bp shinners wrote:In that third sentence, "after all" is being used to state a possibility that would explain how the conclusion might be true. It is a premise, but it's not a fact supporting a conclusion - rather an explanation of how the conclusion is possible.
But the conclusion is also an explanation (of the evidence) on its own. We have evidence X that is explained by Y which, in turn, is explained by A or B. How do we decide which explanation (Y, or A/B) is the main conclusion? Kaplan solution is based solely on the fact that "after all" cannot be followed by the conclusion, therefore, Y must be the conclusion.
While this might be a good lesson about "after all" in particular, it opens the door to another topic. Look at this:
#1: Newly discovered evidence shows X. Therefore, Y happened. After all, Y could have been caused by either A or B.
#2: Newly discovered evidence shows X. Therefore, Y happened. Y could have been caused by either A or B.
#3: Newly discovered evidence shows X. Therefore, Y happened. Thus, we conclude either A or B must have happened.
Are all three arguments about the same? I don't see much difference. Do you think the main conclusion is the one that directly connected to the main evidence (i.e. Y), or is the one that is heavily emphasized (e.g. "we conclude...") ?
My point is that perhaps the conclusion would be more correctly determined by how close it is related to the main evidence presented. If the argument explains something, and then proceeds by subsequent inference(s), then all those inferences are not the main conclusion (as long as they are not directly connected to the original point). The solution of Kaplan did not emphasize this, and merely relied on "after all" structure (which to me seems questionable). Here are two examples:
A law school X requires LSAT scores to be above 160. A person Y was admitted to X.
1) Therefore, Y must have spent at least 3 months practicing on LR. After all, his LSAT score is above 160.
2) Therefore, his LSAT score is above 160. After all, Y must have spent at least 3 months practicing on LR.
In both cases the main conclusion is that Y's LSAT score is above 160 (because this is directly related to the the main evidence). The point that Y must have spent at least 3 months practicing on LR is an inference, that is not directly related to the main evidence.
What do you think?