LSAT 90 - Section 4 - Question 25

This is a Fill in the Blank question.

The question stem says “the conclusion of the argument follows logically if,” which should remind you of Sufficient Assumption questions. And sure enough, there is a premise indicator “since” right before the blank. We are looking for a premise to fill in this blank such that the conclusion follows logically. Once you figured this out, hopefully you will soon see that the rest of this question is just a pure exercise in formal logic. In fact, you drilled this specific argument form in the core curriculum. This is not to say that this is an easy question, only that there is a fair amount of predictability in Logical Reasoning.

The stimulus says that most of the members of Bargaining Unit Number 17 of the government employees’ union are computer programmers. I am going to refer to this as 17. And the relationship between 17 and computer programmers is not that of complete subsumption, but a most relationship.

17 —m→ computer programmers

This is the only premise, and the question jumps straight to the conclusion. Thus it is certain that some of the government employees who work in the Hanson Building are computer programmers. In other words, there must be at least one overlap between these groups.

Hanson ←s→ computer programmers

So the conclusion is a some relationship, but the premise gives us a most relationship. If you recall from the core curriculum, you can use a most relationship to get to a some relationship by supplying another most relationship or something stronger. Unfortunately, all of the answer choices are most statements. So while you can use the process of elimination, it is faster to recall how you can build the correct premise to arrive at the conclusion we want.

The way to do that is to supply this missing premise:

17 —m→ Hanson
17 —m→ computer programmers
_______________
Hanson ←s→ computer programmers

How does this argument work? Say there are three members in 17, and most of them work in the Hanson building. This means I have to take at least two members and scoop them into Hanson. But I also have to take most of 17, at least two members, and scoop them into computer programmers as well. Then these two scoops must intersect by at least one member. And this is exactly what Correct Answer Choice (D) gives us. It says most of the members of Bargaining Unit Number 17 work in the Hanson Building.

Answer Choice (C) says most of the government employees who work in the Hanson Building are members of Bargaining Unit Number 17 (Hanson —m→ 17), so we can chain this to our premise to get:

Hanson —m→ 17 —m→ computer programmers

But two most statements chained up like this don't yield the desired conclusion. Say we took most members of Hanson and dropped them into 17. But 17 could be a humongous set and Hanson could be a tiny set, so this is just a drop in the bucket. Now if we scoop most of 17, there is no guarantee that we will capture a member of the Hanson set. We could, but we could just as well not.

If this does not make sense, you can either review the core curriculum or, better yet, try assigning numbers. Assign a small number for Hanson and a large number for 17 and see how you can make the two most relationships true while making the conclusion that Hanson ←s→ computer programmers false.

Answer Choice (B) is kind of interesting. It says most members of the executive committee of Bargaining Unit Number 17 work in the Hanson Building. Who are these executive committees? We can infer that the executive committee of 17 is some subset of 17. But this subset (the executive committee) could be very small. Nothing in (B) tells us anything about the size of the executive committee. If it's very small, then the fact that most of them are in Hanson merely amounts to a claim that some (not most) members of 17 work in Hanson. That's not powerful enough. Contrast this with the much more powerful most relationship in (D), where we did not carve down into the subset first before supplying the most relationship. (D) just outright said that most of 17 belongs to Hanson. (B) says first, carve down into a subset of 17. Most of that subset belongs to Hanson.

Answer Choice (A) says most of the government employees who belong to Bargaining Unit Number 17 but are not computer programmers work in the Hanson Building. This is really bad. (A) is looking at the intersection of 17 and not computer programmers. (A) takes a most cut of that set and puts them into Hanson. But that's useless because this intersection is already a set of people who are not computer programmers. How does that help us establish that some people in Hanson are computer programmers?

Answer Choice (E) says most of the people who work in the Hanson Building are government employees. So who are the government employees? Well, they are a superset of 17. Remember, 17 stands for Bargaining Unit Number 17 of the government employees' union. So everyone in 17 is a government employee, but government employee is a superset of 17.

(E) says to take the people in Hanson and drop most of them into the government employee superset. Okay, but where do they land in this large government employee superset? We don't know. Will they even land in the 17 subset? No idea.