Talk:Formal Logic/Predicate Logic/The Predicate Language

Sentential connectives, undefined d
Regarding the line "F(f(d)) V G(g(7,3),1,4) is true": d is not defined — or am I missing something? Since G(g(7,3),1,4) is false (7 is not between 1 and 4) F(f(d)) must be true (The father of d is bald). Maybe we should introduce a well-known Mr. or Ms. d with a well-known, rather bald father. Like d = Luke Skywalker and f(d) = Darth Vader, but those two belong to fiction and are not a good example. W.D. Sparling (discuss • contribs) 18:22, 15 December 2017 (UTC)