B. Variations on the Deontology

The above involved extensions of the classical foundationalist ingredient of the classical picture. Note that we can also ring the analogical changes on the deontological component, and we can mix and match the extensions in a dazzling variety of combinations. I can’t possibly examine all these multifarious versions of evidentialism in all their 104permutations and combinations,¹¹⁵¹¹⁵   For some of them, see WCD, chapter 1. I leave as homework the problem of showing that Christian belief can indeed be justified on these construals. but I do wish to examine one particularly salient variety: Alston justification, which is believing on the basis of a reliable ground or indicator. Alston puts it as follows:

to be justified in believing that p is to be in a strong position for realizing the epistemic aim of getting the truth. . . . I will begin by making the plausible assumption that to be in an epistemically strong position in believing that p is to have an adequate ground or basis for believing that p. Where the justification is mediate, this ground will consist in other things one knows or justifiably believes. Where it is immediate, it will consist typically of some experience. . . .¹¹⁶¹¹⁶   Perceiving God (Ithaca: Cornell University Press, 1991), p. 73.

A belief is justified, therefore, if and only if it is formed on the basis of an adequate ground. Clearly, Alston justification differs radically from the original deontological notion. That is because it doesn’t contain so much as a hint of the deontology of the classical picture: “I reject all versions of a deontological concept [of justification] on the grounds that they either make unrealistic assumptions of the voluntary control of belief or they radically fail to provide what we expect of a concept of justification.”¹¹⁷¹¹⁷   Ibid. Well then, why does he call what he proposes ‘justification’? Or better, why do I consider it under the rubric ‘justification’? How is it an analogical extension of that notion? The answer is that what it requires—that the belief in question be based on a truth-conducive ground—is an analogical extension of what, according to the classical picture, is the relevant duty. There is a complex and interesting relation between justification taken deontologically, as in the classical picture, and Alston justification (justification as truth-conducive evidence or ground). The latter discards the deontology of the former, but takes the term ‘justification’ to denote the condition which, according to the former, is sufficient for satisfying the duty that, according to the former but not the latter, is in fact laid on us human beings. (I’ll leave as homework the problem of figuring out how to state this more intelligibly.)

Now what sort of animal is a ground of belief? A mediate ground of a belief, according to Alston, is another belief, on the basis of which the belief in question is formed; an immediate ground of a belief is an experience, on the basis of which the belief is formed. And what is it for the ground of a belief to be adequate? “The ground of a belief will suffice to justify it only if it is sufficiently indicative of the truth of the belief. If the ground is to be adequate to the task, it must be the case that the belief is very probably true, given that it was formed on that basis.”¹¹⁸¹¹⁸   Ibid., p. 75. The idea, therefore, is that the ground G of a belief B is adequate 105just if a certain conditional probability is high: the probability that B is true given that it has been formed on G. And here the probability in question is an objective probability¹¹⁹¹¹⁹   See WPF, pp. 138ff. of some sort; if a belief B is justified, then it was formed on the basis of a ground G, such that the objective conditional probability of B on G (P(B/G)) is high. I form the belief that the largest oak in my backyard is now losing its leaves. I form this belief on the basis of experience of some kind—as Alston might state the matter, it seems to me that the tree is presenting itself to me as losing its leaves. Then that belief is justified if and only if it is objectively probable that the tree is losing its leaves, given that I undergo that experience. Putting these elements together, we can say that a belief B is justified—actually, prima facie justified—for S if and only if it is formed on the basis of a truth-conducive ground G—if and only if, that is, it is formed on the basis of some ground G, such that the objective probability that B is true, given that it has been formed on G, is high.