Guy Kahane asks an axiological question: what value would (or does) God’s existence bestow on the world? Supposing God’s existence is a matter of necessity, this axiological question faces a problem because answering it will require assessing the truth-value of counterpossibles. I argue that Kahane, Paul Moser, and Richard Davis and Paul Franks fail in their attempts to render the axiological question substantive. I then offer my own solution by bringing work in cognitive psychology and philosophy of mind to bear (...) on the possibility of assessing counterpossibles. I argue that humans can engage in counterpossible reasoning by “accepting” or “supposing” that the antecedent is true and “screening out” those beliefs that would result in contradictions when combined in inferences with the acceptance or supposition. These screened out propositions are not treated as false, but are ignored. I offer a three-valued logic for counterpossible reasoning. I conclude by outlining some implications for the axiological question. (shrink)