LSAT 91, Logical Reasoning I, Q16, LSATHacks

LR Question 16 Explanation, by LSATHacks

QUESTION TEXT: If a belief is based on information from a reliable source…

QUESTION TYPE: Must be True

FACTS:

1. If a belief comes from a reliable source, it is reasonable to maintain that belief.
2. Some beliefs come from a reliable source, but are not self-evident nor grounded in observable evidence.

ANALYSIS: As with all Must be True questions, it will help to map it out.

All reliable source ➞ reasonable to maintain

Some reliable source ➞ not self-evident or grounded in observable evidence

From this, we can see that:

Some not self-evident or grounded in observable evidence ➞ reliable source ➞ reasonable to maintain

The argument told us that all beliefs from a reliable source are reasonable to maintain. This includes the ones which are from a reliable source but are not self-evident or grounded in observable evidence. We know, therefore, that there are some beliefs that are reasonable to maintain despite not being self-evident or grounded in observable evidence.

___________

1. We know this is not true – we can infer that there are some beliefs that are reasonable despite not having observable evidence.
2. We know this is false – we are told there are some beliefs from a reliable source that are not self-evident.
3. All we know is that a reliable source means a belief is reasonable. We don’t know if all reasonable beliefs come from reliable sources, or really anything about beliefs that do not.
4. We don’t know this. It’s possible that a belief can be self-evident without being grounded in observable evidence – we are only told about some that are neither.
5. CORRECT. We know there are beliefs that are not self-evident or grounded in observable evidence. Fact #2 above explicitly tells us this.

Recap: The question begins with “If a belief is based on information from a reliable source”. It is a Must be True question. Learn more about LSAT MBT questions in our guide to LSAT Logical Reasoning question types.

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