Necessary AssumptionDiff: Easy
Logic Breakdown
Passage Summary: The author argues that since no aliens have called us yet, there must not be any advanced civilizations nearby. The logic is that if they were there, they would have definitely seen us and reached out.
Conclusion: Scientists can conclude that there are no technologically advanced civilizations within 50 light years of Earth.
Reasoning: If such a civilization existed, they would have detected us and would have been able to contact us easily.
Analysis: The argument relies on a massive missing link between the ability to contact us and the act of doing so. It assumes that if an advanced civilization could contact us, they actually would want to. To find the necessary assumption, look for a statement that bridges this gap—specifically, that an advanced civilization would not choose to remain silent or hidden. This is a classic 'absence of evidence is evidence of absence' flaw that requires a specific bridge to function.
Conclusion: Scientists can conclude that there are no technologically advanced civilizations within 50 light years of Earth.
Reasoning: If such a civilization existed, they would have detected us and would have been able to contact us easily.
Analysis: The argument relies on a massive missing link between the ability to contact us and the act of doing so. It assumes that if an advanced civilization could contact us, they actually would want to. To find the necessary assumption, look for a statement that bridges this gap—specifically, that an advanced civilization would not choose to remain silent or hidden. This is a classic 'absence of evidence is evidence of absence' flaw that requires a specific bridge to function.
Passage Stimulus
Passage Redacted
Unlock Full Passage4.Which one of the following is an assumption required by the argument?
Correct Answer
D
The argument needs the assumption that a technologically advanced civilization that detected us would want to and thus would contact us. Negation test: If such a civilization would not want to communicate, then even if it existed, there might be no contact, so scientists could not rule out its existence—destroying the argument.
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