LSAT 155 - Section 1 - Question 15

Summary

Most cats like to go outside when the temperature is above freezing.
If Jamil lets his cat go outside, then at least one of his family members is outside.
If any of Jamil’s family members are outside, then it’s sunny or hot outside.

Very Strongly Supported Conclusions

If it’s not sunny and it’s not hot, Jamil’s family members are not outside.
If it’s not sunny and it’s not hot, Jamil’s cat is not outside.
If Jamil lets his cat out, then it’s sunny or hot.

A

If Jamil’s cat is outside, then the temperature is above freezing.

Unsupported. If Jamil’s cat is outside, then one of his family members is outside. And if one of his family members is outside, then it’s sunny or hot. Jamil’s family member and his cat could be outside when it’s below freezing but still sunny.

B

If Jamil’s cat is not outside, it is cloudy and it is not hot outside.

Unsupported. If Jamil’s cat is outside, then it’s sunny or hot outside. But the fact that his cat is not outside tells us nothing about whether it’s sunny or hot. It’s possible that it is sunny or hot outside, but Jamil just didn’t want to let his cat out.

C

If the sun is shining or it is hot outside, Jamil’s cat is probably outside.

Unsupported. “Sunny or hot” is not a sufficient condition for anything. We know that Jamil’s family members (and thus his cat) will only be outside when it’s sunny or hot. But the fact that it’s sunny or hot tells us nothing about whether his family members or his cat are out.

D

If at least one member of Jamil’s family is outside, then Jamil’s cat is outside also.

Unsupported. If at least one family member is outside, then it’s sunny or hot outside. This doesn’t necessarily mean that the cat is also outside. We just know that if the cat is out, then at least one family member is also out. (D) gets this backward.

E

If the sun is not shining and it is not hot outside, Jamil’s cat is not outside.

Very strongly supported. By taking the contrapositive of the conditional chain below, we see that if it’s not sunny or hot, then Jamil’s family members aren’t outside. And if they’re not outside, then Jamil won’t let his cat out. So if it’s not sunny or hot, his cat can’t be out.

This is an Inference question. The question stem says “properly inferred.”

This question contains two sets of information, one of which is irrelevant and the other of which is what generates the inference. This question is actually closer to an MSS question than an MBT question. This is rare. Most questions that contain “inferences” in the stem are logically tight. This question is conspicuously an exception.

The stimulus states that “most cats like to go outside to play when the temperature is above freezing.” Translating this statement into logic, notice the conditional indicator "when" and the quantifier "most." For conceptual simplicity, let's kick the sufficient condition up into the domain. We are now talking strictly within the domain of when the temperature is above freezing. Under that domain, we are saying that of the set of cats, most of them like to go outside to play. Again, all of this is under the domain of when the temperature is above freezing. Now, as it turns out, and there's no way you could know this beforehand, this statement is completely irrelevant. The only way you’ll realize this is when you consider the answers. None of them make use of this statement.

The next statement creates a conditional chain from which we infer the correct answer. We are now talking about a specific cat. Jamil does not allow his cat to go outside unless at least one member of his family is outside. Translating this unless statement, we get the conditional that if Jamil's cat is allowed to go outside, then at least one member of his family is outside. Next we learned that Jamil's family members go outside only when the sun is shining or it is hot outside. This conditional connects directly to the previous one. If at least one member of his family is outside, then it must be either that the sun is shining or it is hot or both:

J’s cat allowed outside → J’s fam member outside → sun or hot

Now we can run a contrapositive. If the sun is not shining and it is not hot outside, then no member of Jamil's family is outside, then Jamil's cat is not allowed to go outside.

Does that mean Jamil's cat is not outside? This is the space between a reasonable or “proper inference” versus a deductively valid, must be true inference. In order to draw the conclusion that Jamil's cat is not outside, we have to assume that if Jamil's cat is not allowed to go outside, then it is not outside. This assumption is what Correct Answer Choice (E) requires. The fact that this is the correct answer reveals that the test writers think “properly inferred” is a lower standard of proof than “must be true.” Or the test writers made a mistake, though that’s highly unlikely.

I said at the beginning that this question was unusual because the overwhelming majority of questions using the “properly inferred” standard deliver answer choices that meet the higher “must be true” standard. But just because the test writers tend to overshoot a lower bar doesn't mean that the bar has been raised. They are just overshooting what has always been and presently is a lower bar. This is the same lesson we draw from some easier Weaken questions where the correct answer is identical to the ideal answer. That’s just the test writers overshooting the bar. On harder Weaken questions, we see the correct answer requiring assumptions.

The more salient decision for you is strategy: what to do under timed conditions? How do you respond when you detect this gap? The same as you always do. You pick the best answer. Looking at the other answers will reveal that (E) is the best out of the bunch for having made the fewest assumptions.

Answer Choice (A) says if Jamil's cat is outside, then the temperature is above freezing. This answer makes exactly the same assumption that (E) makes, namely that if Jamil's cat is outside, then he was allowed outside. But in addition it makes a mistake in logic. If Jamil's cat is allowed to go outside, then either the sun is shining or it is hot outside or both. It's possible that the temperature is not above freezing because the sun could be shining.

Answer Choice (B) says if Jamil's cat is not outside, then something something. At this point you can stop reading because (B) makes a logical mistake, the oldest mistake in the book: sufficiency-necessity confusion. Jamil's cat not being outside can only be a necessary condition according to the chain we have above.

Answer Choice (C) makes the same logical mistake as (B): sufficiency-necessity confusion. The sun is shining or it is hot outside is at the tail end, the necessary condition end of the chain. You cannot start a sufficient condition with the sun is shining or it is hot outside. It leads nowhere.

Answer Choice (D) says if at least one member of Jamil's family is outside, then Jamil's cat is outside also. This answer also requires the same assumption that (E) requires. Notice it also says the cat is outside as opposed to Jamil's cat is allowed outside. Additionally, (D) makes a sufficiency-necessity confusion. If Jamil's cat is allowed to go outside, then at least one member of his family is outside, not the other way around.