LSAT 134 | Section 2 | Logical Reasoning: Q16

LR Question 16 Explanation

QUESTION TEXT: Anyone who believes in extraterrestrials believes in UFOs …

QUESTION TYPE: Flawed Parallel Reasoning

CONCLUSION: Aliens don’t exist.

REASONING: Anyone who believes in aliens believes in UFOs, and UFOs don’t exist.

ANALYSIS: Notice the switch between beliefs and facts? That’s where the argument goes wrong.

It says:

• If someone BELIEVES in aliens, they also BELIEVE in UFOs.
• UFOs don’t exist.
• So, aliens don’t exist.

The issue is that the relationship between the beliefs doesn’t tell us whether the actual things are true or false.

If we were talking about only facts throughout the argument, then it’d be a good argument. For example:

• If A is true, then B must be true.
• B is false.
• So, A must be false.

That works because facts are directly dependent on each other.

But here we are talking about what people believe. Just because someone who believes in aliens also believes in UFOs doesn’t mean that disproving UFOs automatically disproves aliens.

So we need an answer choice that also confuses a relationship between two beliefs with a relationship between two facts, and incorrectly uses the falsity of one to prove the falsity of the other.

___________

1. CORRECT. This also confuses beliefs and facts. Believing in unicorns and centaurs depends on each other, but that doesn’t mean knowing whether centaurs are fake helps us determine the truth about unicorns.
2. Valid argument. If believing in unicorns requires believing in centaurs, then someone who rejects centaurs cannot believe in unicorns.
3. This reverses the relationship. Not believing in unicorns doesn’t tell us anything about whether someone believes in centaurs. And this doesn’t connect anything back to whether unicorns and centaurs exist (facts).
4. The stimulus makes no claims about what’s justified.
5. This concludes that a belief in centaurs is mistaken. That’s a fine argument. The mistake in the stimulus is that the conclusion is about facts based on a premise about beliefs.