LSAT and Law School Admissions Forum

Get expert LSAT preparation and law school admissions advice from PowerScore Test Preparation.

User avatar
 MordecaiSmith
  • Posts: 3
  • Joined: Oct 30, 2024
|
#110247
In the 6th principle it claims that "Any combination of an arrow and double-not arrow in succession will yield an inference" and it uses the example "A :arrow: B :dblline: C" to prove this point with its inference being "A :dblline: C". This makes complete sense to me.

To test the theory that any combination of an arrow and double-not arrow will yield an inference I wrote out an alternative to the example statement as "A :larrow: B :dblline: C" and the inference, "C :dblline: A", can't be true. For example there's one possibility that "C :some: D :arrow: A"

To me this disproves that "Any combination of an arrow and double-not arrow in succession will yield an inference".
Is there something I'm missing here?
User avatar
 Dave Killoran
PowerScore Staff
  • PowerScore Staff
  • Posts: 5959
  • Joined: Mar 25, 2011
|
#110253
Yes, you are missing something! I think you expected another power arrow inference like the one you cited, but in this case, let's walk through it and watch what happens:

  • We start with: A :larrow: B :dblline: C

    Here we want to start with either A or C to begin making an inference, and it's easier to start with A since the C/B relationship is a double-not arrow.

    Starting at A then, how do we "go backward" against the arrow to get to B? Well, if all Bs are As, then we know for sure that at least some As are B, and so what "goes backwards" is A :some: B.

    We can then attach that to the B/C relationship to get: A :some: B :dblline: C.

    Following the Some Train then, we can start at A and arrive at C, leading to the following inference:

    A :some: C

This is actually an inference that we've seen before on the LSAT, so it's one you want to know (and you'll see more of it--that's a long chapter :-D ).

Thanks!
User avatar
 MordecaiSmith
  • Posts: 3
  • Joined: Oct 30, 2024
|
#110272
That does help thanks!
User avatar
 MordecaiSmith
  • Posts: 3
  • Joined: Oct 30, 2024
|
#110273
Dave Killoran wrote: Wed Oct 30, 2024 4:12 pm Yes, you are missing something! I think you expected another power arrow inference like the one you cited, but in this case, let's walk through it and watch what happens:

  • We start with: A :larrow: B :dblline: C

    Here we want to start with either A or C to begin making an inference, and it's easier to start with A since the C/B relationship is a double-not arrow.

    Starting at A then, how do we "go backward" against the arrow to get to B? Well, if all Bs are As, then we know for sure that at least some As are B, and so what "goes backwards" is A :some: B.

    We can then attach that to the B/C relationship to get: A :some: B :dblline: C.

    Following the Some Train then, we can start at A and arrive at C, leading to the following inference:

    A :some: C

This is actually an inference that we've seen before on the LSAT, so it's one you want to know (and you'll see more of it--that's a long chapter :-D ).

Thanks!
Just realized principle number 7 explains this lol, thanks again

Get the most out of your LSAT Prep Plus subscription.

Analyze and track your performance with our Testing and Analytics Package.