3.16 - Sufficient Assumption

Next, we're covering Sufficient Assumption questions. These questions test our

You can think of these questions as the strongest of all Strengtheners. Your job is to identify an answer choice that proves the argument's conclusion.

Sufficient Assumptions tend to look something like this:

• The conclusion drawn in the argument follows logically if which one of the following is assumed?
• The ethicist's conclusion can be properly drawn if which one of the following is assumed?
• Which of the following, if true, would allow Jason's conclusion to be logically drawn?

You can always predict the answer to these questions. You just need to figure out what would close the gap between the argument's evidence and conclusion and then go find that gap-filler in the answer choices.

Let's work through some examples.

Examples

June 2007 PrepTest, Section 2, Question 6

First, we're tackling Question 6 from Test J, Section 2:

An undergraduate degree is necessary for appointment to the executive board. Further, no one with a felony conviction can be appointed to the board. Thus, Murray, an accountant with both a bachelor's and a master's degree, cannot be accepted for the position of Executive Administrator, since he has a felony conviction.

Let's break this down piece by piece. First, we're provided with a requirement for joining the executive board: an undergrad degree. Then, we're given another: no felony convictions. Makes sense that we'd only want educated folks without criminal histories on the board. Then, we're told that Murray can't be accepted for Executive Administrator because he has a felony conviction, even though he has a bachelor's and a master's.

Classic SA structure, here. Give some requirements for thing A, then, tell us so-and-so can't be thing B because they don't meet one or more of thing A's requirements. In this case, thing A is joining the executive board whereas thing B is becoming Executive Administrator. The word executive doesn't necessarily conflate the two.

So, what would guarantee our conclusion that Murray can't be Executive Administrator? Well, if Executive Administrator was a board position, that would do it. Or even more simply, if the EA job has the same requirements as any board position. That's going to be our answer.

And there it is in answer choice B: "Only candidates eligible for appointment to the executive board can be accepted for the position of Executive Administrator." Cash money.

Notice how this assumption completely fills the thing-A-thing-B gap I mentioned earlier? That's all you need to do: identify the gap and go fill it up.

Let's try another, Question 13 from the same section as before:

Standard aluminum soft-drink cans do not vary in the amount of aluminum that they contain. Fifty percent of the aluminum contained in a certain group (M) of standard aluminum soft-drink cans was recycled from another group (L) of used , standard aluminum soft-drink cans. Since all the cans in L were recycled into cans in M and since the amount of material other than aluminum in an aluminum can is negligible, it follows that M contains twice as many cans as L.

Love these mathy ones that push us a bit—who doesn't love a challenge?

Start with the conclusion: M contains twice as many cans as L. So, double the total number of cans—we need to prove that.

Next, consider the evidence: Cans don't vary in the total aluminum per can and the rest of the can's content is negligible. 50% of the aluminum content of group M was recycled from group L, not necessarily in terms of number of cans, though. But, 100% of L's cans become M cans.

Let's use round numbers to simplify this. Imagine there are 100 cans in M. That means exactly 50 are made of aluminum recycled from L. To guarantee that M's number of cans (in this case, 100) is exactly double that of L, we'd need to recover 100% of the aluminum from an L can on its way to becoming an M can. That's my prediction.

Boom, there it is in answer choice C: "All of the aluminum in an aluminum can is recovered when the can is recycled."

Notice how similar this question is to the one we covered earlier. We have a thing A—aluminum content—that ends up conflated with a thing B—number of cans. It's easy to let your eyes glaze over and treat these independent variables as essentially the same thing. Read carefully.

Looking for a more in-depth explanation? Click the link above where we cover it in full.

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That does it for Sufficient Assumptions. Catch you next time where we're working through Strengthen questions.