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I understand that when folks say "modal logic" in this context, they're generally referring to model logics that implicitly quantify over poorly-defined spaces. However, that's not what all modal logics are like...
Consider my eyes opened.
Equivalently: you can use whatever logical operators you like, if you can define the operator's meaning without reference to the operator.
This is my problem with the modal logics I have encountered - bad or unclear definitions of the modal operators.