Abstract

Proponents of the this-universe objection to fine-tuning arguments for a multiverse claim that while the multiverse hypothesis raises the probability that some universe is fine-tuned for life, it fails to raise the probability that this one is. Because that is so, they further argue, those who take the fine-tuning of this universe as evidence for the multiverse hypothesis are guilty of a probabilistic fallacy. I argue that a proper evaluation of the this-universe objection requires the development of a general, formal framework for reasoning probabilistically with evidence statements expressed using indexical terms (such as the statement [This universe is fine-tuned]). I proceed to develop such a framework and then to apply it to the this-universe objection. While my primary aim is to defend the this-universe objection from recent rebuttals, a secondary aim is to exhibit the utility of the framework itself, which has the potential for wider application.