LSAT 105 | Section 4 | Logical Reasoning: Q13

LR Question 13 Explanation

QUESTION TEXT: Television allows us to transmit images …

QUESTION TYPE: Flawed Reasoning

CONCLUSION: There’s no alien intelligence in any of our neighboring star systems.

REASONING: Our TV signals have already reached neighboring star systems. We haven’t received any alien messages and, as far as we know, our signals haven’t been recognized.

ANALYSIS: So we have no evidence of alien (extraterrestrial) intelligence. That’s what the reasoning tells us. They haven’t recognized our signals and we haven’t gotten any from them.

But then the conclusion says they don’t exist. That’s a pretty big jump.

Lots of other possibilities could be true:

• They exist but haven’t detected our signals
• They detected them but can’t respond
• They responded and we haven’t recognized it
• They simply chose not to respond

The argument confuses lack of evidence for something as being evidence against that thing. You can’t do that.

___________

1. The stimulus doesn’t depend on how we define “messages”. We can understand what they mean without this.
2. CORRECT. The argument goes from no recognized evidence to they don’t exist.
3. The conclusion is only about neighboring star systems. Intelligence elsewhere is irrelevant.
4. Whether spacecraft carried messages has nothing to do with the inference from no response to no extraterrestrial intelligence.
5. If most star systems are uninhabited, that would actually make the conclusion seem more plausible, not less.