It is irrational to believe that the Christian God exists.

Epistemic Nihilism

Philosophically, this is about whether it is in principle irrational to believe in God; we can formulate this as: “Can we know that God does not exist?” The epistemic question is important because, if it is possible to have knowledge that God does not exist, there would be no justification for “settling” on theism. Hence the distinction between atheism, a metaphysical commitment to non-belief, and agnosticism, an epistemic commitment to non-knowledge. I want to take up the task of the epistemic nihilist: exposing the impossibility of certainty. If I can convince you that one cannot have any knowledge, much less of a divine entity, I submit that one cannot call it “irrational” to place faith in God. One may be tempted to counter that the inability to know makes atheism as irrational as theism, since one is claiming certainty in both cases; however, my case, dealing with faith in God, excepts me from this objection precisely because the nature of faith is commitment to something being true sans certainty (i.e., since faith in God is, definitionally, belief without knowledge-claiming, one cannot object to my case on the basis that some theists do claim knowledge of God).

Note, this is about philosophical rigor, rather than mere practical concerns. As Hume might put it, we cannot have knowledge that the sun will rise in the morning—the Earth could explode or stop spinning; the Sun could fizzle out or fly out of orbit; demons could pop out of some higher plane of existence and steal the sun for sustenance. We can’t rule out such possibilities, no matter what probability score we try to assign them. Yet, it is nevertheless practical to retain our expectation that the sun will rise tomorrow, because our brains and daily lives leave us little choice.

So, let’s investigate what we use to arrive at truth claims. Our primary tool is the justification, In this process, we demonstrate the truth of a proposition by gesturing to an external referent. If I claim to have brown hair, I might justify this by meeting you in person. Or, if I claim that all dogs have hair, I might structure my argument this way: “All mammals have hair. Dogs are mammals. So, dogs have hair.” This is why the classical idea of knowledge—as “justified true belief”, barring Gettier cases, etc.—is so-formulated.

For the nihilist, this is problematic. If every true proposition must be verified by reference to an exteriority, chains of justification eventually reach a point at which a proposition must be acknowledged as unjustifiable. Anyone who has endured a young child’s endless questioning is familiar with this frustration. The problem manifests in three ways, articulated as Agrippa’s (or Munchhausen’s) Trilemma. On this view, justificationalist attempts to gain knowledge are always doomed by one of the following conditions:

1. Infinite regress: given proposition P1, justify with P2. Justify P2 with P3, P3 with P4, ad infinitum. In other words, if all propositions require justification, the chain of exteriorities required to continue justification will stretch out infinitely.
   
2. Vicious circularity: two propositions, A and B, rely upon each other for justification, establishing an endless loop of other-justification. That is, “A can be justified by reference to B; B can be justified by reference to A.”
3. Axiomism: some particular proposition—P—at the "end" of a justificatory chain is asserted as self-evidently true, or is taken as given/assumed. “Given X, Y.” Alternatively, “X is useful/non-X is inconceivable; therefore, act/reason as if X.”

One might see how this affects our ability to make knowledge claims. We can do some interesting footwork here. A fallacy often attributed to believers is the “You cannot disprove God” argument. Despite dubios conclusions associated with this statement, the argument per se is difficult to contend with. One really cannot determine whether a God exists. With all our experience of the universe, all the space we’ve observed, and all the observational equipment we use, we can never say “I have found that there is no God.” The best we get is “I have not yet found God”. On the one hand, we are forced to acknowledge that it is in principle an impossible task—one can always imagine having not looked somewhere, not having had some instrument, etc. One can even imagine finding God, and not recognizing him. While we might have some idea of what God is “supposed” to be like, nihilism forces us to make the following concession: we are barred from knowing not only whether God exists, but also anything about what God is like.

For this debate, I accepted omni-God (omnipotent, omniscient, omnibenevolent). Certainly, we might have ways of defining these terms (omnibenevolent as “all-loving”), but, for the nihilist, a problem remains. What does it mean to say that God is any of these things? We can assign these words—love, potentiality, knowledge—a specific meaning, but we cannot be so sure that our understanding corresponds to God’s nature. A frustrated and scared person might ask, for instance, “Why would a just and loving God stand idle while I get assaulted?” There, we see the way in which profane understanding of love and justice imposes itself upon God, reconfiguring the ius divinum as a mere extension of human institutions. Even with stipulated definitions God, the content of the definitions is subject to nihilistic limits. More than being unable to know whether God exists, we cannot, given his nature as a divine being, meaningfully discern what his attributes are. We cannot know what it means for God to “love all”, or to “be able to do anything”, or to “know all that can be known”. We have definitional templates, but arguments like the paradox of the stone, the problem of evil, divine foreknowledge, etc. demonstrate how we are forced to “fill in the blanks” in God’s nature when it comes time to talk about his ontological status.

Stipulating an idea of God, then, is only an attempt to avoid the vast knowledge problems by taking the axiomist route: “Given O3 God…” But, as soon as we regard specific conceptions as axiomatic, and take the theist exit (placing faith in this conception, and its instantiation as the Christian God), you’re above questions of rationality and irrationality—first, because of the nature of faith. If you never claim to have certainty or to prove anything, you are, for better or worse, exempted from “rationality” constraints. Second, taking the axiomist route automatically exempts the proposition in question from arguments over rationality, because rationality deals with derivations, not first principles. It is not “rational” or “irrational” to place one’s confidence in the unproven proposition that A is A, for instance—rationality is judged precisely by conformity to this axiom. This can be mimicked by the theist as: “I don’t know that God exists—but I have faith that He does.”

Concluding with a return to my earlier remarks on my task, the direct relevance of the above reflections emerges:

1. Because of regression problems, we cannot have certainty about anything, including God’s existence and properties, or that what we perceive and interact with is “objective reality”—even the proposition that we cannot have knowledge is subject to this constraint. Supposing Pro makes the “nihilism is self-refuting” objection, I am prepared to deal with it. I do not have the space here.
2. Taking the axiomist route, in which one commits to faith in a particular conception of God, exempts one from discussions about rationality and irrationality by situating the proposition at the level of a starting point, rather than a derivation (much like our faith in questions of sense validity, the uniformity of nature, etc.).
3. Hence, because we cannot have knowledge of God’s existence or properties—because we are relegated to an epistemic realm preceding rationality and irrationality—we must accept that it is not in principle irrational to believe in the Christian God.