Again a short look at Aristotle's resolution (one of many) of the sea battle paradox:
In one famous example about a hypothetical sea battle, [Aristotle] observes that the necessary truth of a mere proposition does not trump the uncertainty of future events. Because it is necessarily true that there will be or will not be a sea battle tomorrow, we cannot conclude that either alternative is necessarily true. […] So the necessity that attaches to the proposition “there will or will not be a sea battle tomorrow” does not transfer over to the claim ‘that there will be a sea battle tomorrow” or to the claim “there will not be a sea battle tomorrow.”
The sea battle argument is based on the theorem (P ∨ ¬P) in propositional logic. In itself this theorem doesn't seem to give us anything absurd under the interpretation that P could stand for “there will be a sea battle tomorrow” – exactly for the reasons described above.
But the soundness criterion for propositional logic is about truth assignments: any truth assignment to propositional variables in a theorem will reduce to “true”. But doesn't this at least hint at the assumption that any propositional variable has either truth value “true” or “false” – which again gives rise to the sea battle paradox?