John R. Welch

This chapter examines gruesome predicates, the most notorious of which is 'grue'. It proceeds by extending the analysis of Theo A. F. Kuipers' From Instrumentalism to Constructive Realism in three directions. It proposes an amplified typology of grue problems, first of all, and argues that one such problem is the root of the rest. Second, it suggests a solution to this root problem influenced by Kuipers' Bayesian solution to a related problem. Finally, it expands the class of gruesome predicates by incorporating Quine's 'undetached rabbit part', 'rabbit stage', and the like, and shows how they can be managed along the same Bayesian lines.