Dirac’s “fine-tuning problem”: A constructive use of anachronism?

Abstract

In order to shed light on contemporary arguments about "fine-tuning" in cosmology, I examine a possible historical precedent for fine-tuning from the early years of Quantum Electrodynamics: the divergent self-energy of the electron in Dirac's theory. I argue that viewing this problem as a fine-tuning problem involves an anachronistic reconstruction, but that such reconstructions can be philosophically useful so long as they are not confused with real historical understanding. I relate how, historically, this problem really was conceived, and show how one important step toward its solution drew upon an interpretation of Dirac's formalism in terms of "hole theory." In light of the subsequent demise of hole theory, I argue that my anachronistic reconstruction can serve as a cautionary tale that should considerably weaken the conclusions that might otherwise be drawn from attempts to give theistic or multiverse solutions to cosmological fine-tuning problems.