According to the traditional view, a mental state is luminous in that if one is in a mental state, then one knows, or at least is in a position to know, that one is in that mental state. Phenomenal mental states, such as pain and feeling cold, are cou...
According to the traditional view, a mental state is luminous in that if one is in a mental state, then one knows, or at least is in a position to know, that one is in that mental state. Phenomenal mental states, such as pain and feeling cold, are counted as representative instances of luminosity.
However, Timothy Williamson invented an ingenious argument against the traditional view. It is called ‘Anti-luminosity Argument.’ According to the argument, the luminosity of phenomenal mental states is inconsistent with the thesis that if one knows that p, then in a very similar situation, p should hold. Because the thesis, which he calls ‘margin for error principle,’ can be derived from plausible assumptions about knowledge and human capacity, Williamson rejects that phenomenal mental states are luminous. But recently Selim Berker contended that Williamson's argument is not successful for two reasons: firstly his argument in effect relies on a soritical premise and secondly it implicitly assumes that there is no constitutive connection between phenomenal mental states and cognitive states.
In this essay I defend the Anti-luminosity Argument by making two responses to Berker's challenge. Firstly I clarify the form of the premise that Berker doubt to be soritical and show that the premise is soritical only when a certain condition is satisfied at every step of Anti-luminosity Argument. I concede that Berker's criticism is correct as to Williamson's original argument but argue that it is possible to revise the original argument not to satisfy the condition, so that the premise is not soritical. Secondly I suggest a way of understanding the relation between phenomenal mental states and related doxastic states. My suggestion is to view the relation not as ontological but as conceptual within the framework of folk psychology. And I argue that the core idea of the Anti-luminosity Argument can be retained on this view.