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- Tue Jun 27, 2017 12:49 pm
#36427
Complete Question Explanation
Flaw in the Reasoning—#%. The correct answer choice is (C)
The argument has a complex structure, featuring two premises and a sub-conclusion that is then used
to support the main conclusion of the argument:
Premise: According to some astronomers, Earth is struck by a meteorite large
enough to cause an ice age on an average of once every 100 million
years.
Premise: The last such incident occurred nearly 100 million years ago,
Sub-conclusion: so we can expect that Earth will be struck by such a meteorite in the
near future.
Main Conclusion: This clearly warrants funding to determine whether there is a means to
protect our planet from such meteorite strikes.
Do the supporting statements prove the main conclusion? Again, personalize the argument—does
it make sense that if the earth has been struck “on an average of once every 100 million years” that
suddenly we are in imminent danger? Of course not. The problem is that historical averages are only
averages, and you cannot predict that a meteorite strike is overdue or likely based on such averages.
The reasoning in the argument is made even weaker when you consider the scale of time involved.
Even if the historical pattern holds on average, a million or two million year variation would be a
very small deviation compared to 100 million years, so it makes absolutely no sense to conclude that
there will defi nitely be a meteorite strike in the “near future.” And, of course, if there is no certainty
that earth will be struck in the near future, how can funding be “clearly warranted?”
Answer choice (A): This choice was commonly selected, but there is no justifi cation for this answer.
The fi rst section of the answer—“makes a bold prescription”—does occur in the reasoning. However,
the second part—“on the basis of evidence that establishes only a high probability for a disastrous
event”—does not occur because the stimulus does not establish a high probability for a disastrous
event.
Of course, even if you saw the stimulus as establishing a high probability for disaster, wouldn’t that
high probability of disaster actually be a good justifi cation for a “bold prescription?” Probably so,
and thus it is hard to see how this choice would actually describes a fl aw even if everything described
within it had occurred.
Answer choice (B): The argument presumes precisely the opposite of this choice because the author
believes that the probability of a chance event—the meteorite—is affected by whether or not it has
happened recently. In the stimulus, the author makes clear that she believes that there is a greater
likelihood of a meteorite strike today because there has not been a meteorite strike recently.
Furthermore, this choice describes reasoning that is often sound, as opposed to unsound, reasoning.
Typically, a chance event is not affected by preceding events or whether there has been a recent
occurrence of that event, and that is what is described in this answer. The reasoning in the stimulus,
on the other hand, implies that for chance events, the past affects the future. Believing the stimulus is
similar to a gambler believing that since he has thrown snake-eyes on average every third roll, it will
keep happening every third roll. Historical averages, without some other supporting data, are prone
to misrepresentation and misinterpretation, and should not be assumed to repeat.
Answer choice (C): This is the correct answer choice. Both parts of the answer occur, and what is
described is a fl aw:
“moves from evidence about the average frequency of an event”—this section describes the
fact that a large meteorite strikes earth on an average of once every 100 million years.
“to a specifi c prediction about when the next such event will occur”—this section describes
the sub-conclusion that “we can expect that Earth will be struck by such a meteorite
in the near future.”
An average cannot be used to make a specifi c prediction, and therein lies the fl aw.
Answer choice (D): This choice could be relevant to whether investing in preventing a strike makes
good public policy; however, it does not address the main fl aw in the argument. Furthermore, even
if the likelihood of an ice age resulting from a strike is very low, there could be other effects such as
the destruction of cities that would suggest meteorite strike prevention as valuable, so the issue of ice
ages is not critical.
Answer choice (E): The argument does not make any presumption that preventing large strikes is
feasible, it only suggests that we begin investigations into protecting Earth.
Flaw in the Reasoning—#%. The correct answer choice is (C)
The argument has a complex structure, featuring two premises and a sub-conclusion that is then used
to support the main conclusion of the argument:
Premise: According to some astronomers, Earth is struck by a meteorite large enough to cause an ice age on an average of once every 100 million years. Premise: The last such incident occurred nearly 100 million years ago, Sub-conclusion: so we can expect that Earth will be struck by such a meteorite in the near future. Main Conclusion: This clearly warrants funding to determine whether there is a means to protect our planet from such meteorite strikes.Do the supporting statements prove the main conclusion? Again, personalize the argument—does
it make sense that if the earth has been struck “on an average of once every 100 million years” that
suddenly we are in imminent danger? Of course not. The problem is that historical averages are only
averages, and you cannot predict that a meteorite strike is overdue or likely based on such averages.
The reasoning in the argument is made even weaker when you consider the scale of time involved.
Even if the historical pattern holds on average, a million or two million year variation would be a
very small deviation compared to 100 million years, so it makes absolutely no sense to conclude that
there will defi nitely be a meteorite strike in the “near future.” And, of course, if there is no certainty
that earth will be struck in the near future, how can funding be “clearly warranted?”
Answer choice (A): This choice was commonly selected, but there is no justifi cation for this answer.
The fi rst section of the answer—“makes a bold prescription”—does occur in the reasoning. However,
the second part—“on the basis of evidence that establishes only a high probability for a disastrous
event”—does not occur because the stimulus does not establish a high probability for a disastrous
event.
Of course, even if you saw the stimulus as establishing a high probability for disaster, wouldn’t that
high probability of disaster actually be a good justifi cation for a “bold prescription?” Probably so,
and thus it is hard to see how this choice would actually describes a fl aw even if everything described
within it had occurred.
Answer choice (B): The argument presumes precisely the opposite of this choice because the author
believes that the probability of a chance event—the meteorite—is affected by whether or not it has
happened recently. In the stimulus, the author makes clear that she believes that there is a greater
likelihood of a meteorite strike today because there has not been a meteorite strike recently.
Furthermore, this choice describes reasoning that is often sound, as opposed to unsound, reasoning.
Typically, a chance event is not affected by preceding events or whether there has been a recent
occurrence of that event, and that is what is described in this answer. The reasoning in the stimulus,
on the other hand, implies that for chance events, the past affects the future. Believing the stimulus is
similar to a gambler believing that since he has thrown snake-eyes on average every third roll, it will
keep happening every third roll. Historical averages, without some other supporting data, are prone
to misrepresentation and misinterpretation, and should not be assumed to repeat.
Answer choice (C): This is the correct answer choice. Both parts of the answer occur, and what is
described is a fl aw:
“moves from evidence about the average frequency of an event”—this section describes the fact that a large meteorite strikes earth on an average of once every 100 million years. “to a specifi c prediction about when the next such event will occur”—this section describes the sub-conclusion that “we can expect that Earth will be struck by such a meteorite in the near future.”An average cannot be used to make a specifi c prediction, and therein lies the fl aw.
Answer choice (D): This choice could be relevant to whether investing in preventing a strike makes
good public policy; however, it does not address the main fl aw in the argument. Furthermore, even
if the likelihood of an ice age resulting from a strike is very low, there could be other effects such as
the destruction of cities that would suggest meteorite strike prevention as valuable, so the issue of ice
ages is not critical.
Answer choice (E): The argument does not make any presumption that preventing large strikes is
feasible, it only suggests that we begin investigations into protecting Earth.
