Books on Amazon
Logically possible/possibility/diamond/KripkeVsField: "it is possible that" is not a logical truth - FieldVsKripke: that is only due to Kripke's model-theoretical definition. - It should not be seen as "mathematically" or "metaphysically possible".
E.g. Carnap: "He is a bachelor and married": is logically wrong - (> meaning postulates) - FieldVsCarnap: Meaning relations between predicates should not belong to logic. - Then the sentence is logically consistent. Consistency operator/Field: MEx (x is red & x is round) - should not only be true, but logically true. - ((s) Even without meaning postulates - (meaning postulate/(s): this is about the scope of logic.)
Realism, Mathematics and Modality Oxford New York 1989
Truth and the Absence of Fact Oxford New York 2001
Science without numbers Princeton New Jersey 1980