Logical Reasoning

PT142 · S1 · Q12 Archaeologists are discovering

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Archaeologists are discovering a great deal about the Sals culture.

Conclusion (Thus)

The Sals did not smelt iron.

Evidence

The Sals did not have a word for iron (even though they had some for copper and bronze, which we know they did smelt).

Evaluate

The #1 reason the author offers for why we should think the Sals did not smelt iron is that they didn't have a word for iron.

If we picture the conclusion as a logic path we're trying to build, it would look like this:

Sals --------------------------------------> didn't smelt iron

What part of that path does the evidence provide? Sals --------> didn't have distinct word for iron

So what part of the path is missing? didn't have ---------------> didn't distinct word for iron smelt iron

Goal

The correct answer will need to take us from that launching pad "didn't have a distinct word for iron" and get us to the landing zone of "didn't smelt iron".

Any answer choice that isn't providing a rule in the form of, if xyz, then didn't smelt iron or its contrapositive if smelted iron, then not xyz is functionally useless to us.

12.

The conclusion drawn above follows logically if which one of the following is assumed?

  1. If a culture had a

    Unrelated to Goal

    This is a rule that looks like this: xyz ----> did smelt that metal But to prove the conclusion we're trying to prove, we need a rule that looks like this: xyz ---> did not smelt that metal Were we to contrapose this answer choice, it would put "did not smelt" on the left of the arrow, where it's useless to us.

    19% picked this

  2. If a culture was unfamiliar

    Unrelated to Goal

    To prove the conclusion we're trying to prove, we need a rule that looks like this: xyz ---> did not smelt that metal This answer doesn't have "did / didn't smelt" language in it at all, so it's useless to us.

    3% picked this

  3. If a culture smelted copper

    Unrelated to Goal

    To prove the conclusion we're trying to prove, we need a rule that looks like this: xyz ---> did not smelt iron This answer does have "did / didn't smelt" language, but it's specifically about copper and bronze. You could use this answer to prove that a culture didn't smelt copper, bronze, or both. But we need a rule we can use to prove that iron wasn't smelted.

    2% picked this

  4. If a culture did not

    If-Conclusion

    To prove the conclusion we're trying to prove, we need a rule that looks like this: xyz ---> did not smelt that metal The conclusion is always on the right side of the arrow. This answer puts the conclusion into the "if" condition. Any time you see the conclusion on the left of the arrow, that answer is wrong. If you didn't know that fun fact, then here is how you might think about it -- you'd start by contraposing this answer choice, so that the right side of the conditional better lines up with some language from the conclusion. If a culture was → then that culture familiar with a metal smelted that metal Could we apply this rule to the Sals, and then derive the conclusion that the Sals did not smelt iron? Well, iron is a metal. Were the Sals familiar with iron? Hmm. [re-read] It doesn't say. So we have no information that triggers this rule. Not to mention, if we thought that the Sals were familiar with iron, this rule would tell us that the Sals did smelt iron, which would contradict the conclusion we're trying to prove.

    2% picked this

  5. Correct

    If a culture smelted a

    Why this is right

    To prove the conclusion we're trying to prove, we need a rule that looks like this: xyz ---> did not smelt that metal Our answer choice is providing this: did smelt a metal --> had a distinct word for it This answer is set up in contrapositive form, meaning the negation of the conclusion is on the left side of the arrow. Why? Because -- this is the correct answer. The test writers have to disguise its appeal, so they manipulate it into contrapositive form. We assess answers, on Sufficient Assumption and Principle, primarily for whether the answer choice has the Conclusion on the right side of the arrow, or whether it has the negation of the Conclusion on the left side. (E) as written: if you smelted it → then had distinct word for it (E) contraposed: if you didn't have a distinct → then you didn't word for a metal smelt that metal We were told, in the evidence, that the Sals didn't have a distinct word for iron, which is a metal. Thus, according to this rule, the Sals didn't smelt iron. We proved the conclusion! (and thank you, to LSAC, for this enjoyable homage to the classic childhood principle, 'if you smelt it, you dealt it')

    Skill tested: Sufficient Assumption · how this choice captures the argument's function is the move to repeat next time.

    74% picked this

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