  These questions and the argument leading to them are very reminiscent of Goodman's treatment of induction (Goodman 1954). Goodman's  “new riddle of induction”,  commonly called the grue paradox, invites us to consider the predicate grue, which is true before time t only of objects that are green and after time t only of objects that are blue. The puzzle is that every instance of a green emerald examined before time t is also an instance of a grue emerald. So, the inductive inference that all emeralds are grue seems to be no less legitimate than the inductive inference that all emeralds are green. The problem, of course, is the choice of predicates. Goodman showed that inductive inference only works in the context of the right set of predicates, and Fodor demonstrates much the same point for the common sense law of inertia.