Miles K. Donahue

Expositions of the fine-tuning argument (FTA) typically aim only to show that cosmic fine-tuning is evidence for theism over specific versions of naturalism. But, construed as an argument for theism, that modest contention threatens the FTA with insignificance, as there may be other hypotheses that better explain fine-tuning than either theism or one's preferred formulation of naturalism. Adopting a Bayesian framework, I assess four such possibilities: the simulation hypothesis, teleological cosmopsychism, axiarchism, and teleological laws. I conclude that theism is superior to all four.

I discuss the multiverse response to arguments for theism from cosmological fine-tuning. In particular, I focus on the Hacking-White 'this universe objection', the contention that inference to a multiverse from fine-tuning commits the inverse gambler's fallacy. I conclude that specifically fine-tuning arguments for a multiverse do commit that fallacy and therefore fail, but I leave open whether other arguments--in particular, those that appeal to the existence of our universe or to self-locating evidence--succeed. I then argue that White's subsidiary claim, that if we know a multiverse exists independently from fine-tuning, then fine-tuning is no longer evidence for theism, is false. As such, even if a multiverse exists, the fine-tuning argument for theism can be refashioned in a multiverse context without any loss of force compared to a single-universe version thereof.

Several philosophers contend that a theistic multiverse (TM), a collective of all possible universes worthy of divine creation, is the best possible world, and that this fact proves helpful to theism in the face of various objections. Almeida (2017), however, argues that proposed theories of TM are incoherent. After presenting TM, I distinguish three objections Almeida raises against it: God cannot create universes corresponding to other possible worlds, we cannot know whether TM includes only worthwhile universes, and TM violates the principle of plenitude. I show that none of these undermine TM’s potential to address various objections to theism.

I examine the claim that theistic and scientific multiverses conflict: the former require that only universes above a certain threshold of value exist, while the latter make no such stipulations. I explore several avenues of reconciliation: appealing to ceteris peribus conditions ostensibly inherent within scientific theories, redefining `universe' in the philosophical context, advocating skeptical theism, contending that God and gratuitous evil are compatible, and adjusting the relevant scientific theories. I conclude that only the last strategy is viable, as long as we grant the coherence of a Molinist account of divine providence. If successful, it would entail that scientific and theistic models conflict only superficially. If not, however, then the theistic multiverse is inconsistent with its scientific counterparts.

After outlining sceptical theism (ST) and the fine-tuning argument (FTA), I demonstrate how arguments for the former undercut the latter. I then consider and reject three recent proposals for ameliorating the conflict: positive ST, considerations about normative superiors, and appeal to theistic metaethics. I contend, however, that Kirk Durston’s complexity argument for ST does not undercut the FTA but in fact supports it. In defending that thesis, I respond to Climenhaga’s contention that ST undermines all warrant for theistic belief, the FTA included.

After briefly outlining the fine-tuning argument (FTA), I explain how it relies crucially on the claim that it is not improbable that God would design a fine-tuned universe. Against this premise stands the divine psychology objection: the contention that the probability that God would design a fine-tuned universe is inscrutable. I explore three strategies for meeting this objection: (i) denying that the FTA requires any claims about divine psychology in the first place, (ii) defining the motivation and intention to design a fine-tuned universe into the theistic hypothesis, and (iii) providing arguments that the relevant probability is not terribly low. While I reject the first two, I conclude, in line with the third, that considerations about life's objective value establish that it is not absurdly improbable that God would design a fine-tuned universe, whether one regards the FTA as an inference merely to a cosmic designer, or to theism proper. Accordingly, the divine psychology objection fails.

I present and evaluate three interpretations of methodological naturalism (MN), the principle that scientific explanations may only appeal to natural phenomena: as an essential feature of science, as a provisional guideline grounded in the historical failure of supernatural hypotheses, and as a synthesis of these two approaches. In doing so, I provide both a synoptic overview of current scholarship on MN, as well a contribution to that discussion by arguing in favor of a restricted version of MN, placing it on a firmer theoretical foundation than that supplied by previous studies, and replying to recent objections.