I accept a dispositional account of belief. That is, I think of believing as being disposed to act and cogitate and feel in certain ways under certain conditions. An alternative approach holds that to believe is to have some sentence-like representation stored in one's mind. (See my forthcoming Stanford Encyclopedia entry on belief and my Phenomenal, Dispositional Account of Belief for more on this.)
One point of contrast between these two approaches: On a representational warehouse approach to belief, it seems perfectly natural to suppose that sometimes we have baldly contractory beliefs. One might believe both P and not-P simultaneously; one might believe, say, both that God exists and God doesn't exist, or that lighting the match is safe and that lighting the match is not safe. All that's required is that one has the sentences or representations of both P and not-P stored (in the right way) in one's mind.
Dispositional approaches generally don't countenance baldly contradictory beliefs. The dispositions to act in accord with one belief will tend to flatly contradict the dispositions to act in accord with its negation. One can't, for example, simultaneously be disposed both consistently to act as though God exists and consistently to act as though he does not exist. At most, one will have a muddled, mixed-up, in-betweenish set of dispositions, such that it's not quite right to say that you believe that P and not quite right to say you don't.
Is it ever compelling to suppose that a person genuinely has simultaneous and baldly contradictory beliefs?
Consider the self-deceived person who sometimes and in some respects acts as though she perfectly well knows that her son is a drug dealer and who at other times and in other respects perfectly sincerely denies that he is. We might say part of her believes it and part of her doesn't -- but that's merely metaphorical. She doesn't literally have different compartments in her mind, with divergent judgments, alternating control over her behavior, does she? Surely it's at least as plausible to say that she's in a confused state somewhere between believing it and failing to do so -- perhaps somewhat like H.H. Price's "half belief" (compare the case of Geraldine in my Phenomenal, Dispositional Account of Belief).
Or take the man who lights the match to see in the dark, momentarily disregarding the fact that there's a gas leak -- an example sometimes cited by philosophers as a case of baldly contradictory belief. Is it really compelling to say that he both believes that lighting the match is safe and that it isn't?
Can you think of a better case? (If the "paradox of the preface" comes to mind, I'll deal with that in a future post.)