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 brettb
  • Posts: 14
  • Joined: Mar 29, 2016
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#23194
I am confused on this question. I had trouble diagramming it. I've seen on some other forums/websites the diagram being:

Good Meal :arrow: Good Food :arrow: Good Soil :arrow: Good Farming :arrow: Culture

I don't understand how a couple of the chains are possible. How can Good Meal :arrow: Good Food be possible?

I thought the logical opposite of Bad Food is (not) Bad Food? Therefore, wouldn't Good Food be the polar opposite, something we can't necessarily infer?
 Claire Horan
PowerScore Staff
  • PowerScore Staff
  • Posts: 408
  • Joined: Apr 18, 2016
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#23235
Hi Brett,

I think you are right to point out that food could be neither good or bad and that this problem isn't as logically tight as it could be. However, all of the incorrect answer choices involve a Mistaken Reversal or a Mistaken Negation. They all reverse, in one way or another, the sufficient and necessary conditions. The correct answer, A, is the only one that correctly identifies which clause is sufficient and which is necessary. The problems might not always be written perfectly, but try to just pick the best one!

Good luck!

-Claire
 DAthenour
  • Posts: 16
  • Joined: Sep 21, 2017
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#41035
Hi Powerscore,

I correctly chose choice A for this problem, but am wondering if you could clarify why C is incorrect. I have my conditional chain written as follows:

Good Meal :arrow: Good Food :arrow: Good Soil :arrow: Good Farming :arrow: Cultural Practices

Does the term prerequisite refer to the necessary condition?

Thanks for your help!
 Eric Ockert
PowerScore Staff
  • PowerScore Staff
  • Posts: 164
  • Joined: Sep 28, 2011
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#41558
Hi!

That's exactly right. Answer choice (C) is saying that good soil is required for good farming, or, to diagram:

Good Farming :arrow: Good Soil

This would be a Mistaken Reversal of one of the relationships presented in the stimulus, and so cannot be proven with certainty.

Hope that helps!
 gwlsathelp
  • Posts: 93
  • Joined: Jun 21, 2020
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#86617
Can you diagram the stimulus out completely/line-by-line? I had trouble with the "one cannot ... without ..." phrasing and would benefit from a thorough S&N diagram even though the question and correct answer doesn't actually deal with S&N and only deals with the broad concept of the stimulus.
 Adam Tyson
PowerScore Staff
  • PowerScore Staff
  • Posts: 5400
  • Joined: Apr 14, 2011
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#87288
Happy to help, gwlsathelp! Here's the step-by-step:

First Phrase: Good Meal :arrow: Bad Food (and it's a pretty easy step to convert that to "good food", although "not bad" and "good" are not necessarily the same thing as discussed earlier in this thread.)

Second Phrase: Good Food :arrow: Bad Soil (same issue)

Third Phrase: Good Soil :arrow: Good Farming

Last phrase: Good Farming :arrow: Culture that does all that stuff

In the first two phrases, the use of "cannot" negates the Necessary Condition; if you have one of these things then you cannot have the other thing. In the last two phrases the "without" indicates the necessary condition and we must negate the sufficient condition, which, since it already has a "cannot," becomes positive. So if you cannot have ice cream without chocolate sauce, then if you have ice cream you must have chocolate sauce.

That changing analysis of "cannot" can be very tricky! When coupled with one of those special Necessary Condition indicators (unless, except, until, without) you do the standard approach to those four words, but when those are not present you treat it as "if you are one thing, then you are not the other thing," placing the negation on the Necessary side of the equation. Takes some getting used to, but memorize that rule and you'll have no problems!

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