Earman on the Projectibility of Grue

Abstract

In Bayes or Bust?, John Earman attempts to express in Bayesian terms a sense of "projectibility" in which it is logically impossible for "All emeralds are green" and "All emeralds are grue" simultaneously to be projectible. I argue that Earman overlooks an important sense in which these two hypotheses cannot both be projectible. This sense is important because it allows projectibility to be connected to lawlikeness, as Goodman intended. Whether this connection suggests a way to resolve Goodman's famous riddle remains unsettled, awaiting an account of lawlikeness. I explore one line of thought that might prove illuminating.