Books on Amazon
Logical possible/possibility/diamond/KripkeVsField: "it is possible that" is not a logical truth. - FieldVsKripke: yes it is, this is due to Kripke's model-theoretical definition. - It should not be read "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 logical. - ((s) Even without meaning postulates. ((s) Meaning postulate/(s): this is about the extent of the logic.)
Logical possible/FieldVsKripke: "It is possible that there is an electron": is true in all models, therefore logically true. (> Logical possibility is itself logically true)._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
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