Page 246 "if and only if"

[salty]

Hi,

On page 246 "if and only if" condition, is "A if B" presented as "B A" actually logically different from "A only if B" presented as "A B"? or is the difference illustrated only for the sake of LSAT rules? i.e. they are inherently the same but just for the sake of differentiating in LSAT rules you just present them as so. I try to grasp the inherent meaning as if there is any subtle difference in meaning between saying just "if" and saying "only if" but I couldn't figure out and just decided to memorize them as a mathematical formula.

I thank you in advance for your time and help.

[Dave Killoran]

Hi Salty,

Thanks for the question! They are two different statements, with very different meanings. One has A as the sufficient condition, which mean that if A appears then B must also appear, and the other has B as the sufficient condition, which means that if B appears then A must also appear. So, while they would both result in A and B appearing, what activates that result is very different.

Does that help explain that idea? Please let me know. Thanks!