There are positive & negative facts: if the proposition “this rose is not red” is true, then what it signifies is negative. But the occurrence of the word “not” does not indicate this unless we know that the signification of the proposition “this rose is red” (when it is true) is positive. It is only from both, the negation & the negated proposition, that we can conclude to a characteristic of the significance of the whole proposition. (We are not here speaking of negations of general propositions, i.e. of such as contain apparent variables. Negative facts only justify the negations of simple || atomic propositions.)