God as Best Explanation of the Universe

The strongest positive case for God as the best explanation comes from Aquinas' reasoning about contingency, Leibniz's principle of sufficient reason, and Swinburne's fine-tuning argument, but Hume and Russell raise difficulties that prevent this case from being conclusive.

Aquinas' Third Way argues that contingent beings — those that could fail to exist — cannot explain their own existence; if everything were contingent, there would be nothing at all, so there must be a necessary being whose existence is self-explanatory. Leibniz reinforces this: there must be a sufficient reason for why there is something rather than nothing, and only a self-subsistent God provides that reason. Swinburne adds the fine-tuning dimension: the physical constants of the universe (gravity, the strong nuclear force, the cosmological constant) are calibrated to extraordinary precision to permit the existence of life and complexity. On Swinburne's inference-to-the-best-explanation method, God — as a single, simple, omnipotent mind — is the most parsimonious explanation of this fine-tuning, requiring fewer assumptions than positing many universes or pure chance.

Hume and Russell challenge each step. Hume argues that the principle of causation — on which Aquinas and Leibniz rely — is merely a habit of mind, not a necessary feature of reality. We never perceive necessary connections, only constant conjunctions; the universe might simply exist as a brute fact without requiring an explanation. Russell puts it bluntly: "The universe is just there, and that's all" — there is no obligation to explain its existence any further. Regarding fine-tuning, the multiverse hypothesis — the idea that a vast or infinite number of universes exist with varying physical constants, making at least one hospitable to life statistically inevitable — provides a non-theistic alternative that removes the apparent improbability of our universe.

Defenders of God as best explanation can respond that Russell's "brute fact" is not really an explanation at all — it simply stops inquiry at an arbitrary point. Copleston argues that we should seek a total explanation, not just the explanation of parts. A multiverse, moreover, faces its own explanatory challenge: what generates the multiverse, and why do the laws governing it take the form they do? If the multiverse requires its own explanation, theism — positing a necessary being who explains both the universe and the laws — may still be simpler overall.

This exchange shows that neither side has a decisive advantage. Theism offers a unified, intentional explanation for why there is something rather than nothing and why it is ordered for life; this is genuinely attractive as an explanatory hypothesis. However, the multiverse and brute-fact responses show that non-theistic alternatives are not obviously worse, and positing an infinite, omnipotent mind is not obviously simpler than positing natural laws. Swinburne's inference-to-best-explanation depends on prior probability judgements about simplicity that not everyone will share. The theistic case is therefore a live and serious explanation, but not demonstrably the best.

So, while God provides a plausible answer to questions of ultimate origin and fine-tuning, the availability of coherent alternatives prevents theism from being conclusively identified as the best explanation at this level.

Even granting that some explanation is required for the universe, alternative naturalistic explanations and the problem of evil cast doubt on whether the God of classical theism is specifically the best candidate.

Darwin's theory of evolution by natural selection provides a powerful non-theistic explanation for biological complexity and apparent design in living things, removing one of the most compelling historical reasons for believing in a designer. Dawkins extends this into a broader metaphysical claim: the success of evolutionary biology suggests that blind physical processes can generate extreme complexity without any directing intelligence, making God an unnecessary hypothesis for the features of the world we observe. More fundamentally, the problem of evil challenges the claim that God is specifically the best explanation: if God is omnipotent, omniscient and omnibenevolent, the quantity and distribution of natural evil (earthquakes, disease, tsunamis) and moral evil in the universe is very difficult to explain. An omnipotent, all-loving designer would presumably have created differently; the universe as it is looks more like what we would expect from a blind, indifferent process than from a loving God.

However, these alternatives have their own weaknesses. Evolution explains biological complexity but not the origin of the universe itself, nor the existence of the laws of nature that make evolution possible; Dawkins' argument therefore shifts the explanatory gap rather than closing it. The problem of evil is a challenge to classical theism specifically, but not to every version of the theistic hypothesis; defenders like Alvin Plantinga and John Hick argue that a world with morally significant free creatures or soul-making opportunities is better than a world of perfectly comfortable automatons, and that God might have sufficient reasons for permitting evil that we cannot fully grasp.

Dawkins and Hume can respond that any version of God capable of being the best explanation must include the traditional attributes (omnipotence, omniscience, omnibenevolence) to do the explanatory work required; a limited or indifferent deity fails to explain the universe's order and suitability for life. And a perfectly powerful, all-loving God remains deeply at odds with a world containing the Holocaust, childhood cancer and mass extinctions. The "soul-making" defence asks us to accept enormous amounts of suffering on the basis of speculative claims about God's inscrutable purposes — which is not the kind of transparent best explanation we would accept in any other domain of inquiry.

On balance, these naturalistic challenges significantly weaken the claim that God is the best explanation when we attend to the full range of evidence — not just the universe's existence and fine-tuning, but its actual content, including its massive amounts of suffering and waste. A truly best explanation should account for all the evidence, and theism struggles significantly with evil and suffering. The naturalistic alternative — that blind physical processes account for complexity, and that suffering simply has no ultimate justification — is less satisfying existentially but arguably more honest to the totality of evidence.

Thus, once we move beyond the bare existence and fine-tuning of the universe and consider its actual character — including evil, waste and indifference — the case for God as the best explanation weakens considerably, and naturalistic alternatives become more competitive.