When it comes to "unless" statements, you can think of them as exceptions to a rule that precedes them. If the exception ISN'T met, then you know the preceding rule must have followed as originally stated. And if the rule does not happen as originally stated, then the exception must have been triggered.
It is important to keep in mind that when an exception IS triggered, we actually can't logically conclude anything about the rule passing or not passing. If the exception is triggered, the rule might not come to pass, but it might still pass anyways. It is only when the exception is not triggered that we can conclude the rule follows.
For instance:
This rule will follow unless this exception comes to pass.
Rule DOESN'T follow --> exception came to pass
Exception DOESN'T come to pass --> rule follows
As a more concrete example, this one also parallels answer choice E:
Sally will go to the park unless it rains.
NO rain --> park NO park --> rain
It would be wrong to conclude "rain --> no park," which is a trap the LSAT often sets for "unless" statements. That is because if it does rain, that doesn't necessarily mean Sally doesn't go to the park. If it does rain, she might not have to go to the park anymore--but, she COULD still go anyways with an umbrella if she wanted to. "Unless" only allows us to draw conclusions about what happens when it's NOT raining, not what happens when it is raining.
Hope this helps!
Alex-HostonJune 1, 2022
Ok so I have 2 questions I'm still having trouble with your example and the problem itself.
1. For the question, how do we determine when there 2 quantifiers or 1 quantifiers and compound statement: unless and and/or statement because I was confused on which one to use. 2. The example you gave about the trap lsat of rain>no park? If the rule says for unless is to make the part that directly follows unless the nesscesary and then negate the other and make it sufficient how can it be flipped if it's already negative.... Not rain>>P Not park>>R I hope this makes sense
jakennedyJune 12, 2022
Hi @Alex-Hoston,
I recommend first establishing whether or not a compound statement is present. If you see AND or OR, or something with a similar meaning then you have a compound statement. If those words aren't present then it should be your typical sufficient and necessary statement.
When you have to negate a term due to an indicator like unless and it is already negated, you can just remove the negation.
Example:
Unless you A you cannot B
As you said, we begin by placing the A in the necessary:
? ? A
Then we put cannot B in the sufficient and negate it. Since cannot be is already negated, the B reverts to the positive form:
B ? A
Please let me know if this answers what you were asking.
