By DOUG SHAVER
November 2009
The current debate over the problem of evil is well epitomized by arguments presented by Paul Draper and Peter van Inwagen. Draper (1989), implicitly conceding that there is no formal contradiction between the existence of evil and the existence of a benevolent god, argues that there remains an evidential case to be made for the inference that the coexistence of evil and of divine benevolence is not rationally credible. Van Inwagen (1991) offers a counterargument that such an inference is unjustified. In this paper I will compare their arguments and defend my judgment that, although van Inwagen successfully undermines Draper's particular case in one sense, the general case against theism remains unaffected in another sense.
Draper presents an evidential argument from evil intended to demonstrate the irrationality of the form of theism that has been historically dominant in the Western world during most of the present era. He defines theism as the statement that "There exists an omnipotent, omniscient, and morally perfect person who created the universe" (331). He offers as the alternative hypothesis a generic assertion that makes no existential commitments but affirms only that whatever caused our existence was unconcerned about our comfort or welfare. Draper formulates it as the Hypothesis of Indifference (HI): "Neither the nature nor the condition of sentient beings on earth is the result of benevolent or malevolent actions performed by non-human persons" (332). He weighs these hypotheses, theism and HI, against a set of observations O comprising "both the observations one has made of humans and animals experiencing pain or pleasure and the testimony one has encountered concerning the observations others have made of sentient beings experiencing pain or pleasure" (332). He argues that O has a much greater antecedent probability on HI than on theism. This, he says, establishes a prima facie case for regarding HI as much more probably true than theism.
His argument for the high probability of O on HI appeals to the biological utility of pain and pleasure, which are effective means of getting organisms to avoid behaviors inconsistent with their goals and to persevere in behaviors consistent with their goals (334-35). But we also observe ourselves and other creatures experience pain and pleasure that has no apparent biological utility (335). Draper also notes that pain and pleasure "have intrinsic moral value," and this leads us to expect certain things about its distribution among sentient creatures that (like humans, for instance) also happen to be moral agents (336). Such expectations, he argues, lead us to think the observed distribution to be consistent with HI but very surprising on theism (339). For anyone who can see all this, Draper says, it is irrational to continue holding a belief in God unless they can come up with a credible theodicy (334). Draper says no one has produced a credible theodicy yet and it seems unlikely that any will soon be forthcoming (346).
Van Inwagen's counterargument is not a direct response to Draper but makes enough relevant points to be effective against it. Van Inwagen addresses a version of the evidential argument that he says "owes a great deal" to Draper's but is not intended to be "even a simplified version of it" (161). He denies that the argument succeeds in demonstrating the irrationality of theism because, he says, theism is in fact defensible notwithstanding the alleged shortcomings of any current theodicies. The believer, according to van Inwagen, does not even need a theodicy. To be rational, he says, theism needs only a defense, which he defines as is "a story according to which God and suffering of the sort contained in the actual world both exist, and which is such that (given the existence of God) there is no reason to think that it is false, a story that is not surprising on the hypothesis that God exists" (141). Such a defense, he says, works by undermining Draper's assertion that we know P(O/theism) -- the probability that the world as we see it is the sort that a morally perfect God would have created -- to be quite low. It makes no difference, according to van Inwagen, whether we can establish a high probability for P(O/theism) (141). What matters is that we have no grounds for assigning it any probability at all (151). We are simply ignorant on this point and, given that ignorance, we cannot justifiably impugn the rationality of theism, and in that case it follows that the evidential argument from evil fails (161).
This is his primary argument. He supplements it with two arguments by analogy. In one, he compares theism with the ancient Greek hypothesis that anticipated modern atomic theory. In the other, theism is compared with the hypothesis that extraterrestrial intelligent life exists. In the first, the analogue to HI is the "Hypothesis of Independence," the classical notion that all matter is comprised of four independent and continuous elements. In the second, HI is the "Hypothesis of Isolation," which asserts that the earth is unique in our galaxy and other nearby galaxies in having evolved any intelligent species. In each case, he shows how the argument for HI can be undercut with a defense that undermines a claim that it is epistemically much more probable than the alternative hypothesis (152-159).
Formally, van Inwagen's primary argument seems unassailable. However, he and Draper both are arguing in terms of something they call "epistemic probability" (Draper, 333; van Inwagen, 162-63). Neither of them clearly defines this concept except for Draper's contrasting it with "statistical, physical, or logical probabilities" (333). Both suggest that it is inversely correlated with surprise -- something is probable if it is not surprising and improbable if it is surprising. But as Draper observes, epistemic probabilities "can vary from person to person and from time to time, since different persons can be in different epistemic situations at the same time and the same person can be in different epistemic situations at different times" (333). We are not all, and none of us is always, surprised by the same thing. And, as van Inwagen points out, something improbable is not necessarily surprising (163). In light of this vagueness, it seems not entirely certain that Draper has proved anything that a theist needs to refute.
Even assuming that epistemic probability is an intuitively clear concept, notwithstanding the difficulties of stating it clearly, Draper could be overstating his case when he says it is "epistemically irrational" to maintain theistic belief if one has "a prima facie good reason to reject . . . theism" (334). The defensibility of that statement would of course depend on what Draper means by "irrational." Rationality sometimes seems to be, like obscenity, something we know when we see it but cannot otherwise define. That does not have to be a problem. If, for any painting we look at, we all agree either "Yes, it's obscene" or "No, it's not obscene," then we can reasonably suppose we all mean the same thing by "obscene," whatever that thing might be. But if we don't agree, then we probably don't all mean the same thing. And so it is with rationality. The apparent intractability of theism among a large number of people whose intellectual competence cannot be sensibly questioned might not count as evidence that God exists, but it cannot be irrelevant to the question of whether it is rational to believe that God exists.
Van Inwagen's argument is thus successful against the charge that theism is irrational, but the charge should not have been brought in the first place. But then we can ask whether it follows that atheism is irrational.
Van Inwagen concedes that evil is indeed a difficulty for theism and that theists should not pretend otherwise (159). But, he argues, a difficulty is not by itself a reason for rejecting a theory:
Just about any interesting theory is faced with phenomena that make the advocates of the theory a bit uncomfortable, this discomfort being signalled by the tendency to speculate about circumstances consistent with the theory that might produce the phenomena. For any theory that faces such a difficulty, there will always be available another "theory," or at least another hypothesis, that does not face that difficulty: its denial. (The denial of an interesting theory will rarely if ever itself be an interesting theory; it will be too general and non-specific.) (Van Inwagen, 160)
Quite so, but what makes any theory interesting in the first place is, among other things, how well it explains whatever facts its proponents claim that it explains. Draper's HI is not, we may concede, interesting per se, but an atheist would claim that, for every alleged fact that theism purports to explain, there is either a defensible alternative theory that explains it or a credible argument concluding that it is not a fact needing any explanation. Of course this claim needs its own argument, but that would take us beyond the scope of this assignment. If it can be defended, then any theodicy or other theistic defense of evil's existence is superfluous. To whatever extent atheism is antecedently credible, to that extent the problem of evil is nonexistent.
(This essay originated as a class assignment for a course in the philosophy of religion taught by Dr. Matthew Davidson at Cal State San Bernardino.)
References
Draper, Paul. 1989. Pain and pleasure: An evidential problem for theists. Nous 23, no. 3 (June): 331-50. http://www.jstor.org/stable/2215486.
Van Inwagen, Peter. 1991. The Problem of Evil, the Problem of Air, and the Problem of Silence. Philosophical Perspectives. Philosophy of Religion, vol. 5, 135-65. Ridgeview. http://www.jstor.org/stable/2214093.
(This essay last updated January 5, 2015.)