Q21 - the mayor was not telling

[chike_eze]

Correct (A)
Type: ID flaw

Argument: Bridge renovation is wasting taxpayers' money because its parent project is wasting money.

Flawed assumption: If something is true for X, then it is also true for each sub-component of X. This is not necessarily true.

Equivalent example: just because a car is totalled, doesn't mean you can't salvage the parts.

A. States the flaw exactly!

B. This is a hasty generalization error not exhibited in the arg
C. Author did not attack mayor's character
D. The author did not make a circular argument
E. This was not the main thrust of the arg.. and was used appropriately by the author to boost his premise

[giladedelman]

Looks good! Watch out for this kind of error and its counterpart, assuming what's true of the part must be true of the whole.

[isaac.botier]

Q21. (A)
Question Type: Flaw (Assumption Family)

Another assumption question family so we have another core to find. The core is:

The Southern Tier Project was egregiously wasteful (according to commission report) + the bridge renovation was a part of the Southern Tier Project --> The Mayor was not telling the truth when he said that the bridge renovation didn’t waste taxpayers money.

There are a number of gaps in the core that we could identify before considering the answer choices. One is that the argument is assuming that the commission's report was accurate. Maybe the mayor had just upset everyone on the commission by outlawing huge sugary drinks. The commission members, low on sugar and frustrated, then decided to get back at him by making the Southern Tier Project seem like a colossal waste of money.

We should also consider that the bridge renovation could have been one of 100 projects in the Southern Tier Project. It’s possible that the bridge renovation ended up being profitable and the 99 other projects were huge wastes of money. This would make the Southern Tier Project a huge waste of money as a whole even though the bridge renovation was profitable.

This kind of logical flaw recurs on the LSAT. We can’t assume that is what is true about a whole is true about each of its parts.

(B) is kind of the reverse of what we need. In the prompt we are assuming what’s true about the whole is true about the part. This answer choice is telling us what’s true about a part is true about the whole. (B) would possibly work if the argument was:

the bridge renovation was a huge waste of money + the bridge renovation was part of the Southern Tier Project --> The mayor was not telling the truth when he said The Southern Tier Project didn’t waste taxpayers money.

(C) is incorrect because the argument is using evidence, it’s just using it poorly. This is true of all questions in the Assumption Family. The two premises we listed above are the evidence. The flaw is in how the evidence presented is meant to lead to the conclusion.

(D) is incorrect because we don’t have circular logic as the flaw in our prompt. Here is a hypothetical core that displays circular logic:

We know that anyone who takes Manhattan LSAT is prepared for the LSAT, since anyone who is not prepared for the LSAT didn’t take Manhattan LSAT.

Premise: -P --> -MLSAT

Conclusion: MLSAT --> P

Key: MLSAT = takes Manhattan LSAT, P = prepared

The premise and the conclusion are logically the same _ i.e. the second conditional is the contrapositive of the first. So the argument puts forward evidence (-P --> -MLSAT) that presupposes what it intends to support (MLSAT --> P).

(E) is out of scope. The Mayor’s motives are not discussed and have nothing to do with the core.

--

(A) is one of the flaws we identified above:

"Infers that a part has a certain quality" = the bridge renovation was a waste of money (our conclusion)

"on the grounds that the whole to which it belongs has that quality" = The Southern Tier Project was egregiously wasteful + the bridge renovation was a part of the Southern Tier Project (our premises)

[keonheecho]

I see that this answer choice is definitely correct considering the other answer choices, and this definitely mentions the flaw in the stimulus. but I'm confused about the "infers" part...normally I learned that we should eliminate answer choices that say "infers" when it doesnt state it as a conclusion. In this case, the conclusion is that the mayor was not telling the truth. I find this to be really inconsistent...how do you know when to eliminate an answer choice based on "infers"?