Propositional and Doxastic Justification: Their Relationship and a Questionable Supervenience Claim

Propositional justification pertains to propositions: it is the sort of justification that a proposition enjoys for an agent when the agent is epistemically justified to believe it. By contrast, doxastic justification is justification of beliefs, i.e., of doxastic states actually instantiated by an agent. The ‘orthodox’ view of the relationship between propositional and doxastic justification is that the latter should be explained in terms of the former, so that an agent’s belief is (doxastically) justified just in case (i) it is a belief in a proposition that is (propositionally) justified for the agent and (ii) it is held on the basis of that which (propositionally) justifies its content. This view has been challenged by John Turri in his paper ‘On the Relationship between Propositional and Doxastic Justification’ (Philosophy and Phenomenological Research, 80, 2010, pp. 312-326). There he offers two putative counterexamples to the orthodoxy and goes on to argue that the order of explanation should be reversed: it is propositional justification that should be explained in terms of doxastic justification, and not vice versa. Though I share Turri’s feeling that there is something amiss with the way a number of contemporary epistemologists talk of propositional and doxastic justification, I do not believe he has managed to put his finger on the real trouble. So the first point I make is that his counterexamples fall short of refuting the orthodox view, which I argue should be maintained. Then I try to diagnose the real source of the trouble. It lies, I suggest, in the way a number of recent epistemologists talk of propositional justification, a way which commits them to the questionable view that the basis upon which facts concerning propositional justification supervene does not include facts concerning the doxastic states of agents, but only facts concerning the evidence to which agents have access. So I observe that there are different degrees of idealisation involved in judgments of ‘propositional justification’, propose to distinguish what an agent is propositionally justified to believe given her overall doxastic state from what an agent is propositionally justified to believe irrespective of her overall doxastic state, and argue that, whenever it is the former relation that is at stake, an agent can be propositionally justified to believe a proposition p at time t only if it is reasonably easy for her to form a doxastically justified belief in p at t. It is most likely an awareness of this fact, or of some fact in the vicinity, that encourages the belief that propositional justification should be explained in terms of doxastic justification. But I suggest that this fact, far from being evidence that the notion of doxastic justification is in any sense more fundamental than that of propositional justification, can be accounted for by paying at¬tention to the relationship that links the relevant sort of (epistemic) justification to (epistemic) responsibility. So I conclude that there is an important sense in which facts concerning epistemic justification supervene not merely on facts concerning the evidential states of agents, but on facts concerning their overall doxastic states.