Are We Luminous?

Abstract

Since its appearance over a decade ago, Timothy Williamson's anti‐luminosity argument has come under sustained attack. Defenders of the luminous overwhelmingly object to the argument's use of a certain margin‐for‐error premise. Williamson himself claims that the premise follows easily from a safety condition on knowledge together with his description of the thought experiment. But luminists argue that this is not so: the margin‐for‐error premise either requires an implausible interpretation of the safety requirement on knowledge, or it requires other equally implausible (and soritical) assumptions. In this paper I bolster the margin‐for‐error premise against these attacks by recasting Williamson's own two‐part defence, the first part intended to work on the assumption that there is no constitutive connection between the phenomenal and the doxastic, and the second intended to work without this assumption. Pace various luminists, I argue that the appeals to safety needed for Williamson's two‐part defence (the first in terms of outright belief, the second in terms of degrees of confidence) are plausible. I also argue that all that is needed to generate the margin‐for‐error premise from these safety conditions is an empirical assumption about the kinds of creatures we are: that is, creatures whose beliefs are structured by certain dispositions. By recasting the anti‐luminosity argument in this way, we can understand what is really at stake in the debate about luminosity: that is, whether we are luminous.