Why Believe That God Exists?

Many of us who believe there is a God vacillate between an implicit dogmatism, the view that the evidence is overwhelming, so that it is more or less obvious that God exists, and thus only the foolish, obtuse, or wicked fail to believe, and an implicit fideism, the view that one does not need reasons to believe, that it is for some reason perfectly proper to believe in the absence of justification so long as one’s belief bears the label “faith.” A third approach, which seems to be a species of fideism, embraces—or feigns—a relativism on which standards of justification are somehow decided upon by communities of believers.

However, at the end of the day, if one doesn’t have good reasons to believe, then he ought not to believe. Persistent belief in the absence of justification shows a lack of concern with one’s beliefs being true. One may instead hope that something is true, but this too requires good reasons, though the standard for rational hope is lower than that for rational belief. Remove rational justification altogether, and we’re left merely wishing. It is at times and in some ways rational to act on our hopes, but it is not rational to act on the basis of what we merely wish were true. Few believers are happy with the idea that evidence really is needed and that it is “just about” good enough, but it seems to me to be that the rationally required justification is available, but just barely; indeed, it might be that we’re left somewhere uncomfortably close to the indefinite boundary between rational belief and rational hope. Perhaps the best we can get is deniable plausibility. (Perhaps this is mitigated by the fact that belief in the modern sense, i.e., as a propositional attitude, lies only at the margins of the biblical concept of faith in Christ.)

Christian faith is not unjustified belief; at least it ought not to be. It is trust in the God who resurrected Jesus of Nazareth. Trust in someone might be either reasonable or unreasonable. E.g., I have faith in my wife and I have good reasons for that faith, i.e., for trusting her. We ought not to put our trust in someone unless we have good enough reasons to do so. A stranger approaches me in the street and asks for a loan, saying I should trust him to repay. Probably, such faith would be irrational.

So, do we have good enough reasons to trust in the God of Christianity? Trusting a person appears to presuppose the belief that he exists. What are the reasons that justify theistic belief? I know of two lines of reasoning, one highly abstract and one that appeals to the particulars of history.

I The Abstract Argument

(1) If an explanation maximizes feasible intelligibility, then it is reasonable to believe it.

(2) That the universe exists as the result of the free choice of a rational, necessarily existent being maximizes feasible intelligibility.

Therefore, it is reasonable to believe that this contingent universe exists as the result of the free choice of a rational, necessarily existent being.

Comments

1) By maximizing feasible intelligibility, I mean that the explanation offers the highest degree of intelligibility consistent with what we know. There are explanations of why the universe exists that afford greater intelligibility than the theistic explanation, but they are not feasible because they conflict with things we know—or at least think we know—to be true. For example, if the universe were found to be a necessary existent, that would accord its existence the highest conceivable degree of intelligibility, but we have good reasons to believe that the universe is a contingent, not a necessary entity. I take modern, empirical science to presuppose that neither the boundary conditions, nor the fundamental laws, of the universe are necessary, which is why they are knowable only by way of empirical inquiry.

What of explanations of why this universe exists that grant its contingency but portray its existence as dependent on something that necessarily exists? If the universe is some sort of necessary “emanation” from this necessary entity, then it is no less necessary. If it exists because something like natural laws entail its existence, we have to ask whether these law themselves are necessary, or contingent, truths. If they are necessary, then this universe necessarily exists. If they are contingent, this world is contingent, but then we must ask why these laws are true. Similarly, if this universe exists in virtue of some random event in the necessary being (assuming this is a coherent possibility). To acknowledge that this universe is contingent—it did not have to exist—and that it does not exist for good reasons, is to admit that its existence is simply unintelligible; there is no explanation of its existence. It exists as a matter of “brute fact.”

On the other hand, we can explain what happens as the free choice of a rational being. The idea of uncaused free choice (libertarian free will, agent causation) makes sense as a possible explanation of why something happened:

This happened because this person had good reasons to make it happen, and for those reasons chose to make it happen, and thus made it happen.

This renders the occurrence intelligible, even though, on the assumption that the agent possesses libertarian free will, those reasons neither metaphysically, nor causally, necessitate the choice to bring that thing about. Necessity maximizes intelligibility, but something coming about because an agent cause chose, for good reasons, to bring it about, renders its occurrence intelligible, albeit to a lesser degree. And this affords a higher degree of intelligibility than regarding something as a matter of chance, or as brute fact.

Theism supposes that this universe exists as a result of the free choice of a rational person. God brought this universe into existence for good reasons, but nothing necessitated his doing so. (This does not imply, and I do not, as it happens, believe, that human beings possess libertarian free will. I suspect it is impossible for a physical being to be an agent cause. I assume instead that human beings are fully enmeshed in the causal order of nature, but that when things go well we develop into good simulations of agent causes.)

2) This little argument has some significant liabilities:

a) There is no guarantee that reality cooperates with human hopes for intelligibility. Our minds are in large measure the product of natural selection in an environment in which assuming there were causes of, and thus explanations for, what happens enhanced the odds of being around long enough to reproduce and to send genes that build neural circuitry that sustains the assumption that things don’t just happen, but have a rational explanation, to the next generation. The quest for intelligibility might, for all we know, be fruitless when directed to the universe at large because reality is not, at bottom, intelligible, even though the ancestral human environment was a close enough approximation to intelligibility to select for creatures wired to make it their default assumption.

The quest for an intelligible universe has twice been forced to lower its expectations and settle for a lower standard of intelligibility: Science in the modern sense emerged only when Aristotelian “demonstration” was abandoned as the criterion of an adequate explanation, in favor of explaining things by subsuming them under contingent laws. (As it happened, it was late medieval theology’s reflection on divine providence that made this possible.) Later, in the 20th century, giving up the supposition that nature’s basic laws are deterministic, in favor of the Copenhagen interpretation of quantum mechanics, was to settle for an even lower standard of intelligibility. The lesson is that our demands for intelligibility have been too stringent, and they might be in this context as well, and that the very existence of the world is intelligible only on a lowered standard.

b) This line of reasoning presupposes the legitimacy of talk of de re modalities. In describing the universe as a contingent entity, and postulating a necessarily existing person to explain its existence, we assume that necessity and contingency are not merely features of our language, or our conceptual schemes (modality de dicto), but applicable to things. This assumption is controversial.

c) The argument depends on the assumption that the observed universe actually is contingent. It is conceivable that this is false. The greatest conceivable unification, the unification of mathematics and physical science, would defeat this argument. In that scenario the basic laws of physics like e=mc2 would be no less necessary than mathematical truths like 1 + 1 = 2. Perhaps we already see intimations of this in quantum mechanics, where abstract mathematical structures are in some ways treated as physical realities (Hilbert spaces, probability waves.)

d) It also depends on there being an objective difference between the possible and the actual; if modal realism is true, and the other possible worlds are no less real than this, what we call the actual, world, the argument fails.

e) This reasoning presupposes that there is a necessarily existent being which has a distinct character. I am, of course, at a loss to explain how a necessarily existence entity can be a concrete particular, as I assume God is, as opposed to an abstract object, let alone to explain how it can be a person, indeed a person who exercises libertarian free will.

This is at odds with the common supposition that matters of necessary truth, even when highly complex, are fundamentally straightforward, regular, bland, monolithic, predictable, uninteresting, etc., and that anything unique, individual or unexpected, anything with “character,” belongs to the realm of contingency. Yet this assumption does not survive an encounter with the domains of necessary truth we best understand, viz., logic and mathematics. Here what becomes apparent is that the realm of necessity is inhabited by things—whatever they are—which have quite particular, unexpected, and often plain “quirky” natures. Consider the endlessly surprising discoveries in number theory, e.g., facts about the distribution of the primes, or the profoundly counterintuitive properties of cellular automata, the bizarre zoo of objects generated by a few simple rules from a simple beginning. These are arenas in which what’s true is what must be true, yet what’s true is often very far from anything we find simple or obvious. I don’t know how to put this sense of a connection between necessity and unique character clearly, let along construct a natural theological argument from it, but without it I would find it harder to take seriously the idea of a necessarily existent free person. I conjecture that these things we discern as the characteristics of such abstracta as sets, numbers, cellular automata, and so on, somehow are just a pale reflection of the concrete necessary reality of the divine logos himself.

***

Overall, I do not suppose that this argument compels rational belief. It shows that belief in a personal deity who is a rational free agent is at least reasonable, in accord with our deepest intellectual aspirations. Still, the argument involves quite a bit that someone not already inclined to believe in the plausibility of theism may well find hard to swallow, as well as things I am not sure of. Still, its principal attraction seems to me clear. We face a trilemma:

The world as unintelligible brute fact

The world as necessary

God (a necessarily existent being freely created the world for good reasons)

Of the three horns, we have a large stake in rejecting the second in favor of the world’s contingency. And we can reasonably suspect that the first is not the case. The idea that this world is intelligible yet contingent stands at the heart of science, our most reliable way of knowing.

I know of no other natural theological arguments that get us anywhere. The only other line of reasoning that has any promise is the appeal to cosmological fine tuning, but this inference to divine design is not obviously more plausible than the anthropic reasoning that explains the fine tuning by describing our universe as one of many.

I believe that God created this universe with a view to bringing into existence, by way of somewhat indeterministic natural processes, personal creatures he could invite to share in the everlasting, joyful life of the Trinity. I believe that it was always a part of God’s intention to be incarnate in his creation and as such to be empirically present to his creatures and to be subject to being accepted or rejected by them. I have no reason to suppose the world should contain clear evidence that God created it, or that God even exists, other than his actual presence in it as one of us.

Like other exercises in natural theology, this argument, even if sound, brings us to a “generic theism,” not explicitly to the God of Abraham, Isaac, and Joseph, the God who resurrected Jesus of Nazareth. However, it exhibits a winsome coherence with the specifics of biblical faith. For it explicitly claims that there is a God who freely created this world for good reasons, while the Christian faith’s central claim is that God freely created this world for a good reason, viz., for the sake of created persons with whom God can share his triune life.

II The Historical Argument

This line of reasoning differs sharply from the abstract argument. That argument looked to the world at large and what seems to follow from its assumed contingency and intelligibility. This two-part argument looks to the complications of history:

Part One

Premise 1: In the late first and early second century CE many persons believed that Jesus of Nazareth had been resurrected.

Premise 2: The best explanation of this historical fact is that Jesus was resurrected.

Premise 3: If something is the best explanation of something, then it is reasonable to believe it.

Therefore: It is reasonable to believe that Jesus of Nazareth was resurrected.

Part Two

Premise A: If Jesus of Nazareth was resurrected, then it is reasonable to believe that God exists.

Premise B: It is reasonable to believe that Jesus of Nazareth was resurrected.

Therefore: It is reasonable to believe that God exists.

Comments

Obviously, a great deal depends on Premise 2. Its defense requires examining the “it was true” explanation against all competing explanations and justifying the conclusion that it is the best. In the ideal, we’d show that it’s the only possible, or only reasonable, explanation, but I assume that that would be very difficult to do. Indeed, it is difficult enough to make the case for the weaker claim. But I believe that that case can be made. See, for instance, N. T. Wright’s magisterial, The Resurrection of the Son of God (Fortress Press, 2003.)

Further, the first stage of the argument suppresses an assumption that needs to be made explicit. Any abductive argument—inference to the best explanation—at least implicitly involves two claims:

X is the best explanation of Y

X reaches some threshold of plausibility

Thus an abductive justification is a two-stage process. For it is possible that something is the best explanation of something, yet the reasonable course is not to accept it, but to shrug one’s shoulders and say, “Who knows? There must be some explanation, but none of those we know of are plausible enough to believe.” Suppose (contrary to fact) that we consider all known explanations for “crop circles” and eliminate all of them except for their being the work of extraterrestrial aliens. I don’t think it would be reasonable to believe that this phenomenon is due to ETs. The best explanation still might not be good enough.

Someone might come to agree that the best explanation of people believing that Jesus was resurrected is that Jesus was resurrected, but still find this explanation too implausible to accept, and settle for there being no adequate explanation for the historical events in question. The judgment that Jesus actually having been resurrected is the best explanation of what we know happened in history is one we can reasonably hope to justify on objective (i.e., public) grounds, though doing this is difficult enough. The further judgment, that the theistic explanation is not just best but also good enough, is categorically far more difficult to justify, especially in our late modern culture, where the existence of supernatural agents of some sort or other is not taken for granted. An individual’s judgments of antecedent plausibility are subtly and intricately connected to many other things she believes, and beyond that to her values, hopes, personal history, and so on. This is not to retreat to the claim that these judgments are, in the end, merely subjective, irrational, or a matter of choice. It is to acknowledge how complex and inchoate are the grounds for some of our most important beliefs. These matters can, in principle, be treated objectively, i.e., our views on what is, or isn’t, antecedently plausible are proper matters of ongoing public, critical debate. In this regard they are of a piece with many of our most important beliefs, e.g., various philosophical, ethical, political, and aesthetic judgments where we regard ourselves as rationally justified, while acknowledging that other persons, viewing things from other perspectives, may rationally disagree.

What I above called the Abstract Argument now comes into play. We can more readily believe that Jesus really having been resurrected is a plausible enough explanation to accept if we have independent reason to believe that there is a God who could resurrect him. At the same time, any reason to believe that Jesus was God incarnate, vindicated by resurrection, fits with the idea that there is a God who created the world for a reason, viz., in order for there to be created persons with whom God can share his triune life. God becoming part of his creation would be the epitome of God sharing his life with us. (Unlike many other Christians, I believe that God always intended to become incarnate; the incarnation would have occurred even if there had been no need to reconcile “fallen” creatures to God.)

More could be said here, perhaps particularly on behalf of Premise A—If Jesus of Nazareth was resurrected, then God exists—but what I have set out is what I see as the central reason to believe that God exists: Jesus was resurrected. Unlike most other theists, who think we have good enough reasons to believe there is a God independent of the life, death, and resurrection of Jesus, I think rational belief in God today stands or falls on the historicity of the resurrection.

Finally, because we are material beings, there is no reason to believe that in the natural course of events we will live after we die. The only reason to believe that we will be resurrected is that Jesus was miraculously resurrected, and that the God who resurrected him promises to resurrect all those who by grace through faith are united with him.