Purism and conservatism: response to Nolfi

In this response to Kate Nolfi's comments on On Folk Epistemology, I defend the book's arguments in favor of strict purist invariantism and against pragmatic encroachment. I first defend the negative Argument Argument against pragmatic encroachment by arguing that Nolfi's ingenious cases do not compromise it or my heuristic proxy/directive force account of practical factor effects. Second, I consider Nolfi's suggestion to amend the book's three methodological principles with a fourth Principle of Vindication and argue that while there is a grain of truth to it, it grants too much epistemic force to intuitive judgments about complex cases.