dannybang wrote:For #20, do you diagram the conditional reasoning? How would you approach this problem?
This is precisely how I do No. 20 on test day:
In order to find the response option with the most similar pattern of reasoning, first, I have to be clear on the pattern of reasoning contained in the initial argument.
All A (moral actions) are B (the keeping of agreements)
All B are not more than C (acts securing mutual benefits)
All B are not A
Therefore,
Some C are not A
Notice, I am not sure exactly how LSAC wants me to interpret “not more than” in syllogism terms, so I didn’t do it (although it looks like All B are C is going to suffice considering the logic pattern). I left it as stated and I’ll make that determination once I see the response options. But, I do have a clear view of the pattern. On to the response options.
Choice A? All A (calculators) are B (computers). All B are C (auto reasoning devices). All C are Not A. [Already different]. Therefore, Some C are Not B. Strike it.
Choice B? All A (exercise) is B (beneficial). All B are C (promote health). All B are Not A. Therefore, Some A are Not C. Close but no cigar (the conclusion is backward). Strike it.
Choice C? All A (metaphors) are B (comparisons). Not All B are C (surprising). [Already pretty different]. All A are C. Therefore, Some B are Not A. This does not look like it. Is it some twisted version of it? I am not going to sit and stare and try to figure that out now. First I will look for a good match in the two remaining response options. If I do not find one, I’ll come back and stare at this.
Choice D? All A (architecture) is B (design). All B is C (art). All B is Not A. Therefore, Some C is Not B. Close again, but not quite it. Strike it.
Choice E? All A (books) are B (texts). All B are C (documents). All B are Not A. Therefore, Some C are Not A. It took a while but I found a perfect match. Mark it. Good thing I did not waste a lot of time staring at Choice C.