Assessing fine-tuning of cosmic inflation
I clarify and philosophically interpret a high-stakes dispute in cosmology about the bedrock of our understanding of the very early universe---that is, about the theory of cosmic inflation. I identify three core charges against cosmic inflation: (i) it is too permissive, (ii) it gives rise to a multiverse with associated problems of confirmation and (iii) it is finely tuned. I argue that we are, today, in a position to assess only the third charge, and thus to assess whether inflation faces a fine-tuning problem analogous to the one it was designed to solve. I then present a detailed account of how to evaluate the fine-tuning of inflation from a thoroughly modern perspective, together with recent results from an implementation of such an account.