is always true' is to mean 'it is false that not-
is sometimes true.'"[39] But for reasons connected with the theory of types it seems more correct to take both "always" and "sometimes" as primitive ideas, and define by their means the negation of propositions in which they occur. That is to say, assuming that we have already defined (or adopted as a primitive idea) the negation of propositions of the type to which
belongs, we define: "The negation of '
always' is 'not-
sometimes'; and the negation of '