parsing

[commandercranky]

Is there a difference between "if" and "if and only if"?

If you think so, please explain.

Comments

lawyer grammar queen

[bing_crosby]

emphasis only, I would think. And let me test this out-- like "or" vs "and/or," it's more vague than the shorter version while claiming to be more specific.

Re: lawyer grammar queen

[commandercranky]

I wasn't sure when I posted this, but I've thought about it more and I think there is an important difference. I disagree that the longer version is vague. It's the shorter version that is less specific.

For example (to borrow from vampyrecat), imagine two different rules:

1. If you clean your room you get a cookie.

2. If and only if you clean your room you get a cookie.

Under rule 1 there might be other ways to get a cookie, but we know this is one way. Under rule 2 you're stuck - you better clean your room if you want a cookie, because there's no other option.

Re: lawyer grammar queen

[bing_crosby]

ok, point taken. didn't take much.

Re: lawyer grammar queen

[i_am_electro]

As someone who thinks like a robot sometimes, you are correct. If and only if is very important when trying to limit cookie distribution.

Re: lawyer grammar queen

[never_the_less]

I want to say "another vote for this answer," but it is so clearly correct that it's not like voting for it means anything.

Anyway, yes there is a difference and this is it.