Self-study
Economist: Support No economic system that is centrally planned can efficiently allocate resources, and Support efficient allocation of resources is a necessary condition for achieving a national debt of less than 5 percent of Gross Domestic Product (GDP). ██ ███████ ████ ███ ██████ ████ █ █████████ ███████ ███████ ███ █ ████████ ████ ████ ██ ██ █████ █ ███████ ██ ████
The Contrapositive Argument
The language in the stimulus and answer choices is super thorny throughout, but at its core this question is a test of the contrapostive argument form.*
English
P1: Central systems can’t be efficient.
P2: But you need to be efficient to have [small debt].
________
C: Central systems don’t have [small debt].Logic
P1: Central → /Efficient
P2: Small Debt → Efficient
(P2 Contra: /Efficient → /Small Debt)
________
C: Central → /Small Debt
A lot of the time, just recognizing this as a valid conditional chain of some kind will suffice to isolate the correct answer. To my mind, the ideal approach to this question would be to roll into the answers with that vague notion in mind, eliminate (A) and (C) at least, then loop back around for a more disciplined breakdown of the stimulus (for which I’d highly recommend jotting down some notes).
*Technically, the stimulus uses the contrapositive argument form in the context of a conditional chain. The main point, though, is that it does contrapositive stuff.
25.
The pattern of reasoning exhibited ██ ███ ███████████ ████████ ██ ████ ███████ ██ ████ █████████ ██ █████ ███ ██ ███ ██████████
a
Not all mammals ███ ███████ ██████ ███████ ████ ███ ███████ ███ ████ ████ ██████
Negating an “all” claim yields a “some” claim. Here, “not all mammals are [blah]” translates to “some mammals are not [blah].”
The stimulus features no “some” claims – this quantifier mismatch suffices to eliminate (A). You should aspire to recognize this rapidly and without the need to diagram anything.
b
All of the █████ █████████ ███ ████ ██ █████ ███ █████████ ████████ ███████ ████ ████████ █████ ████ █████ █████ ██ █ █████ █████████████ ██ ████████████ ███ █████ ███ ██ ████ ██████ ██ ███ █████ ██████████
This matches the stimulus’ contrapositive argument form:
English
P1: Rural districts don’t have lots of automobiles.
P2: But you need lots of automobiles to have pollution problems.
________
C: Rural districts don’t have pollution problems.Logic
P1: Rural → /Autos
P2: Problems → Autos
(P2 Contra: /Autos → /Problems)
________
C: Rural → /Problems
Note that I’ve re-ordered (B)’s claims to mirror the order used in the stimulus. That’s totally fine since the underlying logical structure is the same. That different order is for sure part of what makes (B) hard to recognize, though. Get used to it!
c
All of the █████████ ███ ███████████ ███ ████ ██████████ █████ ███ ██████ █ █████ ██████ ██ ███████ ████ ███ ██████ ████ █████ ██████ █ █████ █████ ██ ████████ ██ ██ ██ █████████
The terms “most” and “unlikely” are mismatches in quantity (and likelihood) with the stimulus, which solely features “all” claims (and “definite” claims). These suffice to eliminate (C). You should aspire to recognize them rapidly and without the need to diagram anything.
d
All rock stars ███ ███ ██████ ████ █████ ███ ██████ ██████████ ███ ███ ████ █████ ████ █████ ███ ██████ █████████ ███████ ███████ ███████ ████ ███ █████ █████ ███████ ██████████ ████ ███████ ████ █████████ █████ ███████ █████████ ██ █ █████████ █████████ ██ █████ █ ██████ ████ █████
(D) is wrong for two main reasons. First, there’s a subtle term switch from “receiving profits over and above regular royalties” and “receiving large regular royalties.” Those concepts aren’t the same, so the logical chain (D) attempts has a broken link there. Spotting this spares you the need to diagram.
If you miss that and do diagram, though, (D) is wrong because it exhibits a straightfoward conditional chain that doesn’t do any contrapositivey stuff. Here’s the logic:
Logic
P1: Famous → Record
P2: Record → Profits
________
C: Famous → Profits(ish)
e
Every mutual fund ███████ █████ ███████ ███ ██████ ██ ██████ ████████████ ███ ██ ███ ███ ██████ ██ ██████ ███████████ ██ ███████ ██ █████ ██████ ████ ████████ ███ ████ ████████ ████ ██ ██████ ████ ███████ ██ ███████ ██ ████████ ███ ██████ ██ ██████ ████████████
(E) is wrong because of a number of conceptual mismatches between terms. Making clean links between conditional statements means terms need to overlap from one claim to the next. (E) jumps around between the similar sounding, but nevertheless distinct concepts of managers, insiders, people-who-are-known-to-managers, and people-who-are-known-to-insiders.