The epistemic duty to seek more evidence.

... though we cannot hinder our knowledge where the agreement is once perceived, nor our assent, where the probability manifestly appears upon due consideration of all the measures of it; yet we can hinder both knowledge and assent, by stopping our inquiry, and not employing our faculties in the search of any truth. If it were not so, ignorance, error, or infidelity, could not in any case be a fault.

Locke, Essay; Bk IV, xx, 16

From Eve on down the generations nearly everyone has held there are epistemic goals worth some risk or effort to pursue. Following James' admonition to know the truth and avoid error, many recent epistemologists have formulated the overall epistemic goal as being to believe all and only true propositions [Alston, 1988, p. 258; Steup, 1988, p. 74; Feldman, 1988, p. 247; Foley, 1987, p. 8, fn 3]. Although one might have qualms about this goal, especially the "all" part (is it really our epistemic goal to believe completely unimportant, useless truths?), we shall adopt it for the purpose of this paper. Indeed, we believe it is correct. But our purpose isn't to argue for it. Rather it is to show that if you accept this goal, you are committed to a certain arduous consequence. Many will take this consequence as constituting a reductio of the goal. But if, like us, you accept the goal, the implication is rather that we must gird up our epistemic loins. Life after Eden is epistemic travail.

I. EPISTEMIC DUTIES

If you accept a goal G, and action A is the best way of achieving G, then there is a sense in which you ought to do A or in which it would be rational for you to do A. We shall say that A is a duty relative to G, although we don't intend any moral overtones in this use of the word `duty'. So where there are goals, there are correlative duties. A distinction must be made, however, between what we will call objective and subjective correlative duties.(2) The objective duty correlated with goal G is the action that will in fact best lead to G. The subjective duty is the action that the agent believes will best lead to G, or rather the action that the agent believes will best lead to G when she has tried her best (or at least tried adequately) to determine which action will best lead to G. Consider a moral instantiation of this distinction, say in a Utilitarian setting. The goal is to maximize happiness. If the action that will in fact maximize happiness is A, then the agent's objective duty is to do A, whether she knows it or not. But if when she tries her best to do the utilitarian calculation she comes up with action B, then that's her subjective duty. She can't be blamed for not doing A but only for not doing B.

Applying all this to epistemology, we can say that where there are epistemic goals, there are correlative epistemic duties, objective and subjective. We are taking the epistemic goal to be believing all and only truths. For any true proposition p, the action which will in fact best lead to this goal is simply believing p. So for any true proposition p, one's objective epistemic duty is to believe p. Similarly, for any false proposition, one's objective epistemic duty is to not believe it. End of story about objective epistemic duties.

More interesting is the question of subjective epistemic duties. Abbreviating our earlier formulation ("the action that the agent believes will best lead to G when she has tried her best to determine which action will best lead to G") and applying it to the epistemic case, we get Chisholm's famous description of a person's duty as "trying his best to bring it about that, for every proposition h that he considers, he accepts h if and only if h is true." [Chisholm, 1977, p. 14](3,4) But this doesn't give us much guidance. What exactly should one do in trying his best to believe h iff h is true?

Those of us in the Western rationalistic tradition will agree that doing one's best to believe truly involves considering the evidence. Evidence is our best guide to truth; the more the evidence supports a proposition, the more likely it is the proposition is true.(5)

A variety of specific rules have been proposed for how our beliefs should be related to our evidence. They range from stringent Cartesian versions requiring certainty for belief, to more lenient (and more plausible) versions enjoining belief, disbelief, and withholding, respectively, for positive, negative, and neutral evidence. Since these alternative rules state how an agent's present belief should be related to her present evidence, we will refer to them as versions of our subjective "synchronic" epistemic duty [see Foley, 1988, p. 127]. (Hereafter, for brevity, we often omit the qualifications "subjective" and"epistemic" in discussing these duties.)

Is our only duty, relative to the epistemic goal of believing all and only truths, the synchronic duty of appropriately adjusting our present beliefs to our present evidence? Do we not have "diachronic" duties that look to the future--duties to seek new knowledge, to investigate unexplored fields, to go where no one has gone before? More mundanely, do we not at least have a prima facie diachronic epistemic duty to seek further evidence concerning propositions about which we are uncertain?

Several recent epistemologists seem to deny there is any such epistemic duty [Foley, 1993, p. 19; Feldman, 1988, p. 250-252]. They argue that the synchronic duty is the only strictly epistemic duty. `... the key question related to epistemic obligation is "what should I believe now?." ... ' [Feldman, 250] Apparently they hold this view about epistemic duties because they take the epistemic goal of believing all and only truths to be a "present tense" goal: to …