Unless/Except Perhaps = Until/Without?

[ldanny24]

Hello,

I just went over your conditional lab and found the handy trick of Unless/Except Perhaps to be replaced with "If not" very useful. My question though is if this same trick can be applied with the words Until and Without. So like,

1.) There is no peace unless we have justice

2.) There is no peace without justice

In the first one by using the "If not" trick we can say: If there is no justice then we have no peace, which also means If we have peace then we have justice. In the second one it seems the "without" can mean exactly the same thing: If there is no justice then we have no peace.

The same thing can be said for Until

3. There is no peace until there is justice

Also known as, If there is no justice (the intruder) then we cannot have peace.

I'm not sure if i'm generalizing this too much or if there are certain nuances I'm not seeing. I think if we can use the trick of replacing If not with Unless/Except Perhaps/Without/ and Until that'll become a huge time saver on the test. Thanks in advance.

[noah]

Great realization! (And correct). What you've done is hit upon the fact that those words all indicate what is necessary in the relationship. And, if you don't have something that is necessary, you can't have the sufficient.

Again, nice work.

[charles.dj.kim]

This is regarding preptest 24 Game 4 for the last rule.

Rule: V cannot be prescribed unless both H and M are prescribed.

Based on the "if not" rule.. doesn't this mean:

If not H & M --> not V

with contrapositive

V --> H or M



It seems that in order to answer the questions, it has to be:

If not H OR M --> not V
If V --> H & M (contrapositive)

Please help!