LSAT 105 | Section 4 | Logical Reasoning: Q20

LR Question 20 Explanation

QUESTION TEXT: James: Chemists have recently invented …

QUESTION TYPE: Method of Reasoning

JAMES’ ARGUMENT: Nuclear waste can be used to extract rhodium, which is used in catalytic converters, which reduce pollution. So nuclear power is contributing to a cleaner environment.

ARGUMENTS: MARTA’S ARGUMENT: That conclusion doesn’t follow right now because the rhodium extraction technique is still experimental and hasn’t actually changed where manufacturers get their rhodium.

ANALYSIS: James moves from: Nuclear waste could be a source of rhodium

to

Nuclear power is already contributing to a cleaner environment.

That would imply this technique is actually being used and affecting rhodium production.

Marta attacks exactly that assumption. She says: none of this has happened yet.

The technology is still experimental, so there hasn’t actually been a shift in rhodium sources. Therefore, James is prematurely concluding that nuclear power is already contributing to cleaner air.

Suppose I say: “Scientists invented a way to turn ocean water into jet fuel. Therefore, the oceans are helping power airplanes.”

You’d object: “Wait … nobody’s actually using that method yet.”

That’s exactly what Marta’s doing.

___________

1. Marta never disputes the truth of James’s premises. She agrees that the technique is effective. She also doesn’t dispute that catalytic converters reduce pollution.
2. Marta says nothing about advocates of nuclear power or their credibility. She attacks the argument itself, not the people who support nuclear power.
3. James isn’t assuming his conclusion. He isn’t saying: Nuclear power contributes to a cleaner environment because nuclear power contributes to a cleaner environment.
4. CORRECT. She pointed out an important fact James failed to consider: that the technique is still experimental. This undermines James’ conclusion that nuclear power is currently contributing to a cleaner environment.
5. Marta doesn’t claim the premises are as implausible as the conclusion. In fact, she accepts the key premise that the technique is effective. Her objection is that the premises don’t yet justify the conclusion because the technology isn’t being used in practice.