Subscription pricing
http://classic.7sage.com/lsat_explanations/lsat-61-section-2-question-23/
So in JY's explanation the stimulus represents invalid argument form 4. But I'm having trouble seeing this. Had the second sentence read "most BRICK houses on river street with front yards also have two stories" it would have been a lot clearer to me. But it just says "most of the houses on river street that have front yards also have two stories" So presumably there could be 100 wooden houses on river street with front yards and only 5 brick houses. The 5 brick houses could have front yards but not two stories while the 100 wooden houses all have two stories. So I'm not sure how we are justified in claiming most brick houses with front yards have two stories. Very confused on this.
0
11 comments
[Deleted]
But it's an important point to clarify—I know I definitely mulled over whether this was a vital distinction on a couple of my attempts at this Q (it was my nemesis for a while).
I agree. I think it's not a point that comes up since all the answer choices follow that same set up.
@cai19930321867 that's a good point; I think the argument form stands whether you notate the elements as subsets or unique variables—word?
Both also have that part to whole problem as well, I would say.
BRH is not the same as houses in general, they are a subset. This is also true in D where all legislators aren't the same as public servants in general, they are one body of people who are public servants (where are the judges, social workers, etc).
Premise: P --most--> not R
Therefore: L --most--> not R
Yes, here I see you're saying "not R" — is this the rub?
Stimulus:
BH —> FY
FY -most-> TS
BH -most-> TS
Form in generic terms:
A —> B
B -most-> C
A -most-> C
AC D [rearranged to match stimulus]:
L —> PS
PS -most-> NRO
L -most-> NRO
I think it's most helpful with the "never run for office" condition in the answer choices to think of them as a characteristic as opposed to a negation of "run for office" (meaning, NRO = C in the generic form).
"No BRH having front yards" makes me wonder if you are thinking of this as a negation?
Let me try to be more clear.
Stimulus:
BHR (Brick houses on river street)
F (front yard)
HRF (Houses on river street that have front yards)
2 (have two stories)
Premise: BRH --> F
Premise: HRF ---most--> 2
therefore: BRH -most-> 2
JY says this is invalid argument form number 4 but I don't see how we are justified in connecting F --> HRF
My objection is that BRH and HRF are not the same. No BRH having front yards is consistent with most HRF having front yards.
Correct Answer choice:
L (legislators)
not R (have not run for office)
P (public servant)
Premise: L ---> P
Premise: P --most--> not R
Therefore: L --most--> not R
To me this is very clearly argument form number 4 (A-->B--most--> C therefore A ---most--> C)
If the argument had said "most BRICK houses on river street with front yards also have two stories," the argument will be valid. The argument starts with information about brick houses: they have front yards. Then, the argument discusses houses with front yards: most have two stories. You draw the "most arrow" from "front yard" to "two stories" because the corresponding premise is about front yard. In other words, an arrow from FY is independent of the arrows to FY.
Right, I undestand that its invalid reasoning. But JY equates Most houses on river street have front yards with being the same as most BRICK houses on river street having forn yards. Does that make more sense?
I'm not 100% clear on your question—
Would we still be justified in claiming most brick house front yards have two stories??
My short answer is no ... That's the faulty conclusion this PF/MtF question comes to. Would you clarify what you're asking?