Sufficient AssumptionDiff: Hardest
Logic Breakdown
Passage Summary: To find aliens soon, they have to be smart. We can't go to them, and only smart ones can talk to us.
Conclusion: We will only be able to detect sentient life outside our solar system in the near future if those beings are at least as intelligent as humans.
Reasoning: We currently lack the technology to send spacecraft to other solar systems, and any alien life capable of communicating with us would necessarily possess human-level intelligence.
Analysis: This is a Sufficient Assumption question that hinges on a missing link between the methods of detection and the conclusion's requirement for intelligence. The author identifies two specific ways to find sentient beings—visiting them or communicating with them—and notes that neither works for unintelligent beings in the near future. To make the argument logically airtight, we need an assumption that guarantees these are the only two ways we could possibly determine their existence. Look for an answer that eliminates any other methods of detection, such as long-range visual observation.
Conclusion: We will only be able to detect sentient life outside our solar system in the near future if those beings are at least as intelligent as humans.
Reasoning: We currently lack the technology to send spacecraft to other solar systems, and any alien life capable of communicating with us would necessarily possess human-level intelligence.
Analysis: This is a Sufficient Assumption question that hinges on a missing link between the methods of detection and the conclusion's requirement for intelligence. The author identifies two specific ways to find sentient beings—visiting them or communicating with them—and notes that neither works for unintelligent beings in the near future. To make the argument logically airtight, we need an assumption that guarantees these are the only two ways we could possibly determine their existence. Look for an answer that eliminates any other methods of detection, such as long-range visual observation.
Passage Stimulus
Passage Redacted
Unlock Full Passage18.The argument's conclusion can be properly inferred if which one of the following is assumed?
Correct Answer
D
If a sentient being on another planet cannot communicate with us, then the only way to detect its existence is by sending a spacecraft to its planet. Combined with the premise that we cannot send spacecraft in the near future, this forces the only remaining route—communication—which (per the premises) requires at least human-level intelligence. That yields D -> H, exactly the conclusion.
Upgrade Your Prep
Ready to go beyond free explanations?
LSAT Perfection is the #1 modern LSAT prep platform, trusted by thousands of students for comprehensive test strategies, advanced drilling, and full analytics on every PrepTest.
Detailed explanations for 59 PrepTests
Advanced drillset builder
Personalized analytics
Built-in Wrong Answer Journal