LR Question 9 Explanation
QUESTION TEXT: Astronomer: Proponents of the hypothesis that life…
QUESTION TYPE: Flawed Reasoning
CONCLUSION: There is good reason to think that the hypothesis is false.
REASONING: There’s no evidence for the hypothesis.
ANALYSIS: I intentionally simplified the conclusion and reasoning to make the error clearer. You can’t conclude that something is wrong just because there’s no evidence to support it. To prove that something is wrong you need actual evidence against it.
The astronomer only has lack of evidence. He should have concluded “I don’t know if the hypothesis is right or wrong. I have no evidence for or against it.”
Instead, he assumes that the hypothesis is wrong. When you have no evidence, you can’t do that. You have to say “I don’t know”. Something can be right even if you currently lack evidence that it is.
Don’t let the science talk frighten you. Almost all of it is fluff. The entire argument is in the final sentence.
___________
- CORRECT. The astronomer says there is ‘good reason’ to think that the hypothesis is false. Good reason = evidence. Why does the astronomer think that there is evidence against the hypothesis? In the final sentence, his only proof is that there is no evidence for the hypothesis.
- The astronomer didn’t say that the hypothesis is inherently implausible. He just said that there’s currently no evidence for it.
- The astronomer didn’t mention any hypothesis that is equally likely to be true.
- Which premises contradict the conclusion? If the flaw didn’t happen, then an answer can’t be correct.
- This isn’t a flaw. If your opponent makes a true claim, then you must grant that it’s true, even if it weakens your argument.
More Resources for Flaw Questions
- Flaw drills: Use these to practice making examples of abstract flaws.
- Intro Course lesson: This intro course lesson covers Flaw questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers flaw questions.
Hi,
I didn’t interpret “good reason” to mean “evidence” (as you said in the explanation). answer choice A really threw me off by saying that the author had interpreted that there was evidence against the hypothesis.
To me, the author’s mistake was thinking that not having good evidence means you’re wrong. But answer A says that not having good evidence means there is evidence against. Not sure how that’s correct.
I think your phrasing and answer A are saying the same thing.
When you say the author thinks “not having good evidence means you’re wrong,” that means the author is treating the lack of evidence as a reason to believe the hypothesis is false.
That is what answer A calls “evidence against.” It does not mean the author found some separate, direct evidence disproving the hypothesis. It means the author is acting as though the absence of evidence for the hypothesis counts as a reason against the hypothesis.
So the two versions line up like this:
“No good evidence for this hypothesis”
→ “This hypothesis is probably wrong”
That jump is the flaw. Answer A just describes the second part as “evidence against” because the astronomer concludes that there is “good reason” to think the hypothesis is false.
Hope that helps! Let me know if you have further questions!