Q22 - All the evidence so far

[bnuvincent]

I found this one convoluted , could you please explain ?

[ManhattanPrepLSAT1]

Tough one. It's dense, long, and requires significant abstract thinking.

It must be true that one of four things will happen

1. Dr. G = Correct; Prof. H = Correct
2. Dr. G = Correct; Prof. H = Incorrect
3. Dr. G = Incorrect; Prof. H = Correct
4. Dr. G = Incorrect; Prof. H = Incorrect

The argument establishes that possibility 1 cannot be true, and from this concludes that either possibility 2 or possibility 3 must occur. The argument fails to consider the alternative possibility, that both Dr. G and Prof. H would be proven incorrect.

This is what we call a False Choice flaw. Any time someone concludes A by ruling out B without considering C, that's a False Choice. Recognizing this common pattern will save you the work of all that abstraction!

(A) says "at least one must have an erroneous method." The argument in the stimulus says exactly one one must be wrong. "At least one" and "exactly one" are not the same.
(B) has a conclusion that matches the evidence of the stimulus. So, not the answer.
(C) has a conclusion that does not match. So is not the answer.
(D) is a valid argument. He is either right or wrong. So examination would either prove him right or wrong.
(E) matches the False Choice reasoning of the stimulus that failed to rule out an alternative possibility. This argument does so as well by failing to consider that Maria might disconfirm both.

#officialexplanation

[jaydizzle]

Ok, I see your reasoning. I just don't get how B does not work as well.

(B) has a conclusion that matches the evidence of the stimulus. So, not the answer

Doesn't this mean it still has the same erroneous reasoning?

[ManhattanPrepLSAT1]

The simplest way to think about this is that the stimulus is says that "this experiment will confirm one of these theories at the expense of the other." This is a positive affirmation. One of these will be confirmed.

Answer choice (B) states "so this description must be inconsistent with David's view." That's the denial of a position.

Answer choice (E) states "so when Maria gives her opinion it will verify either David's or Jane's opinion." That's the positive affirmation of a position.

Remember, the most important part of the argument is the conclusion for Match the Reasoning and Match the Flaw questions!

[jamiejames]

The simplest way to think about this is that the stimulus is says that "this experiment will confirm one of these theories at the expense of the other." This is a positive affirmation. One of these will be confirmed.

Answer choice (B) states "so this description must be inconsistent with David's view." That's the denial of a position.

Answer choice (E) states "so when Maria gives her opinion it will verify either David's or Jane's opinion." That's the positive affirmation of a position.

Remember, the most important part of the argument is the conclusion for Match the Reasoning and Match the Flaw questions!

could you explain the "positive affirmation" part? What does the mean in terms of the answer? i know that positive affirmation is used in psychology for interaction between people, so I'm a little lost on the use here

[aungar.chatterjee]

2 things for answer B:

1. Per previous poster: "positive affirmation"---

In the stem, the conclusion says 1 of the 2 theories must be "confirmed" -- confirming something means positively proving it (the opposite would be disproving it or showing it's wrong).

Answer B says one of the 2 views must be "incosistent" (which is like saying it's wrong).

Answer E says Marie will "verify" 1 of the 2 theories-- that matches the stem -- "verify" and "confirm" are both positvely proving something.

2. Here's what I think B is saying:

Jane and David both saw a tree-- Jane thought the tree was an elm, and the way she described the tree was CONSISTENT with this opinion. Not entirely sure what consistent means here.

David saw the same tree and thought it was a beech--- so does that mean that the way Jane described the tree is not CONSISTENT with david's opinion (because remember, David's opinion is different from Jane)

Without 100% clarity on how "consistent" is used here, I think we can say that this does not have to be true. Imagine David agreed with jane's description-- he says "yes the tree has these exact features that Jane is describing-- BUT, i think these features show this is a beech tree, not an elm tree" ... so it's possible that Jane and David would describe the tree the same way, and each thinks that their description leads to a different conclusion-- either way this doesnt really match whats going in the stem.