(so confused -- please help!) PTC.S2.Q22

thscr176

Hello!

Could someone please help me figure this AP question out? There's no explanation video for it. The median score of someone who got it right is a 173, and I am aiming for a 170+.

Stimulus: "One can be at home and be in the backyard, that is, not in one's house at all...."

Question Stem: "Which one of the following most accurately describes the relationship between the argument's conclusion and its claim that one can be at home without being in one's house?"

Answer Choices:
A. (not correct)
B. (not correct)
C. (CORRECT)
D. (not correct, this is the one I chose)
E. (not correct)

Admin Note: Edited. It is against our Forum Rules to write out the entire LSAT question and answer choices on the Forum.

Clemens_

Formalize as follows:

"One can be at home and [...] not in one's house at all."

(P1) HOME <-s-> not HOUSE

"One can also be in one's house but not at home [...]."

(P2) HOUSE <-s-> not HOME

"So one's being at home is not required for one's being in one's own house."

(C) Not (HOUSE -> HOME)

In other words: The argument establishes the conclusion that being at home is not a necessary condition for being in one's house.

The question now is: What is the relation between the conclusion (C) and premise (P1)? Note here that (P1) could falsify other conditional statements, notably the statement HOME -> HOUSE. If it were true that you can be at home while not at your house, it cannot be the case that being in one's house is necessary for being at home. However, this is not the conditional statement that we are considering in the conclusion; (P1) does not show up again in the subsequent argumentation.

Note further, however, that (P2) and (C) are logically equivalent. Both propositions state: "You can be at your house but not at home," also expressible as "There are some people who are at their house but not at home" as well as as "It is not the case that you need to be at home to be at your house." All of these expressions mean the same thing; the conclusion (C) just reformulates (P2).

Long story short, (P2) and the conclusion (C) are logically equivalent; whereas (P1) remains argumentatively inert. This is why answer choice (C) is correct.

As a side note, these sorts of logic heavy considerations occur primarily in the early PTs and are much rarer in later contexts. If you find this inaccessible, maybe consider working primarily with later PTs, they tend to be less formal and more representative of what you will likely encounter on a present-day LSAT. The formal logic you'll actually need likely comprise mostly primarily the valid argument forms discussed in the core curriculum and their invalid counterparts.

thscr176

Thank you so much!