4.0641 One could say: The negation is related already to the logical place that the negated proposition determines/defines.
The negating proposition determines another logical place than does the proposition negated.
The negating proposition determines a logical place with help from the logical place of the negated proposition, in that it describes it as lying outside this place.
That one can again negate the negated proposition shows already that what is negated is already a proposition and not merely the preliminary to a proposition.
This seems fairly straightforward and correct. If I say “The monkey is in the tree” then I determine a logical place, a specific possibility from the world of all possibilities. To negate this, and say “The monkey is not in the tree,” is then to refer to quite another possibility. Whatever is denied must already have sense or meaning for there to be a meaningful denial [of it].