#19 - When a stone is trimmed by a mason and exposed to the

[Jamena Pirone]

Hi elewis,

The stimulus isn't necessarily saying that organic matter can only grow on trimmed surfaces, but rather that you can test the age of the organic material that is trapped under the varnish coating of trimmed surfaces in order to determine how old a monument is. Answer Choice B points out that this method isn't reliable in places where people reuse old stones to make new monuments. That is, you can't determine the age of the monument by looking at the age of the trapped varnish if there is a possibility that the monument used older stones. The organic material that is tested could have been trapped on the stone from the first time the stone was cut, thousands of years earlier.

Look at it this way: The author says that the monument being built thousands of years ago is what causes the effect of the organic matter therein being thousands of years old. But there is an alternate cause for finding organic material so old; namely, the stones used are old, but the monument itself isn't.

I hope that clears things up!

[LearntheLSAT]

Hello,

I found this question to be very verbose and contained a lot of useless information to answer the conclusion. I honestly didn't even understand what I was looking for. I selected A because I thought we were looking for an alternative as to why the rock varnish was in the organic material For future, is there an easier way to know exactly WHAT we are looking for in the causal relationship? Sorry if this is confusing, my thought-processing is a little off. I'm not sure how I would have concluded that we were looking to resolve issues regarding the stone and monument, and not the organic matter/varnish.

Thanks in advance!

[KelseyWoods]

Hi LearntheLSAT!

When you're analyzing an argument on the LSAT, it helps to focus on the conclusion the author is trying to make and the premises the author has used to support that conclusion. This helps you focus on the main components of the argument. In this case, a Weaken question, understanding that argument structure is the key to anticipating how to attack that argument.

In this argument, the conclusion is that the monument was built long before 1492. Why does the author believe the monument was built before 1492? Because it has 1,000-year old organic matter underneath the rock varnish. From the first sentence, we know that rock varnish develops after a stone has been trimmed by a mason. So basically, the author's argument is that 1,000-year old organic matter underneath the rock varnish on stone = really old monument.

To weaken an argument, we just need to show that the premises do not necessarily equal the conclusion. There are usually multiple ways to weaken any argument so we don't want to prephrase too specifically because we don't know which of the several ways to weaken an argument the testmakers are going to give us in the answer choices. But with a clear understanding of the argument structure, we know that we are looking for an answer choice which shows that really old organic matter on the stones does not necessarily equal really old monument. So basically, we need to come up with another explanation for the really old organic matter on the stones.

The author observed that there was really old organic matter on the stones and concluded that it must because the monument is really old. We need to take that really old organic matter on the stones and come up with a different explanation for it. Answer choice (B) does this for us by saying that the stones themselves could be really old, without the actual monument being really old. Thus, it provides another explanation for the really old organic matter on the stones besides a really old monument.

Always focus on the conclusion and how the author got to that conclusion. It will help you find the weak spots in the argument and help you home in on what exactly you should be looking for in an answer choice.

Hope this helps!

Best,
Kelsey

[LearntheLSAT]

Hi Kelsey,

I appreciate you imparting your very specific analysis of the question. It was hard for me to digest, but it is a lot more clear now and I really appreciate you helping me!!