 Edwards regarded creatures’ inability to sustain themselves as “plain.” Kvanvig and McCann attempt to bolster this position by undermining several potential reasons for thinking the contrary. For example, one might think that the diachronic character of physical laws shows that physical objects have an innate ability to persist. If they did not, what would make the laws reliable predictors of objects’ behavior? Kvanvig and McCann find this thought lacking on the grounds that physical laws presuppose the continuing existence of the world. They are reliable because the presupposition is correct, but not because the objects they characterize are self-sustaining.