- Fri Apr 03, 2020 11:20 am
Let's write that out and see what we have! "Walter's claim to a potential employer that he had done volunteer work was a lie. Walter had worked without pay in his father's factory, and he did not use the phrase "volunteer work" in an attempt to deceive the interviewer."
In that situation, sim.LSAT, the conclusion that Walter lied would not be valid because there would be no reason to believe that he had lied. In the absence of the sufficient condition (intent to deceive or failing to clarify a misinterpretation), we cannot know whether or not the necessary condition occurs, so concluding that it did occur is unsupported. Also, the answer would no longer "conform to the principle" because it wouldn't be following the rule in the principle. It no longer has anything to do with the principle, really.
Necessary conditions aren't things that are always true. They are things that must occur IF the sufficient condition occurs, and which MAY occur even when the sufficient does not. The only time you can prove that a necessary condition occurs is when the sufficient condition occurs.
The question of whether a claim is "valid" is not a question of whether that claim is objectively true. It's about whether that claim is logically supported by one or more premises. If I say "I'm happy", we cannot say whether my claim is valid or not, because it was not connected to any supporting statements. But if I say "I am always happy when I am working, and I am working right now, so I am happy," then we can say my claim is either valid (logically supported by the premises) or invalid (NOT supported by the premises). It doesn't matter whether it is true that I am always happy when I am working (I usually am, but not always), because we aren't evaluating truth on the LSAT. What matters is whether those premises provide sufficient support to reach that conclusion (they do - it's a valid argument). So we cannot say that the conclusion "Walter did lie" is a valid claim unless we evaluate it in light of whatever premises were used to support it.
I hope that helps clear things up!
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
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