Principle: If one does not criticize a form of behavior in oneself or vow to stop it, then one should not criticize that form of behavior in another.
Principle
not criticizing yourself for behavior X shouldn't criticize and → someone else not vowing to stop X for doing X
Application
Shimada doesn't vow to → shouldn't criticize stop being tardy himself M for tardiness
Evaluate
Principle-Application questions are dreamy, because they are very self-similar.
1. We're given a rule 2. The application is trying to conclude the right side of the rule 3. Something about the left side of the rule still hasn't been clearly established, and that's our whole job -- figuring out what that is.
This application is indeed concluding the right side of the rule, shouldn't criticize someone else for [tardiness].
Have we established that "Shimada doesn't criticize himself for being tardy" and that
Not quite. We only established that Shimada hasn't vowed to stop being tardy himself.
Why do we need both? Isn't the rule saying or?
It does seem that way at first, but if it were really an or trigger, then saying that Shimada doesn't vow to stop being tardy himself would be sufficient to trigger the rule. If the application were already a correct usage of the rule, then there would be no room for them to ask us a Strengthen question. You can't strengthen something that's already valid.
So part of how we'd figure out that the trigger is and, not or, is just by understanding that something has to be missing currently.
When you say that something is not X or Y, you're saying ~ (X or Y)
This is almost like distributing a -1 in algebra. ~ (X or Y) = ~X and ~Y
Think of a more conversational example: If you are not vaccinated or recovered from covid, then you should wear your mask.
When we say "X or Y → Z", we could re-write that as X → Z and Y → Z
When we see,
If you are not vaccinated or recovered from covid, then you should wear your mask. if we treated it the same way as the above, we'd get not vaccinated → should wear mask recovered from covid → should wear mask
That second one doesn't make any sense. If you've had covid and recovered, then you should wear a mask? That's not what we meant. We were saying if you haven't already had and recovered from covid, then you should wear a mask.
This trigger, If you are not vaccinated or recovered from covid is really meaning "If you are not vaccinated or (not) recovered"
But the "not" isn't written again there because it's modifying the "vaccinated or recovered". The trigger is saying,
To not belong to that crew means that you have not been vaccinated and have not already recovered from covid.
The tl;dr version of that is, when we say "if you're not X or Y", we're saying, . So we're saying, .
Goal
We have half the trigger (hasn't vowed to stop being tardy), but we need the other half of the trigger (doesn't criticize himself for his tardiness).