Self-study
Political theorist: The vast majority of countries that have a single political party have corrupt national governments, but some countries with a plurality of parties also have corrupt national governments. ████ ███ █████████ ████ ███████ ████████ ███████████ ████ ██ ███████ ████████ ██ ███ ████████ ██ █████ ████████████
Some & Most Before All
This question is pretty doable with or without formal diagramming, but it’s a nice excuse to practice anyway. Ideally, you should be familiar enough with the valid argument forms that you can preemptively draw two valid inferences:
English
P1: Most single-party countries are corrupt.
P2: Some plurality countries are corrupt.
P3: All corrupt countries are weak.
________
Inf 1: Most single-party countries are weak.
Inf 2: Some plurality countries are weak.Formal Logic (Domain: Countries)
P1: Single –most→ Corrupt
P2: Plurality ←some→ Corrupt
P3: Corrupt → Weak
________
Inf 1: Single –most→ Weak
Inf 2: Plurality ←some→ Weak
We get the first inference by linking premises 1 and 3, putting most before all. We get the second inference by linking premises 2 and 3, putting some before all.
12.
If all of the political ██████████ ██████████ ███ █████ █████ ███ ██ ███ █████████ ████ ████ ██ █████
a
Every country with ████ █████ ██████████ ███ █ ██████ █████████ ██████
(A) confuses sufficiency and necessity and changes “most” to “all.”
We can validly infer that most single-party countries have weak local governments. (A) is a backward version of that claim with “every” in place of “most.”
b
Some countries with ████ █████ ███████████ ████ █ █████████ ██ █████████ ████████
This appropriately puts some before all:
Some plurality countries are corrupt. All corrupt countries are weak. Therefore some plurality countries are weak.
It’s worth noting also that “some” claims are reversible.
c
Some countries with ████ █████ ███████████ ██ ███ ████ ███████ ████████ ████████████
This could be false. A world in which (C) is false is one where all weak countries are corrupt. That’s us negating (C).
The stimulus gives us the converse of that claim. It tells us all corrupt countries are weak. Those two claims are consistent with one another – they can both be true at the same time.
That is, just because all corrupt countries are weak, that doesn’t mean there are some weak countries that aren’t corrupt.
d
The majority of █████████ ████ ████ █████ ███████████ ████ █ ██████ █████████ ██████
(D) is a backward version of one of the valid inferences. As shown in the analysis section, we can validly infer “most single-party countries are weak” from the premises. (D) says that in reverse.
e
Fewer multiparty countries ████ ████████████ █████████ ████ ████ █████ ████████████
We can dismiss (E) for two different reasons, both of which are common LSAT themes. First, our premises only give us information about proportions, whereas (E) compares numbers. Even if a higher proportion of single-party countries are weak than multi-party countries, but that doesn’t mean the number of weak single-party countries is higher – there might be way more multiparty countries in general.
Also, “some” and “most” claims can both technically include “all”-type scenarios. That is, the claim that “some multiparty countries are weak” leaves room for the possibility that all multiparty countries are weak. So there’s not even a guarantee that a higher proportion of single-party countries are weak than multiparty countries.