QUESTION TEXT: At Tromen University this semester, some students…
QUESTION TYPE: Sufficient Assumption
CONCLUSION: French literature 205 SOME not French literature majors
REASONING:
French lit 205 SOME biology 218 –> Biology major
ANALYSIS: Normally, in a sufficient assumption question I say to identify the conclusion, split it apart, and fill in the evidence. That mostly works here, but there’s one hitch: both the conclusion and the evidence use “some” statements.
But let’s ignore that for now, and just try splitting and adding. I’ll use arrows, but they don’t necessarily mean conditional statements:
French 205 not French literature
French 205 –> biology 218 –> biology major –> not French literature
Easy, right? We just have to add “not French literature” to the end of the statement from the reasoning. However, we do need to add the “some” statement back in:
French 205 SOME biology 218 –> biology major –> not French literature
I wouldn’t do this in two steps myself, by the way: I only split it out to make the steps in the process clearer. But, you might be wondering, how does this prove the conclusion? Well, “some” statements transfer from left to right. So, from the diagram above we can say:
- Some French 205 students are biology majors, and
- Some French 205 students are not French literature majors
This second one is true because of the sufficient assumption we’re making: no bio major is a French lit major.
Unusually, the reasoning in this argument already lets us draw a conclusion: “some French literature 205 students are biology majors”. When a “some” statement connects with a sufficient condition, you can always transfer the ‘some” statement to the necessary condition as well.
Note: you might wonder, why didn’t we add “Biology major SOME not French literature majors” to the end? After all “SOME not French literature majors” was in the conclusion. The reason we don’t do this is because some statements never go to the right hand side of conditionals. They only go on the left hand side. So, the “SOME” in the conclusion goes at the start of the statement. That’s how it can transfer from left to right across the whole chain:
French 205 SOME biology 218 –> biology major –> not French literature
___________
- This doesn’t tell us much. Even though French lit 205 is required for French literature students, there could be students from other majors in the class. (In fact, there are. We know from the stimulus that some are biology majors.)
- This might seem tempting, but in fact we could already deduce that the French lit 205 students in Biology 218 were biology majors. After all, every student in that class was a biology major. So we don’t need to ban non-biology students from the class: we already know there were none.
- Raw numbers don’t matter. Even a single student can be “some”, and thus prove the conclusion.
- Same as C. Raw numbers don’t matter when dealing with “some” statements. Even a single example is enough to prove something.
- CORRECT. This is the assumption I described in the analysis. If both majors are mutually exclusive, then those biology majors in French 205 can’t also be French majors.
Recap: The question begins with “At Tromen University this semester, some students”. It is a Sufficient Assumption question. To practice more Sufficient Assumption questions, have a look at the LSAT Questions by Type page.
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