Testability and Viability: Is Inflationary Cosmology “Scientific”?

We provide a philosophical reconstruction and analysis of the debate on the scientific status of cosmic inflation that has played out in recent years. In a series of critical papers, Ijjas et al. have questioned the scientificality of the current views on cosmic inflation. Proponents of cosmic inflation have in turn defended the scientific credentials of their approach. We argue that, while this defense, narrowly construed, is successful against Ijjas et al., the latter's reasoning does point to a significant epistemic issue that arises with respect to inflation. A broadening of the concept of theory assessment is needed to address that issue in an adequate way.