Sufficient & Necessary Review - The Only

Posted on

Last week we did a refresher on how to diagram Sufficient & Necessary questions with “only” in them. Remember? This should be ingrained in your LSAT prep by now. “Only” introduces the necessary condition. But, we discussed briefly not to get “only” mixed up with “the only.”

The only” introduces the sufficient condition. You want to look at “the only” as “it’s the only one,” meaning whatever “it” is, it will be the only thing with a certain characteristic. So “The only A is B,” means if something is an “A,” it must also be a “B.”

Let’s look at a few examples:

(1) “The only way out of the labyrinth of suffering is to forgive.” –John Green

Sufficient condition: “way out of the labyrinth of suffering”

Necessary condition: “to forgive.”

We can rewrite this: If it is the way out of the labyrinth of suffering, then it is to forgive.

WLS ==> F

not F ==> not WLS

(2) “Laughter is the only cure for grief.” –Robert Fulghum

Sufficient condition: “cure for grief.”

Necessary condition: “laughter”

We can rewrite: If it is a cure for grief, then it is laughter.

CG ==> L

not L ==> not CG

(3) “Books are the only true magic.” Alice Hoffman

Sufficient condition: “true magic.”

Necessary condition: “books”

We can rewrite: “If it is true magic, then it is a book.”

TM ==> B

not B ==> not TM

See? There is nothing to it! Just make sure to take your time and distinguish between “the only” and “only.” You don’t want to lose points just because you failed to notice one article! Keep up your LSAT prep!

Happy Studying!

Updated on Aug 18, 2016