Q7 - When Cortez arrived in Mexico

[rsmorale]

First Sentence: Background Information
Premise: pre-Columbian inhabitants of Mexico began to use rubber around AD 1000
Conclusion: The game must have originated sometime between AD 1000 and Cortez' arrival.

Goal: Necessary Assumption

A- the fact that they played on all ceremonial occasions is not assumed
B-making of rubber balls is irrelevant to conclusion
C-popularity of game is not assumed

D - Correct answer; although I do not see why.
E - I chose this because it seemed like negating it destroyed the argument.

Why is D the credited response, and E faulty? Doesnt E represent the conclusion better?

[demetri.blaisdell]

This is a good question that shows how answers that seem out of scope at first can still be the correct answer to Necessary Assumption questions. I think your diagram of the argument core is missing a premise.

In 1519, game was played with rubber ball + Mexicans started using rubber in 1000 --> Game was invented between 1000 and 1519

The first premise is important because it introduces the 1519 part of the conclusion and it also tells us why we're focused on rubber in connection with the game.

Necessary assumptions can seem out of scope at first. (D) is a classic case of this. Why does it matter whether rubber was the original substance for ball construction?

The argument is dating the invention of the game based on when rubber was invented (or first used). Synthetic materials in modern basketballs were probably invented in the last decade. When was basketball invented? What if the Mexicans played with the heads of their enemies for thousands of years and then switched to rubber when they discovered it in the year 1000 because it bounced better? So the only way this argument can work is if the game was played from the beginning with rubber. (D) removes this "heads of enemies" possibility.

(A) is actually out of scope. We care about when it was invented not why/when it was played.

(B) The conclusion is that the game was invented some time between 1000 and 1519. If it was the very last thing the Mexicans did before Cortez arrived (I'm applying the negation test here), the argument still works. This isn't necessary for the argument.

(C) is also out of scope. We don't care where in Mexico it was popular. We only care when it was invented.

(E) is inviting us to question the premise that rubber was first used in 1000 A.D. (E) tells us that Cortez was the one who determined when the Mexicans started using rubber. For the purposes of the LSAT, Daffy Duck could have been the archeologist who determined when the Mexicans invented rubber. If we're given that as a premise, we can take it to the bank. Remember, we are addressing the gap between the premise and the conclusion---not questioning the premise or the conclusion themselves.

I hope that makes this one clear for you. Let me know if you have any questions.

Demetri

[rsmorale]

Thanks, Demitri. Appreciate the "heads of their enemies" analogy. I definitely mistook the first premise for background information. Had I considered this premise more strongly, I would have seen the focus on dating.

Thanks for helping me!

[DylanM253]

I wouldn't say that B is necessarily irrelevant to the conclusion because we are still trying to get a gauge on when the game started, but rather that we're focusing specifically in relation to the game being created. That coupled with the negation makes the answer incorrect.