Some people believe there is intelligent life somewhere in the univers

Question

Some people believe there is intelligent life somewhere in the universe besides Earth. But no one who believes that could also believe all planets other than Earth are devoid of life. Thus, some people do not believe all planets other than Earth are devoid of life.

The reasoning in which one of the following is most similar to the reasoning in the argument above?

(A) Some people believe computers are capable of thought. Since no one who does not believe computer chess programs sometimes beat human chess masters believes computers can think, it follows that computer chess programs do sometimes beat human chess masters.

(B) Some cat owners believe cats are incapable of feeling guilty. Since one could think that an animal is capable of feeling guilty only if one thought the animal had a conception of morality, it follows that some cat owners do not believe cats have a conception of morality.

(C) Some dog owners believe their dogs are emotionally attached to them. Since no one could believe that and also believe dogs are incapable of thought, it follows that some dog owners do not believe dogs are incapable of thought.

(D) Some people believe humans will someday colonize other planets. Since anyone who believes that probably also believes overpopulation of Earth is not a problem, it follows that some people do not believe overpopulation of Earth is not a problem.

(E) Some people believe there is life on planets other than Earth. Since anyone who believes that must also believe other planets have atmospheres that can support life, it follows that other planets do have atmospheres that can support life.

ankushsambare · Answer

Premises
 
 Some people believe: intelligent life exists elsewhere in the universe. 
 No one who believes that can also believe: all other planets are devoid of life.  
Conclusion
 
 Therefore, some people do not believe all other planets are devoid of life.  
Prethinking
Structure: Some people believe A. A is incompatible with belief B. Therefore, some people do not believe B.
Check options
A: Different structure 
B: Not same logic form 
C: Some believe A; A incompatible with B; therefore some do not believe B matches
D: Uses probability (“probably”) 
E: Wrong conclusion strength
Answer: C

guddo · Answer

Some people believe there is intelligent life somewhere in the universe besides Earth. But no one who believes that could also believe all planets other than Earth are devoid of life. Thus, some people do not believe all planets other than Earth are devoid of life.
 
 The reasoning in which one of the following is most similar to the reasoning in the argument above?

The original argument has this structure: some people believe X. Anyone who believes X cannot also believe Y. Therefore, some people do not believe Y.  The argument is about incompatible beliefs , not about what is actually true in the world.

(A) Some people believe computers are capable of thought. Since no one who does not believe computer chess programs sometimes beat human chess masters believes computers can think, it follows that computer chess programs do sometimes beat human chess masters.

Wrong. This moves from people’s beliefs to a factual conclusion about computer chess programs. The original argument concludes only what some people do not believe.

(B) Some cat owners believe cats are incapable of feeling guilty. Since one could think that an animal is capable of feeling guilty only if one thought the animal had a conception of morality, it follows that some cat owners do not believe cats have a conception of morality.

Wrong. The structure is different. The premise is about people who believe cats are incapable of guilt, but the conditional is about people who believe an animal is capable of guilt.

(C) Some dog owners believe their dogs are emotionally attached to them. Since no one could believe that and also believe dogs are incapable of thought, it follows that some dog owners do not believe dogs are incapable of thought.

Correct. This matches exactly: some people believe X; no one who believes X can also believe Y; therefore, some people do not believe Y. Here, X is that dogs are emotionally attached, and Y is that dogs are incapable of thought.

(D) Some people believe humans will someday colonize other planets. Since anyone who believes that probably also believes overpopulation of Earth is not a problem, it follows that some people do not believe overpopulation of Earth is not a problem.

Wrong. “Probably” makes the logic weaker, and the relationship is not one of  incompatible beliefs .

(E) Some people believe there is life on planets other than Earth. Since anyone who believes that must also believe other planets have atmospheres that can support life, it follows that other planets do have atmospheres that can support life.

Wrong. This again moves from belief to fact. The original argument does not conclude that life actually exists elsewhere; it concludes only that some people do not believe a certain claim.

Answer: (C)

yc168 · Answer

OE for reference:

Overview:  
The argument indicates that some people have a certain belief (that there is intelligent life somewhere other than Earth) and that no one who has that belief could also have a second belief (that all planets other than Earth are devoid of life). It concludes from these premises that some people do not have the second belief. The question asks you to identify the answer choice that employs reasoning most similar to that in this argument. Note that the conclusion of this argument follows logically from its premises: if no one could have both of two beliefs, and some people have one of them, then it must be that those people don't have the other one.

The Correct Answer:

C  Like the reasoning in the passage, (C) indicates that some people have a certain belief (that their dogs are emotionally attached to them) and that no one who has that belief could also have a second belief (that dogs are incapable of thought). (C) also concludes from these premises that some people do not have the second belief. This follows the same basic reasoning pattern as the argument in the passage, and as with that argument, the conclusion of the argument in (C) follows logically from its premises.

The Incorrect Answer Choices:

A  (A)'s conclusion indicates that a certain belief is true: computer chess programs really do sometimes beat human chess masters. The reasoning in the passage, in contrast, does not address whether the beliefs it considers are true. Moreover, (A)'s conclusion does not follow logically from its premises (which concern whether people have certain beliefs, not whether those beliefs are true). Compare this with the Overview's discussion of the reasoning in the passage.

B  (B)'s first premise, like that in the passage, indicates that some people have a certain belief: cats are not capable of guilt. Unlike the reasoning in the passage though, (B)'s second premise doesn't say anything about those people; instead, it is about a requirement for thinking that an animal is capable of guilt. Moreover, because this premise doesn't tell us anything about people who have the first belief, (B)'s conclusion doesn't follow logically from its premises. This is another way in which the reasoning in (B) is not similar to the reasoning in the passage.

D  (D)'s premises say that some people have a certain belief and that anyone who has that belief "probably" also has a second belief. The reasoning in the passage, in contrast, does not concern probabilities. Moreover, (D) concludes that some people  do not  have the second belief. That conclusion doesn’t follow logically from (D)'s premises, which instead suggest that some people probably  do  have the second belief. This is another way in which the reasoning in (D) is not similar to the reasoning in the passage.

E  (E)'s conclusion indicates that a certain belief is true: other planets really do have atmospheres that can support life. The reasoning in the passage, in contrast, does not address whether the beliefs it considers are true. Moreover, (E)'s conclusion does not follow logically from its premises (which concern whether people have certain beliefs, not whether those beliefs are true). Compare this with the Overview's discussion of the reasoning in the passage.

Some people believe there is intelligent life somewhere in the univers

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Some people believe there is intelligent life somewhere in the univers

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