Abstract
This paper considers the connections between semantic shiftiness (plasticity), epistemic safety and an epistemic theory of vagueness as presented and defended by Williamson (1996a, b, 1997a, b). Williamson explains ignorance of the precise intension of vague words as rooted in insensitivity to semantic shifts: one’s inability to detect small shifts in intension for a vague word results in a lack of knowledge of the word’s intension. Williamson’s explanation, however, falls short of accounting for ignorance of intension.