Critical Reasoning

The greatest chance for the existence of extraterrestrial life is on a planet beyond our solar system. The Milky Way galaxy alone contains 100 billion other suns, many of which could be accompanied by planets similar enough to Earth to make them suitable abodes of life.

The statement above assumes which of the following?

A. Live creatures on another planet would probably have the same appearance as those on Earth.
B. Live cannot exist on other planets in our solar system.
C. If the appropriate physical conditions exist, life is an inevitable consequence.
D. More than one of the suns in tha galaxy is accompanied by an Earth-like planet.
E. It is likely that life on another planet would require conditions similar to those on Earth.

IOM : E, anyone has any other suggestions? If so, why E is not correct?
This is a little out of the scope: why in "D" the author uses "is" instead of "are", is "more than one of the suns" singular?
[spoiler]OA: C[/spoiler]

The correct answer cannot be choice C. What is the source? Even if it is an official source, exactly where did you get this question from? Somewhere on the internet? There had to have been a transcription error.

Also, the question stem is flawed. As the author has made more than a single statement and as an "assumption" is not a necessary component of an argument, the question stem should have read:

"The argument above assumes which of the following?"

Your reasoning is correct: the correct answer is choice E. The author argues that the greatest chances of finding extraterrestial life is outside the solar system because there are more Earth-like planets outside of the solar system than inside. Thus, the author is assuming that "it is likely that life on another planet would require conditions similar to those on Earth." (Notice the match-up between "greatest chances" and "it is likely.")

We can use the Kaplan denial test to confirm. The denial of choice E is:

It is likely that life on another planet would require conditions DIS-similar to those on Earth. In that case, the argument falls apart. Thus, the argument depends on choice E.

Thank Testluv so much. I got this question from a friend, who is attending a private tutoring class. It made me confuse as I did not know why E is not correct. However, can you please explain in more detail why C is incorrect? Will appreciate so much if you can help.

Choice C is outside the scope of the argument. Notice that the argument's reasoning involved similarity to Earth (and that choice E falls squarely within this scope). But the argument never ever discussed what physical conditions are appropriate to life or that certain physical conditions were more or less appropriate.

Also, choice C is extreme ("inevitable consequences").

Testluv wrote:The correct answer cannot be choice C. What is the source? Even if it is an official source, exactly where did you get this question from? Somewhere on the internet? There had to have been a transcription error.

Also, the question stem is flawed. As the author has made more than a single statement and as an "assumption" is not a necessary component of an argument, the question stem should have read:

"The argument above assumes which of the following?"

Your reasoning is correct: the correct answer is choice E. The author argues that the greatest chances of finding extraterrestial life is outside the solar system because there are more Earth-like planets outside of the solar system than inside. Thus, the author is assuming that "it is likely that life on another planet would require conditions similar to those on Earth." (Notice the match-up between "greatest chances" and "it is likely.")

We can use the Kaplan denial test to confirm. The denial of choice E is:

It is likely that life on another planet would require conditions DIS-similar to those on Earth. In that case, the argument falls apart. Thus, the argument depends on choice E.

Could you explain why B is incorrect? I must admit that the language is strong , but if the author argued that " the greatest chance....solar system", isnt the author assuming that life cannot exist in our solar system?

The author is arguing that the greatest chances of finding extraterrestial life are outside the solar system. This doesn't mean he thinks the chances of finding life in the solar system are zero--just slim.

I agree that answer should be E. No way C can be the answer.