trailers are allowed on highways. In those areas, the traffic fatality rate for triple-trailers is lower than the national traffic fatality rates for other commercial vehicles.
Notable Assumptions
The author assumes that the triple-trailer fatality rate from the West would be equivalent to the rate across the country as a whole. This is shown by comparing triple-trailer rates from only one area to other commercial vehicles’ national rates.
The author also assumes that vehicles’ safety is accurately represented by those vehicles’ traffic fatality rates alone, and not, for example, injury rates.
The author also assumes that vehicles’ safety is accurately represented by those vehicles’ traffic fatality rates alone, and not, for example, injury rates.
A
It takes two smaller semitrailers to haul as much weight as a single triple-trailer can.
This does not weaken the argument. The amount of cargo that different types of vehicles can haul has no bearing on how we assess the safety of those vehicles. This claim is just irrelevant to the argument.
B
Highways in the sparsely populated West are much less heavily traveled and consequently are far safer than highways in the national system as a whole.
This weakens the argument by undermining the author’s comparison of triple-trailer fatality rates from the West against other vehicles’ national rates. This claim undermines the conclusion that triple-trailers are overall safer—instead, they’re just being driven in safer areas.
C
Opponents of the triple-trailers also once opposed the shorter twin-trailers, which are now common on the nation’s highways.
This does not weaken the argument. Whatever else the opponents have ever opposed is totally irrelevant to how safe triple-trailers are. Even if we knew how safe twin-trailers are, which we don’t, this wouldn’t do anything to the argument.
D
In areas where the triple-trailers are permitted, drivers need a special license to operate them.
This does not weaken the argument. If anything, this could strengthen by providing a mechanism for triple-trailers’ safety. We don’t know whether other commercial vehicle drivers also need special licenses, though, so it’s hard to compare. Either way, no weakening here!
E
For triple-trailers the rate of road accident fatalities per mile of travel was higher last year than in the two previous years.
This does not weaken the argument. How triple-trailer fatality rates have changed over the last few years tells us nothing without more information. How big was the change? Do we know what caused it? We don’t know. As it is, this is just irrelevant to the argument.
Summarize Argument
The author concludes that law-abiding people are solely responsible for crime. This is based on the assertions that (1) criminal actions, like all actions, are products of the environment, and (2) law-abiding people do the most to create and maintain the environment.
Identify and Describe Flaw
The author’s conclusion contradicts parts of the reasoning. The author uses as a premise the claim that all actions are products of the environment. Because this means criminals’ actions are products of the environment, the author believes criminals are not responsible for their crimes. But law-abiding persons’ actions that create the environment would also be products of the environment, and thus they should not be responsible for their actions, either. The conclusion, however, asserts law-abiding people are responsible for crime.
A
it exploits an ambiguity in the term “environment” by treating two different meanings of the word as though they were equivalent
The author does not shift between multiple meanings of “environment.” “Environment” throughout the stimulus refers to the surroundings, conditions, and circumstances of a person’s life.
B
it fails to distinguish between actions that are socially acceptable and actions that are socially unacceptable
The stimulus concerns responsibility for crime. The distinction between socially acceptable and socially unacceptable plays no role in the reasoning. Even if you believe crime is socially unacceptable, the author does not fail to distinguish between crime and law-abiding actions.
C
the way it distinguishes criminals from crimes implicitly denies that someone becomes a criminal solely in virtue of having committed a crime
The argument does not deny that one becomes a “criminal” solely by committing a crime. There’s a difference between what gives someone the status of “criminal” (which is what (C) is about) and what causal factors lead one to commit crimes (which is what the stimulus is about).
D
its conclusion is a generalization of statistical evidence drawn from only a small minority of the population
There is no statistical evidence presented. And, the conclusion is not a generalization from what’s true about a small minority of the population.
E
its conclusion contradicts an implicit principle on which an earlier part of the argument is based
In denying the responsibility of criminals, the author uses the implicit principle that one is not responsible for actions that are a product of one’s environment. But the author contradicts this principle when claiming that law-abiding persons are responsible for crime.