sentences:  In general, Gödel is sympathetic to the notion that a propositional function can be reduced to (identified with) the "real objects" that satisfy it, but this causes problems with respect to the theory of real numbers, and even integers (p. 134).He observes that the first edition of "PM" "abandoned" the realist (constructivistic) "attitude" with his proposal of the axiom of reducibility (p. 133).However, within the introduction to the second edition of "PM" (1927) Gödel asserts "the constructivistic attitude is resumed again" (p. 133) when Russell "dropped" of the axiom of reducibility in favour of the matrix (truth-functional) theory; Russell "stated explicitly that all primitive predicates belong to the lowest type and that the only purpose of variables (and evidently also of constants) is to make it possible to assert more complicated truth-functions of atomic propositions ...