|Geach, Peter T.
Books on Amazon
Command/Moral/Logic/Geach: a statement-line cannot be in an if-clause. - "If you want ..." these are real imperatives, only grammatically a hypothetical sentence. - The wish itself has nothing to do with the truth conditions. - But an utterance does not get empty qua imperative, simply because it cannot be fulfilled.
Imperative/Logic/Geach: difficult problems: "Tu x or tu y!" Cannot be interpreted as "I command x or I command y" - analog to assertions: l- p v q cannot be interpreted as l-p or l-q.
Solution/Hare/Geach: distinction neustic/tropic/Hare (> Hare, R.M.) - E.g. tropic: is identical in "Tu x or tu y" and "You will do x or you will do y". - Phrasticon: "Your future doing of either x or y" - Neusticon: "Please!" or yes". (assertorically).
Disjunction/Geeach: it belongs to the tropic. - Neustic: is added to the tropic as a whole, not to one or the other disjoint.
Zoglauer I 23
Definition Tropic/Hare: descriptive component of a standard sentence-
Definition Neustic/Hare: prescriptive component of a standard sentence.
Logic Matters Oxford 1972
Einführung in die formale Logik für Philosophen Göttingen 2002