PT74.S1.Q17 - How the pigment known as Han purple

beepbooptroupe

I understand that A is right because it counters a possible objection that Han purple and white glass were produced independently of each other, in different places.

But I thought that C also nullified a possible objection, so I'm having trouble understanding why it's ultimately wrong. I chose C because I thought it countered the reverse explanation: that white glass was the accidental effect of Han purple production. If only very few people knew how to make Han purple and then created white glass later (by accident or not), then how would white glass have become so common, like the stimulus says? I don't think it's a huge jump to say that if very few people knew a technique for making Han purple/white glass, then both were probably not very common. So this shows that an alternative explanation would not be consistent with the fact that white glass was common. Doesn't C, like A, also counter an alternative explanation?

Is it different from A because when we negate it, and say that a lot of people knew how to make Han purple, that negation doesn't clearly weaken the argument?

Any further clarification on why C isn't really doing the same thing as A (weakening an alternative explanation) would be very helpful!

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A furthers the connection between Han Purple and the Common Type of White Glass. The premises tell us that the first connection is ingredients and the second is similar production methods. A gives us a third connection--location. A doesn't just counter a possible objection, it operates as a third premise akin to the first two in support of the conclusion.

C does not further the connection between Han Purple and the Common Type of White Glass. C merely states that very few people knew how to make Han Purple. All we can infer from this are a few strange scenarios that do not really strengthen or weaken the argument. For instance, if the production methods of the Common Type of White glass made by presumably many workers was known to those many workers, and our arguer is proposing that Han Purple came as a fortuitous accident during Common Type of White glass-making, C proposes that the accident was not only quite rare but that communication about it was scarce amongst the workers or kept secret or regarded as disinteresting to most workers. As for your interpretation of what C objects to, bear in mind that from the stimulus we have no reason to presume the means by which the Common Type of White Glass was made is in question, only the synthesization of Han Purple during that era is a mystery. As such, we could not need to disprove an objection such as, "Han Purple actually preceded White Glass production there and in fact White Glass production was an accidental consequence of Han Purple making." This seems very unlikely to be tenable just based on the stimulus unaltered as Han Purple is the mystery while the Common Type of White Glass is seemingly well understood.

In a way, yes, it is different from A because when we negate it, and say that a lot of people knew how to make Han purple, that negation doesn't clearly weaken the argument. As for the psychological approach to Strengthening questions: Reserving negation strategy for necessary assumption questions seems effective. For Strengthening questions, looking for what bolsters the bridge between Premise and Conclusion works well.