In this essay I argue that the anti-luminosity argument Timothy Williamson presents in Knowledge and Action runs into problems in trying to establish its conclusion. Anti-luminosity is the position that we sometimes do not know our current mental states, for example I can feel cold and not know that I do. Williamson’s argument initially seems plausible; however, it relies on an inadequately supported premise. Williamson needs to assume that the process by which we come to know our current inner states is fallible, but in doing so begs the question. Without assuming a fallible inner sense, the anti- luminosity argument looks like just another sorites paradox. Without problematically assuming fallible introspectors the anti-luminosity argument cannot establish its conclusion. One may think that this assumption is justified, but I argue that it is not. There are at least two other positions on the table that avoid a problem Williamson’s position must face
