To the Editor: In 1960, an astronomer proposed a mathematical model for determining whether extraterrestrial life exi...

Alix-Hirsh on January 9, 2019


Hi! Can you please explain why E is incorrect.

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Kanyin on July 5, 2019

Yes, would appreciate an explainer on the difference between c and e

Ravi on July 23, 2019

@Alix-Hirsh and @Kanyin,

Happy to help.

In the argument, Mr. Moltz doesn't look to be thinking the arguments
supporting alien life are good. There are supposedly many stars and
planets in space that could support alien life, but based on Moltz's
facts, astronomers have not detected a single one of these planets
outside of our solar system. He then concludes that no detected planet
means no alien life, which means that life only exists here on Earth.

Moltz's strongest evidence for the lack of alien life is that
astronomers have failed to discover any planets outside of our solar
system. However, even if astronomers haven't detected any other
planets, this doesn't mean that those planets do not exist. It's
possible that we simply haven't found these planets yet. Because this
is a weaken question, we are likely looking for something that draws
evidence to the logical fallacy present in Moltz's argument (that a
lack of evidence is proof that something doesn't exist).

Let's take a look at (C) and (E).

(C) says, "Detecting planets outside our solar system requires more
sophisticated instruments than are currently available."

(C) does a great job at pointing out the flaw in Moltz's argument
(that a lack of evidence proves that something doesn't exist). Just
because we have not yet found planets outside of our solar system does
not mean that they do not exist. If we do not yet have sophisticated
enough instruments to detect them, it's possible that they're actually
out there. (C) works by suggesting that Clay's evidence is irrelevant
to his conclusion. Thus, (C) is the correct answer choice.

(E) says, "Due to sheer distances and expanses of space involved, any
extraterrestrial civilization would have great difficulty
communicating with ours."

In reading the stimulus, we see that the question at hand is about the
existence of aliens. It is not about whether or not humans can
communicate with them. While this topic could be relevant to a similar
question, communication with extraterrestrial civilizations—or a lack
thereof—will not really tell us about whether or not those
civilizations exist. Thus, we can get rid of (E).

Does this make sense? Let us know if you have any more questions!

jjchoi793 on September 1, 2019

Hi! Could you help me answer why (D) is wrong and what exactly the answer is saying. Thank you!

Ravi on September 9, 2019


Let's take a look at (D).

(D) says, "The soundness of the conclusion reached by applying a
mathematical model depends on the soundness of the assumptions on
which the model is based."

The topics (D) discusses, math and assumptions, are definitely
relevant to the astronomer's argument. However, the problem with (D)
is that Clay's conclusion isn't reached by applying a mathematical
model. Therefore, (D) doesn't weaken Clay's conclusion, so we can get
rid of this answer choice.

Hope this helps. Let us know if you have any other questions!