THE EXISTENTIAL IMPORT OF PROPOSITIONS. 543 predicates existence serve as the copula, it does not seem certain that we can advance from this to a full existential implication in the copula (though the question whether we can is worth a careful investigation) ; and it is therefore a simpler and more satisfactory course to inquire what we can infer as to the existence of the subject from the mere fact of an affirmation as such. On this point it is pleasant to be able to express a strong opinion that Mill has indicated the true doctrine, 1 and that it is only by a retrograde movement that a settlement of the question is attempted on any other basis. Mill's doctrine already referred to is that an accidental (i.e. real) affirmation implies "the real existence of the subject, because in the case of a non-existent subject there is nothing for the pro- position to assert". Of this, Dr. Keynes says 2 that it is "no doubt the view that, at any rate on a first consideration of the subject, appears to be at once the most reasonable and the most simple ". Some of us are constrained to go much further, and to say that it appears to be a plain and necessary truth. No doubt it requires to be guarded. " Beal " existence must be understood in reference to whatever universe of discourse is in question. Mih 1 overlooked this, and committed himself to the very questionable statement that " such a proposition as, The ghost of a murdered person haunts the couch of his murderer, can only have a meaning if understood as implying a belief in ghosts ". But surely such a statement might naturally be made by the most thorough disbeliever in ghosts, if his discourse re- lated to the universe of mythology. Take, however, a statement much more likely to occur. If I say, The Olympian gods prac- tised many shameful deeds, the proposition is real and not un- meaning. Mill does not provide for such a case, but at the present time it presents no difficulty, and there is probably no fear of controversy arising with regard to it. But if Mill's statement is modified in the light of the essential doctrine of varying universes of discourse, I believe that nothing more is required. The statement is then not only true, but with- in the truth ; for it holds good for verbal as well as for real pro- positions. Mill was compelled to exclude verbal propositions, because definitions could be given of imaginary things. But to us this is no difficulty, and it is surely as impossible to give a definition of the non-existent as it is to make any affirmation about it. But Mill's doctrine, however simple and cogent, has not com- manded universal assent; and Dr. Keynes has recently main- tained that many propositions are of a character altogether in- consistent with the doctrine. 3 He has adduced several plausible examples ; but I believe that it is possible to show that they are only apparent exceptions. Dr. Keynes' own view is that categorical propositions of what- 1 Loc. tit. 2 Formal Logic (3rd ed.), 117. 3 Op tit., pt. ii., c. 7 passim, especially 122, 123.
