Logical reasoning PrepTest 101 · Section 3 · Question 10

Incorrect. This answer is a reversal of the first premise.

Incorrect. This answer is a reversal of the second premise.

Incorrect. If the spirit is divisible, then it's imperfect, which is a negation of what we're looking for.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
Material body → Divisible into parts
Divisible (into parts) → Imperfect
Intermediate conclusion - Material body → Imperfect
Main point - Spirit → not Material body

Answer Anticipation:
This Strengthen with Sufficient Premise question has a lot of conditional logic in it, so we should work through that and then find where the gap is. Additionally, there's an intermediate conclusion, so we should identify whether the gap is between the premises and intermediate conclusion, or intermediate conclusion and main point. It almost certainly won't be both, since then we'd need two premises to fill in the logic.

Let's look at the two premises to start. First, we need to discuss the second one, and its overlap with the first one. While the initial statement talks about being divisible into parts, and the second just discusses being divisible, we can treat them as equivalent here, for two reasons. First, what else could something be divided into other than parts? Second, even if there are other ways to be divisible, being divisible into parts is one of them, so it would trigger a sufficient condition of being divisible.

With that noted, we can see that the two conditionals chain together, allowing us to infer: Material body → Imperfect. Since that's the intermediate conclusion, that conclusion is valid, and the gap in the logic must be between the intermediate conclusion and main point.

There, we can see that both talk about a material body, but the conclusion talks about spirit, as well—a concept never raised before. Let's start by taking the contrapositive of the intermediate conclusion to get it to line up with the main point:
not Imperfect → not Material body

Now, to anticipate the answer, we need to find the additional link in the chain that would let the conclusion be built, connecting Spirit and not Imperfect:
Spirit → not Imperfect (→ not Material body)
or the contrapositive
Imperfect → not Spirit

We should also note that not Imperfect is the same as Perfect, so the answer may use that term, instead.

Answer Explanation:
This answer connects the valid intermediate conclusion to the main point. If the spirit is perfect, then it's not divisible, and thus it can't be a material body, as the conclusion states. Since this answer validates the conclusion, it's the correct answer.

Key Takeaway:
Strengthen with Sufficient Premise questions require an answer that makes the conclusion airtight. As such, if there's an intermediate conclusion and a main point, the gap in the logic will almost certainly exist in only one of those locations because if both were based on an assumption, then the answer would have to establish two connections. While theoretically that could happen, in practice, it almost never does (we can think of maybe one example of it).

Incorrect. The assumption of the argument is that the spirit is perfect, and it being indivisible wouldn't guarantee that it's perfect (that would be a negation of the second premise), so this answer doesn't justify the conclusion.