Weird LSAT Blog question Forum

[Captain Rodeo]

Ok, I was perusing LSATBlog and I saw a question from a reader:

"I was trying to come up with an example for "the only" as a sufficient condition indicator but was unable to. Is "the only" not a necessary condition indicator?

For example,

The only time I woke up before 5 a.m was when I took the LSAT.

Here, "the only" relates to when I took the LSAT. The sentence could be re-written as "If I had woken up before 5 a.m. then I must have been taking the LSAT that day".
Could you please clarify? Thank you "

Steve clarified:



"Hi Pax,

"The only" is a sufficient condition indicator.

Example:

"The only girls I date are models."

This means:

If I date a girl, she must be a model.


Your sentence above, in if-then format, should be:

If I woke up before 5AM, it must have been to take the LSAT.

Your rewritten version is incorrect - it's a mistaken reversal.

Hope this helps!"

I'm just wondering about the first sentence the OP wrote : "The only time I woke up before 5 a.m was when I took the LSAT." I'm pretty sure when Steve wrote "Your sentence above, in if-then format, should be: If I woke up before 5AM, it must have been to take the LSAT." that he was referring to this original sentence.

However- how would the OP's original sentence be written in FL? It has "the only" and "when" which are both sufficient condition indicators. Could it be a biconditional?? (when I took the LSAT I woke up at 5 AM... if I woke up at 5 AM I took the LSAT) Maybe I'm missing something.

Thanks TLSers!

P.S.- the link is here (http://lsatblog.blogspot.com/2009/10/wo ... ssary.html)

[vegso]

No it's not bi conditional. I dont know if im any good at explaining this stuff but

"the only time i woke up before 5am was when i took the lsat"

Dont try to look for the keywords so much as understanding what the sentence says. So lets take a cheating example because humans are inherently better at detecting cheaters than they are at logic in general

"The only time I can get into a bar is when I am 21 or older"
This becomes "If i am in a bar, then I am 21 or older"

like "if i am 21 or older, then i must be in a bar" obviously doesnt make any sense given the original and same goes to bi conditional stuffs

Or abstract it even more, the only time A happens is when B happens. Therefore B is necessary for A to happen

does that help at all?

[Captain Rodeo]

Sweet response! Yes that helps, thanks a lot!