PT18.S2.Q23 - teachers are effective only when

catatac7

http://7sage.com/lsat_explanations/lsat-18-section-2-question-23/
I'm having trouble translating the "not until" statement. Until is "negate sufficient" but the "not" cancels the negation from the until rule so then it reads just like an if then. Is it ok for me to go ahead and memorize that when group 3 and 4 indicators are used this way in the beginning of a sentence they cancel each other and it reads like an if then?

c.janson35

I'm weary about saying that you can do that in all situations, yet someone else may be able to better speak to it than me.

I think if you aim for an intuitive understanding of this sentence then it might help you to see the relationship better. "Not until teachers have the power... Can they enable their students to make own decisions." So the sentence is making a necessary confusion out of the PMDC variable, because it is saying "not until" that occurs can SMOD. Thus, because it is a necessary, it reads like "if SMOD, then it must be true that teachers PMDC".

To break it down in more manageable bits:

Not until X can Y occur.

This is saying that if there is no X, then there is no Y: /x--->/y, or the contrapositive: y--->x.

Again, x is the necessary condition, because the "not until" is creating a necessary condition out of x, which is what we have in our contrapositive.

Finally, if it is easier to think of in terms of "unless" for you, it's a pretty intuitive English translation:

"Not until teachers have PMDC can they enable SMOD"

Can be with unless as:

"Unless teachers have PMDC, students will not be able to MOD"


Hope this helps!

catatac7

This helps tremendously. Until and unless are both group three and introduce necessary or negate sufficient. I think the "not" in front of the until is redundant. I see that by the example using the unless statement. Saying "not unless" would also be redundant.

Turns out I was confused. I'm glad I reached out for help. Thank you.

nicole.hopkins

@catatac7 said:
I think the "not" in front of the until is redundant.

I agree!

c.janson35

Grammarly speaking, you couldn't just remove until from the sentence because it would no longer make sense. You could move it to the "students" clause and still capture the same meaning though, which would make until function more closely to unless. So, and I'm worried I'm inching closely into "THAT guy" territory, I don't think the not is really redundant lol.

nicole.hopkins

@c.janson35 That's true—you'd need to insert the "not" into the second part of the sentence.

catatac7

Thanks for the clarification! It's more intuitive to see it as introducing the necessary than to negate sufficient and then also negate the necessary. But I see it both ways now.