Since Hume, philosophers of induction have debated the question of whether we have any reason for assuming that nature is uniform. This debate has always presumed that the uniformity hypothesis is itself coherent. Part I of this essay argues that a proper appreciation of Goodman's grue-green problem should lead us to the conclusion that the uniformity thesis, under its usual interpretation as a strictly ontological thesis is incoherent. Part 2 argues that further consideration of the grue-green problem leads to the conclusion that certain popular versions of the thesis of physical supervenience/primacy of physics are incoherent. Part 3 argues that the notions of natural kinds and nature's joints should not be taken as ontologically objectiv...