"Unless" in Loophole vs. Group 3 in 7Sage

PurplePep23

I'm going through the Loophole in Logical Reasoning book now and there are several pages dedicated to the indicator "unless." Loophole specifies that you must make the target of "unless" the necessary condition, and the sufficient condition is "the way things always are." But 7Sage loops "unless" in (with what Loophole would call "either/or") with Group 3 and says you just have to choose either half of the conditional, make it the sufficient condition, and negate it.

Does the extra distinction in Loophole matter? i.e. is 7sage too broad on "unless"?

FaviPapi-1-1

It seems like you are trying to find "shortcuts." If that is the case, then you shouldn't since the LSAT is not a standard exam in its particular content so to speak. You should learn the ins and outs of a rule such as when the word "unless" is used in a statement.

That said, I don't even remember what the "Group 3" was all about... Do I need to know? No. Did I study and learn from it ? Yea and it's all in my head...

Here is example of how to go about the word "unless":

"Tom cannot go to the park unless he goes to the gym"

1. If Tom goes to the park then he goes to the gym

2. If Tom doesn't go to the gym, he doesn't go to the park.

1 and 2 are equivalent; one is the contrapositive of the other and vice-versa.

I hope this helps.

JPJ July2021

I'm familiar with what you're talking about and I think it's just two different ways of expressing the same idea. Use what works for you.

canihazJD

I agree with @FaviPapi just learn the actual concept. On harder questions, the test will punish you for reliance on shortcuts. I found it better to do it that way, then you can see how those rules like "negate, sufficient" or "if not" work and can be interchanged.

PurplePep23

@FaviPapi @canihazJD I am not trying to find a shortcut, I am trying to figure out which of the two explanations is correct because it seems like they are at odds with each other. Loophole says that the necessary condition must be the target of "unless," but 7sage says that that specificity is not needed, i.e. that either part of the conditional can be necessary as long as the sufficient is negated.
So my question is - which is correct? If Loophole is correct, then I could be placing the "wrong" part of the conditional as the necessary condition when looking at an "unless" statement.
Let me know if that makes more sense.

Jordan Johnson

@PurplePep23 I've used 7sage and the Loophole and they both should yield the same result.

For example, if you're given:
~A unless B.

Loophole Method:
1. Keep B in necessary.
2. Negate the sufficient condition.

Result:
A --> B

7Sage Method ("Group 3"):
1. "Negate, sufficient."

Result:
A --> B

I think you're getting confused because you could also use 7Sage's Method this way:

1. Choose to use B as the sufficient.
2. Negate it.

Result:
~B --> ~A

... which is just the contrapositive of A --> B

Hope that helps!

hopefulling

I treat 'unless' like the Loophole, and have it mentally grouped in as: 'unless, until, except, without' ... 'or.' It was the way I had first memorized it (from Powerscore and then Loophole) and it's the fastest way for me to process it. When I read it connected to 'either/or' in the 7sage curriculum, I didn't re-classify it, I prefer the way Loophole explains it. I've also seen it grouped in with those other indicators (until, except, without) in a couple of logic textbooks.

I agree with one of the posts above, to just pick the method that you like best. I did find the discrepancy odd, but I know that some sources have these discrepancies and we just have to process them on a case-by-case; that there must be two ways of considering it.

PurplePep23

Thanks @"Jordan Johnson" @hopefulling ! Very helpful and that clears it up for me.

Sailor Moon LSAT

I found the loophole explanation to be confusing. I like 7sages better tbh for unless.

Burden.of.Floof

I just finished that section and I know exactly what you're talking about! I think JY's way is a good fail safe. Like, if you get panicky on a question, it's good to know that all you have to do is negate the sufficient. I found her mechanical translation to be a bit clunky for me personally, but it comes down to what works the best for you.

What I really appreciated about her explanation was the last page or so where she explains where people mess up when translating unless and why intuitively, that's wrong. I know for me, that's what I found the most valuable in the Loophole re: unless.

This_is_Hard

@"Jordan Johnson" well done, instead of dancing around the OPs question, you answered it succinctly. Shows true mastery.