June 2010 LSAT Section 5 Question 18

Based on the passage, it can be concluded that the author and Broyles-González hold essentially the same attitude toward

Mia on September 4, 2021

Question 2. Sufficient in Common

In question number 2 we say that we have sufficient in common, which satisfies Rule #2. We have the problem laid out as such: P1: SPP-m-CNG P2: PP-s-CNG P3: CNG -> WLG We satisfy rule 1 by having the S->N statement, but I don't understand why we satisfy rule 2. In this scenario, P1 and P3 don't share a sufficient. Are we assuming that we can swap the SPP-m-CNG to CNG-s-SPP which is why they have the sufficient in common? If so, why can't we do this for all other examples shown to us in the theoretical drills?

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Stephanie on May 5, 2022

I also have this question. Can someone answer please?

Naryan-Shukle on May 6, 2022

Hi @Mia,

So these Rule #1 and Rule #2 exercises are designed to get you thinking about S&N in the right way. When Mehran says "sufficient in common," he is basically asking " can we create chains?"

If I have these two chains:

A--->B

B--->C

I am looking at this as if I were a kid doing crafts, trying to make a whole long chain or snake. But the rule of this game is that I can only hook things together if the letters are the same. With this example, I CAN link them up:

A--->B--->C

I simply linked them up through the (B). And Quantifiers are no different.

SPP--m--CNG
CNG--->WLG

Do you see any common variables where I could glue my chain together? I do.

SPP--m--CNG--->WLG.

This gets us to one of our possible answers. Try not to take the statement "link the sufficient" too literally. It's a trick to help wrap your head around the concept. What's important is that you understand you can link things together through common variables. Just remember that if you flip statements around to try and link them up, that you do your contrapositives properly.

This concept is a very mind bending one, so don't feel defeated if it takes you a while to understand it. These message boards aren't the best medium for teaching this concept, either. Try checking out my Office Hour on Sufficient and Necessary (you can filter for Naryan to find all my lectures.) Additionally, I am more than happy to take you in a private lesson to try and better explain these concepts.

Hope this helps at least a bit! If you have any more questions don't hesitate to ask.