Philosophical aspects of cosmology

Abstract The development of cosmological theories has been accompanied by philosophical debates inspired by the contrasts between cosmology and other areas of physics. This chapter reviews aspects of these debates from a historical perspective, beginning with debates about whether the uniqueness of the universe implies that cosmology needs a distinctive methodology. Underdetermination of theory by the evidence is particularly challenging due to horizons and inaccessible physics. Theories of the ‘origin’ of the universe do not have the same structure as other physical theories. Recent debates have focused on how to evaluate theories that predict a multiverse, in particular regarding the significance of fine-tuning and how to conduct anthropic reasoning.