LSAT Explanation PT 34, S3, Q6: Standard archaeological techniques make it possible

LSAT Question Stem

Which one of the following, if true, most seriously weakens the argument? 

Logical Reasoning Question Type

This is a Weaken question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

Let's first analyze the argument in the passage. The argument has the following structure:

Premise 1: Standard archaeological techniques can determine the age of anything containing vegetable matter, but only if the object is free of minerals containing carbon.

Premise 2: Prehistoric artists painted on limestone with pigments composed of vegetable matter.

Premise 3: It is impossible to collect samples of this prehistoric paint without removing limestone, a mineral containing carbon, with the paint.

Conclusion: It is not possible to determine the age of prehistoric paintings on limestone using standard archaeological techniques.

The question type is Weaken, meaning we need to find an answer choice that, if true, would undermine the conclusion or the relationship between the premises and the conclusion.

Now let's discuss each answer choice:

a) This answer choice mentions different techniques for collecting samples, but it doesn't address the issue of carbon in the samples. It doesn't directly weaken the conclusion, so it's not the correct answer.

b) This is the correct answer. If laboratory procedures can remove all the limestone (and thus, the carbon) from a sample of prehistoric paint on limestone, then it becomes possible to determine the age of the paintings using standard archaeological techniques. This directly weakens the conclusion.

c) Although this answer choice provides information about the age of limestone, it doesn't address the issue of determining the age of the prehistoric paintings, which is the main focus of the argument. Therefore, it doesn't weaken the conclusion.

d) This answer choice is irrelevant to the argument, as it doesn't address the issue of carbon in the samples. It doesn't weaken the conclusion.

e) The proportion of carbon in limestone is not relevant to the argument. The issue is the presence of carbon in the samples, not the proportion. This answer choice doesn't weaken the conclusion.

In summary, the correct answer is B because it directly addresses the issue of carbon in the samples and provides a way to remove it, making it possible to determine the age of prehistoric paintings on limestone using standard archaeological techniques, thus weakening the conclusion.