LSAT Explanation PT 42, S2, Q23: Physics professor: Some scientists claim that

LSAT Question Stem

The physics professor's conclusion follows logically if which one of the following is assumed? 

Logical Reasoning Question Type

This is a Sufficient Assumption question. 

Correct Answer

The correct answer to this question is E. 

LSAT Question Complete Explanation

The question type for this problem is Sufficient Assumption, which means we need to find an answer choice that, if assumed, would make the physics professor's conclusion follow logically.

Let's break down the argument in the passage:

1. Premise: Some scientists claim that superheated plasma with failed electrical resistance is a factor in causing ball lightning.

2. Premise: If this were true, ball lightning would emit intense light and rise in the air (due to plasma's gas-like properties).

3. Premise: The physics professor observed instances of ball lightning that were of low intensity and floated horizontally.

4. Conclusion: Superheated plasma with failed electrical resistance is never a factor in causing ball lightning.

An "Evaluate" question for this argument could be: "Do all instances of ball lightning have the same cause?"

Now, let's analyze the answer choices:

a) This answer choice states that superheated plasma does not cause types of lightning other than ball lightning. However, this doesn't help us prove the conclusion that superheated plasma is never a factor in causing ball lightning. It is irrelevant to the argument and, therefore, incorrect.

b) The number of observers doesn't impact the validity of the physics professor's conclusion. Even if others observed the same phenomena, it doesn't necessarily prove that superheated plasma is never a factor in causing ball lightning. This answer choice is incorrect.

c) This answer choice suggests that ball lightning can have multiple causes. However, this information doesn't help us prove or disprove the conclusion that superheated plasma is never a factor in causing ball lightning. It is unclear how this assumption would affect the argument, so it is incorrect.

d) This answer choice repeats a premise already relied upon in the argument: that superheating gas-like substances causes bright light to be emitted. It doesn't provide any new information or assumptions to help justify the conclusion, so it is incorrect.

e) This answer choice states that all types of ball lightning have the same cause. If we assume this to be true, then the instances of ball lightning observed by the professor, which didn't exhibit the characteristics of superheated plasma, would be representative of all ball lightning. This assumption would justify the conclusion that superheated plasma is never a factor in causing ball lightning, making this the correct answer choice.