In modern times, cosmology has become one of the most epistemically fertile fields of science. Some of its successes are: addressing the Cosmic Microwave Background and its features (temperature, anisotropies, polarization, etc.); accounting for the chemical elements abundances in the universe; the discovery of the isotropic expansion of the universe; the establishment of a model which synthesizes various observations (SNIFS, BOSS, COBE, etc.) into a relativistic model (of on overall flat geometry) with predictive power; and much more. In spite of this, there are still some philosophical issues concerning not only cosmology as a science of the universe (Ellis, 2001), but also about the complex interactions between theory and evidence (Smeenk, 2017), and the status of theoretical entities whose evidence has been persistently indirect (Martens, 2022).
The role and status of different kinds of evidence in cosmology. (What counts as evidence in cosmology? How do models, simulations, and observations interact in cosmological practice?)
Testability and evaluativeness of cosmological theories (How should we evaluate theories that are only indirectly testable?)
The status of cosmological entities (What is the status of cosmological entities (such as the multiverse, dark matter, or dark energy)?
Formal approaches to reasoning in cosmology (have alternative logics any use in cosmology?, are cosmological phenomena fully consistent?)
The status of cosmology as a science (What role does cosmology play in shaping our conception of science, knowledge, and the universe as a whole?)