TOPIC 4 Doxastic Foundations: Atheism IS THEISM RATIONAL? 119 Ali Hasan Associate Professor University of Iowa DOES THE TESTIMONY OF SACRED SCRIPTURES FROM THE RELIGIONS OF THE WORLD FAVOR (MONO)THEISM OR ATHEISM? 127 Richard Carrier Professor The Secular Academy, Washington, DC This chapter centers around the question of whether theism is rational. We begin by discussing different theories of rationality, and introducing some importantly related epistemic concepts and controversies. We then consider the possible sources of rational belief in God and argue that even if these provide some positive support, the fact of religious disagreement defeats the rationality of theism. IS THEISM RATIONAL? Ali Hasan, University of Iowa Questions regarding the existence and nature of God (or divine reality) figure prominently in the philosophy of religion. Corresponding questions arise in the epistemology of religion regarding the epistemic status of beliefs about God. The two sorts of questions are certainly related, but our concern here is more directly with the latter, epistemological questions. Is belief in theism a case of knowledge? Does it at least qualify as rational or justified? I argue that it is not rational to believe in God. I am not, however, going to argue that it is rational to disbelieve in God or accept atheism. Perhaps it is, or perhaps agnosticism-withholding or suspending belief about the existence of God-is the only rational attitude to hold regarding God's existence. I will not try to settle which of these non-theistic positions is rational. The main argument is that any justification we might have for theism is defeated by evidence available to us, especially evidence of the unreliability of religious belief-forming practices. This defeats not only traditional monotheism, but any specific religious doctrine or specific belief in supernatural or divine reality. (The problem of evil might provide additional evidence against traditional monotheism, but is not discussed in this chapter.) KNOWLEDGE AND RATIONAL BELIEF Do we have knowledge of the existence of God? I can know that p only if p is true and I believe that p. If p is not true, then, while I might think I know that p, I would be wrong. And if I don't believe that p, it can't be knowledge for me, even if I could, perhaps quite easily, come to believe and know it. But true belief is not sufficient for knowledge. Intuitively, knowledge requires in addition that 119 my belief have some further positive property-that it be in some sense "justified," "rational," or "warranted" (and perhaps even this is not sufficient; see Gettier 1963). Many epistemologists focus on questions about the nature and extent of our justification or rationality rather than on the question of knowledge, because (a) assessments of rationality or justification are central to determining whether we have knowledge, and (b) even if we fail to know certain things (perhaps because it turns out that knowledge is very hard to get), it remains interesting to ask whether we are at least justified or rational in believing them. I will similarly focus on questions regarding the justification or rationality of belief in God, although if I am right that belief in God is not rational, it will follow that it also does not count as knowledge. I am not concerned here with whether it might be prudentially rational or morally rational to believe in God-roughly, whether it is rational to adopt the belief in God because this would be an effective means to my own well-being or the well-being of others or because it would likely improve my moral character or help me discharge some of my moral obligations. We are concerned with epistemic rationality, and although the distinction is difficult to make precise, for our purposes it will do to say that epistemic rationality of a belief is related in some intimate way to the truth (or probable truth) of the proposition believed, whereas prudential and moral rationality are not. THE STRUCTURE AND SOURCES OF RATIONALITY Epistemologists have defended many different views regarding the nature, structure, fundamental sources, and extent of knowledge and rational belief. We cannot discuss all these issues here, but we should briefly introduce two central debates in contemporary epistemology that will help us with the epistemology of religious belief: the foundationalist-coherentist debate and the internalist-externalist debate. Foundationalism is often motivated by reflecting on the fact that at least many of our beliefs depend on some sort of inference from other beliefs we have. How might the supporting beliefs be justified? Assuming that at least some of our beliefs are justified, there seem to be four options: 1. Every belief depends on (actual or available) inference from other beliefs, and each of those beliefs on yet other beliefs, ad infinitum. 2. Every belief depends on other beliefs for its justification, and the latter ultimately depend on the original belief, so that eventually the same belief appears as part of its own justification. 3. The regress terminates with beliefs that are not themselves justified. 4. The regress terminates with beliefs that are justified, but that do not depend on any other beliefs for their justification. Foundationalists hold that only the last of these options is viable. According to foundationalism, there are some beliefs-let's call them basic or foundationally justified beliefs-that are justified but that do not depend for their justification on any other beliefs; and any non-basic, justified beliefs ultimately depend for their justification on inferential relations to other justified beliefs, and ultimately on a "foundation" of basic beliefs. Option 1, infinitism, according to which the regress of reasons never stops, has hardly any proponents. It is doubtful that finite beings like us could have infinitely many distinct reasons for belief. But even granting that we could, infinitism KEY CONCEPTS Access Internalism Agnosticism Belief Coherence Theory Defeaters Disagreement Epistemic Rationality Epistemology Evidence Evidentialism Externalism Foundationalism Internalism Justification Knowledge Reformed Epistemology Skepticism Uncertainty Warrant Doxastic Foundations: Atheism 120 THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY has the counterintuitive consequence that any belief whatsoever could be justified simply by appeal to another belief that entails it, and another belief that entails the latter belief, and so on. Option 2 seems to be an endorsement of circular reasoning. It is surely no good to defend a belief by relying, even in part, on that belief itself! Option 3 isn't any better. One cannot justify a belief by simply relying on another belief that is unjustified; justifying beliefs would be much too easy! Foundationalism thus seems to be the best option (see Hasan and Fumerton 2016). Coherentists might claim that the above argument for foundationalism assumes a rather linear, one-directional conception of relations of epistemic dependence. According to coherentism, every belief depends for its justification on how well it "coheres" with the rest of one's beliefs, where coherence is determined by the web of logical, probabilistic, or explanatory relations between one's beliefs. The foundationalist-coherentist controversy remains. Many foundationalists complain that mere coherence of our beliefs does not seem to give us any reason to think that they are likely to be true and that coherentism fails to do justice to the role of experience in justification. Many coherentists worry that the foundationalist accounts of basic belief fail to make sense of how such beliefs could be justified without depending on other (doxastic) reasons. Insofar as the regress argument assumes that at least some beliefs are justified, it may be best to take the argument to be that if any beliefs are justified, then they must either be basic or ultimately depend for their justification on inferential relations to basic beliefs-not as an argument for the claim that there are any basic beliefs. Foundationalists sometimes defend the existence of basic beliefs by appeal to examples. My belief that I have a headache, or that I feel thirsty and warm, is not based on any belief but simply on an awareness of the experiences themselves. I don't seem to hold these beliefs on the basis of other beliefs. My belief that there are no round squares, or that circles don't have corners, is not based on other beliefs, but on something like a clear understanding of the concepts that figure in the belief or a clear grasp of the nature of the properties the belief is about. These foundational beliefs seem to be based on introspection and reason respectively. Many contemporary foundationalists expand the sources of foundational justification to include sensory perception and memory. A very permissive sort of foundationalism, sometimes called phenomenal conservatism, holds that the mere fact that it appears or seems to me that p would provide me with some reason or justification to believe that p. Although most contemporary epistemologists are foundationalists of some sort or other, virtually all epistemologists accept something roughly like a coherence constraint on justification, a "no defeater" condition. In addition to having positive, inferential or non-inferential justification for some belief that p, the subject must (a) not have good reasons to think that ∼p (sometimes called a "rebutting defeater") and (b) must not have good reasons to think that one's belief was formed in an unreliable way or on the basis of an unreliable source (sometimes called an "undercutting" or "undermining" defeater). Suppose I believe that there are fish in the neighborhood pond, and suppose I have a good reason or justification to think this (e.g., an honest neighbor's testimony). If I also have reason to think that there aren't any fish in the pond (e.g., another honest neighbor's conflicting testimony), or a reason to think my evidence is misleading or my source is unreliable (e. g., knowing that my neighbor's testimony is unreliable), then the belief is not rational. Thus, the satisfaction of positive conditions for non-inferential and inferential justification is not sufficient for justified belief; such a belief is "defeasibly" or "prima facie" justified, where this just means that it is justified in the absence of defeaters. In addition to the foundationalist-coherentist debate, there is the internalist-externalist debate. There are in fact multiple debates that fall under the latter label (see Conee and Feldman 2001), but we will focus on the debate between access internalists and access externalists (henceforth simply "internalism" and "externalism"). This debate can be understood as a disagreement regarding the appropriate way to understand the relation between epistemic justification and truth. Internalists take epistemic justification for believing that p to require having access to good reasons to think that p is (probably) true. Externalists deny this. Externalists require that there be some "external" connection to the truth or probability of the belief. For example, according to one of the most popular forms of externalism, reliabilism, epistemic justification requires that one's belief-forming methods Doxastic Foundations: Atheism THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY 121 or processes be reliable-roughly, that they yield true beliefs more often than not. Externalists usually also require the absence of defeaters: having reasons to think p true is not required for justified belief that p, but not having reasons to think the belief false or untrustworthy is. Internalism is initially plausible and very intuitive. One way to motivate it is by appeal to hypothetical cases like Lehrer's (1990) case of Truetemp, who, without knowing it, has a chip implanted in his head that produces very precise and highly accurate beliefs about the ambient temperature. Truetemp often gets temperature beliefs from the operation of the chip, but he has never checked their correctness and has no reasons for, or against, his having such an ability. Truetemp's belief that the temperature is now exactly 47 degrees is produced by a highly reliable process, in the absence of defeaters. But intuitively, it is not justified. Reflection on this and similar examples suggests that internalism is right about what is missing: although these beliefs are objectively probable, highly reliable, track the truth, or satisfy some such external requirement, there is nothing within the subject's perspective that indicates this, no reason for the subject to take the belief to be true. Externalists themselves often admit that internalism is intuitive. But they worry that the internalist faces a dilemma. If the internalist accepts that there must be a strong connection between epistemic justification and truth (or probable truth), then the demand of access to that connection is too high, with the consequence that few if any of our beliefs are justified. If, however, the internalist says that no such connection is required, or only a weak one, then epistemic justification is not tied to the truth in any significant, objective way. These debates are complicated. There are proponents of internalism and externalism, foundationalism and coherentism, on opposing sides of the theism/atheism debate, and, as we'll soon see, some defend the rationality of theism by relying on a particular epistemological theory. None of these epistemological views obviously or trivially favors theism, atheism, or agnosticism. However, when we consider whether there are defeaters for theism, we'll find a strong case for denying that theism is rational on any plausible account. EVIDENCE AND EVIDENTIALISM The concept of evidence figures prominently in contemporary epistemology and is closely related to other epistemic concepts. But how, exactly, is evidence related to rationality, and how does it figure in the foundationalist-coherentist and internalist-externalist debates? One very neat and intuitive way to connect talk of evidence and rationality is to accept evidentialism, roughly, the view that rationality requires having beliefs that fit the evidence. "Proportion your beliefs to the total evidence!" is a good evidentialist slogan. Roughly, E is evidence for p if and only if E raises the probability of p. One's "total evidence" might involve (a) evidence that is neutral with respect to p; (b) evidence in favor of p or evidence that raises the probability of p; (c) evidence in favor of ∼p or evidence that lowers the probability of p (defeaters). In order for some evidence E to make a difference to the rationality of S's belief that p, S must in some way possess or have access to E. Evidentialism is thus in line with some form of internalism. However, it is plausible that S must also in some way grasp or understand the relevance of the E to the probability or truth of p; being aware of something that has an objective connection to the truth of p, but where one has no grasp of that connection whatsoever, seems no better than not being aware of it, and so the mere requirement of access to E seems to not be in the spirit of (access) internalism. Many contemporary evidentialists are foundationalists who hold that we can have evidence by having non-doxastic states like experiences. (Conee and Feldman 2004). My belief that I feel thirsty and warm is not based on any belief, but simply on an awareness of the experiences themselves, and it would be odd to say that I have no evidence that I feel this way. In the epistemology of religion, and in particular the evidentialist-reformist debate, "evidentialism" is sometimes used to stand for the view that, roughly, rational belief in God requires having a good argument for God's existence or can be justified only inferentially if at all (e.g., Plantinga 1981). It is important not to confuse this view, which we might call "doxastic evidentialism about belief in God," with evidentialism as a general theory of rationality. Some might be evidentialists Doxastic Foundations: Atheism 122 THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY (belief must fit the total evidence) but hold that belief in God can be basic by being based on nondoxastic evidence like a direct perception of God, and some might deny evidentialism (deny that all rational beliefs require evidence) but think that belief in God does not satisfy conditions for noninferential justification and so must, like scientific beliefs, be justified by some argument or inference. A complication arises when we ask how much evidence is required for belief or how probable the proposition must be given one's total evidence in order for it to be rational to believe the proposition. A probability of 1 (certainty) is surely too high, slightly above 0.5 is too low, and any particular probabilistic measure in between these values seems arbitrary. A natural move is to appeal to the idea that belief itself comes in degrees. Perhaps the distinction between believing, disbelieving, and withholding belief is a useful but rather coarse-grained and potentially misleading simplification; the attitude of belief can be put on a scale, with different degrees of confidence or "credences" varying from full belief (an attitude of absolute confidence in the truth of the proposition), full disbelief (an attitude of absolute confidence in the truth of the negation of the proposition), and degrees between these two extremes. The evidentialist can then claim that one's credence must fist the evidence. In what follows, however, we can leave open the question of whether belief comes in degrees or not. Those who deny that belief comes in degrees can understand talk of the rational degree of confidence to have in p in terms of degree of probability that it is rational to believe p to have. Is it rational to believe that God exists? Some may hold that it is rational to have full belief, or the highest possible confidence, that God exists. Some might deny that, but hold that it is rational to have a significantly high degree of confidence, perhaps high enough that it more or less matches the degree of confidence it is rational for us to have in commonsense beliefs and our best, most stable, and well-tested scientific theories. More modestly, some might say that it is at least rational to have significantly greater confidence that God exists than not. I argue against taking theism to be rational even in this minimal way. BRACKETING SKEPTICISM If an argument that belief in God is not rational depends on a particularly demanding theory or standard of rationality, one with radically skeptical consequences, then the theist is likely to object that the standard is too demanding or that theism has at least not been shown to be any less rational than common sense or the best scientific theories. Let us accordingly bracket the issue of skepticism, as David Hume did in his famous dialogues (2007); let us grant for the sake of argument that radical skepticism is false in assessing whether belief in God is rational. Classical or traditional varieties of foundationalism tend to be demanding in at least one way, or possibly two: (a) being very restrictive about the sources of basic belief (e.g., holding that reason and introspection can be sources of basic belief, but perception and memory cannot); (b) requiring epistemic certainty or infallibility for basic belief. Many worry that either requirement greatly limits the basic beliefs and leads to radical skepticism. Classical foundationalists think the demands appropriate, and some hold that radical skepticism can be avoided (Hasan and Fumerton 2016). But many others are not convinced. Since we are bracketing skepticism, however, let us avoid appealing to any requirements of rationality that seem to have radically skeptical consequences. WHY THEISM IS NOT RATIONAL Even if we bracket radical skepticism and assume the rationality of our ordinary, commonsense beliefs regarding the external world, we may have good reasons to deny that the belief in God satisfies appropriate requirements of rationality. As we shall see, although there are some serious concerns with theism's satisfaction of positive requirements for prima facie justification, doubts regarding the satisfaction of the negative, no-defeater requirement, have the widest and strongest impact. INFERENTIAL JUSTIFICATION FOR THEISM? When someone claims that belief in God is not rational because it is not supported by good arguments, theists often respond that they do have good arguments. There are the traditional arguments Doxastic Foundations: Atheism THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY 123 for the existence of God, including various versions of the cosmological, teleological, and ontological arguments. We cannot examine the specific arguments here. However, it is worth noting that philosophers who study these arguments for a living, even the theists among them, disagree regarding which, if any, of these arguments are sound or cogent. This is no surprise, for, as any student of philosophy of religion quickly discovers, the arguments are complex and abstract, and many of the key premises are controversial or depend on further complex arguments. Perhaps these traditional arguments are not the only way. Perhaps there are special signs of God around us. But what signs might these be? Miracles? Confirmed prophecies? Speaking for myself, I have not observed any miracles, at least not in the sense of something that clearly requires a supernatural explanation, let alone the existence of God. And I have not observed any shockingly accurate prophecy that could not be explained away. Moreover, while others might claim to have made such observations or have some special expertise or source of religious knowledge, there is a great deal of disagreement among them, and no good, independent way to determine which of them are reliable. Since all the main accounts of rationality accept no-defeater requirements, there is no escape from the problem that significant disagreement about these inferential sources undermines reliance on them. REFORMED EPISTEMOLOGY AND BASIC BELIEF IN GOD When someone claims that belief in God is not rational because it is not supported by good arguments, some reply in a different way, by denying that argument is needed at all. According to "reformed epistemology," belief in God can be basic, not just in the sense that it is not based on any other belief, but in the foundationalist's sense that it is non-inferentially justified without depending on any other belief for its justification. (To signal this difference, some reformed epistemologists call the latter a properly basic belief.) Reformed epistemology can be understood as granting, at least for the sake of argument, that we do not have adequate evidence-at least not doxastic or inferential evidence-but claiming that no such evidence is required for rationality. Could belief in God be (properly) basic? Some beliefs are basic because they are self-evident, where this means, roughly, that the truth of the belief is obvious to anyone who genuinely understands it. It is self-evident to me that there are no round squares, and that 2 + 2 = 4. While we can allow for some variation when it comes to what is self-evident to different people, we have very good reasons to strongly doubt that belief in God could be self-evident to us in this way. I seem to have no difficulty in understanding the thought that God exists, and yet I can still wonder, quite intelligibly, whether it is true. Some foundationalists hold that ordinary, sensory perception can be a source of non-inferential justification. Perhaps, as held within the Reformed tradition in Christianity, we were created with a special sort of perception, an inner sense or awareness of God, a sensus divinitatus, that is activated in certain circumstances, disposing us to believe in God. So perhaps religious experiences of various sorts can justify my belief that God is present, is speaking to me, forgives me, or has created all of this. Willian Alston and Alvin Plantinga have each defended reformed epistemologist accounts of basic belief in God. William Alston argues that religious belief (and specifically, Christian belief) can be justified by religious experience or religious belief-forming practices, just as perceptual belief can be justified by perceptual experience or perceptual belief-forming practices. To provide justification, the experiences or practices in question must be reliable and so constitute a good ground of sorts, and the subject must lack defeaters, but the subject need not have justification for believing that it is reliable (see Alston 1983; 1991). According to Alvin Plantinga, a basic belief must be produced by a properly functioning and reliable cognitive faculty, in an appropriate environment, the sort of environment for which the faculties were designed, whether by God or evolution. A belief in God that satisfies these conditions is properly basic (absent defeaters) (see Plantinga 1981; 1993). Some theists accept even weaker requirements for basic belief. For example, some are phenomenal conservatives who hold that its seeming or appearing to me that God exists is sufficient, absent defeaters, for justification (Tucker 2011). Doxastic Foundations: Atheism 124 THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY Alston and Plantinga are both externalists, for they deny that one must have some reason to think that one's belief is reliably produced, the output of a properly functioning cognitive faculty, or that one has in some other way a reason to believe it. As we discussed, externalism seems to have strongly counter-intuitive consequences. However, internalism has difficulties avoiding skepticism while retaining a robust connection between justification and truth. In any case, externalism is popular among many epistemologists, including many atheists. One might object that religious belief-forming practices are unlike perceptual ones in that they are not widely shared. But the fact that a method is not widely practiced does not show that it is unreliable. To require that any practice be like sense perception in being universal or more widely shared is a version of what Alston calls imperialism-insisting that what holds of perceptual practice must hold of religious or mystical practice, without good reason. Another objection is that religious practice is not independently verifiable. There is no way to test whether its deliverances are right. It seems that we need some prior and independent reason to trust the practice, source, or method, one that does not depend on the very practice, source, or method being assessed. Reformed epistemologists would here join other externalists in raising the worry that accepting this as a general requirement is too demanding. Suppose that we could not rely on perception, memory, introspection, or reflection unless we already had reasons to believe that these sources are reliable. The problem is that, given that we have a finite number of sources, any such reason must itself be the output of at least one such source, and so the need to already have a reason to trust the source arises once again. There is no noncircular way to defend the reliability of our sources of belief. To hold that one does not require a noncircular justification of reliability for ordinary perceptual sources but requires it for religious sources is an instance of what Alston calls a double standard. There are, however, other more serious concerns. We have alternative explanations for why we have these religious beliefs and the apparent experiences that support them (see Fales 1996). First, prior beliefs might be the cause of the experiences rather than the other way around. Second, there is no denying the comfort and psychological benefit that many believers derive from their faith, the emotional attachment they are likely to have to the possibility of a relationship to God, and the difficulty of giving up beliefs one was raised to take for granted. There is also the problem of conflicting results of religious or mystical experiences. If all religious or mystical experiences depend on the same source or process, then this source or process is unreliable because it leads to conflicting results. If we distinguish between the sources or processes in some way, then the question arises: Which of these sources or processes should we rely on? "Rely on the reliable ones!" is not helpful when we have no independent way of distinguishing between the reliable or unreliable ones. We ought, therefore, to refrain from trusting any of them. These criticisms can grant, for the sake of argument, that believers in fact satisfy the external conditions for prima facie justification proposed by reformed epistemologists like Alston and Plantinga. However, they provide us with reasons to doubt that we satisfy the no-defeater condition, for we have good reasons to think that any religious and mystical experiences we have are unlikely to be reliable. THE PROBLEM OF DISAGREEMENT GENERALIZED Each of the two preceding sections ended by raising concerns regarding the reliability of (a) inferential and (b) non-inferential sources of justification. We are now in a good position to state the argument in a general way that affects any account of the rationality of theism, whether internalist or externalist, foundationalist or coherentist, so long as the account accepts a no-defeater condition on rationality. I was raised Muslim, in a Muslim country, and immigrated to the United States in my early teens. I recall riding a bus to school, looking around at all the other passengers and thinking to myself: I am awfully lucky to have been born into the one true faith. People, by and large, tend to hold the religious beliefs of their parents or culture. Most children of Muslims, Christians, Jews, Hindus, Sikhs, and so on, tend to accept and remain believers of their parents' faith, and these faiths say different, incompatible things. If all these believers, even the intelligent and thoughtful among them, share a religious belief-forming practice, that method is highly unreliable. If there are many Doxastic Foundations: Atheism THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY 125 different methods of religious belief-forming practice, then perhaps my belief is reliable after all. However, that would be awfully lucky, and continuing to believe in my religion would be arbitrary and dogmatic. I can be justified only if I have a good reason to take my religious belief-forming method to be better. Surely it is possible to rationally disagree with someone! Yes, of course. If you tell me that there are round squares, or that circles have corners, or that 2 + 2 = 17, I'm not going to suspend judgment, or even lower my confidence in any significant way. I'm much more likely to think you are playing some kind of prank on me, or trying to see how I would react, and sooner or later, if you persist, I may begin to wonder about your sanity. This would all be rational for me. So we don't, and shouldn't, always budge in the face of disagreement-at least not significantly. But belief in God is not like belief that there are no round squares or that 2 + 2 = 4. Disagreement about God is more like the following case (see Christensen 2007): Suppose we have just finished a meal at the restaurant and decide to split the bill evenly. We each calculate how much we owe. I come up with $23, and you $21. Suppose we each know that the other person is generally just as good at such calculations, and nothing seems different in the present case. After finding out that you get a different-incompatible-answer, it seems it would be epistemically irrational of me to hold steadfastly to my answer and believe that you made an error and I didn't, or that it is significantly more likely that you are wrong. It seems rational for me to suspend judgment. At this point, one might object: If the problem of disagreement is a genuine problem, doesn't it affect all sorts of beliefs, including ordinary and scientific beliefs, and so result in skepticism? No. First, people by and large agree with respect to a great deal of ordinary and scientific belief. Second, as just discussed, there are various beliefs we hold that are justified to such a high degree that we would be justified in dismissing others' disagreement, justified in taking them not to be in as good an epistemic position as we are, even if we can't initially see exactly why. However, won't such a view still have a strongly skeptical result at least where there is significant disagreement, including in science and philosophy? Well, let's think about these sorts of disagreements, on such topics as the freedom of the will, the nature of time, or competing interpretations of quantum mechanics. When it comes to such open disagreements between philosophers or scientists with similar abilities, who seem to have the same evidence or have closely examined the same arguments, it makes sense to say that they are not (at least not yet) epistemically rational in believing theirs is the correct theory. Does this mean we should stop doing physics or philosophy, or stop taking our research seriously? Of course not. There may be many good reasons to continue to develop and defend one particular theory over another, or take it as a "working hypothesis," including for the sake of furthering future knowledge and understanding in our field, and finding important points of agreement. But this should not be confused with being epistemically rational in believing one theory over another. The reader might have a final worry: But won't philosophers disagree with your conclusion and how you came to it? And if so, shouldn't you suspend belief about whether these are genuine defeaters, in which case the defeater is defeated? The first thing to notice is that this is a disagreement that occurs one level up: it is a disagreement about whether I am rational in believing that theism is defeated by significant disagreement about religious matters. That would not take away the fact of disagreement at the first level. And that seems to be enough to generate the problem. Compare the restaurant case again: Suppose you initially react to the different calculations of the bill by suspending judgment. Suppose you then find out that there are philosophers who disagree about whether that's the rational attitude to hold. Does that suddenly make it epistemically rational for you to believe that your calculation was correct and mine is not? Surely not! Let us take stock. We began by considering possible inferential and non-inferential sources of rational belief in God. In each case, we considered undercutting defeaters, reasons to doubt that these sources were reliable. We spent some time discussing the strongest reason, the problem of disagreement regarding the existence and nature of the divine, and the existence of competing beliefforming practices. That there is this sort of disagreement and divergence in religious belief-forming practice is available to most if not all ordinary adults today. We should conclude that the case against the rationality of theism, while defeasible, is quite strong. Doxastic Foundations: Atheism 126 THEISM AND ATHEISM: OPPOSING ARGUMENTS IN PHILOSOPHY