Cosmology (the study of the physical universe) is a science that, due to both theoretical and observational developments, has made enormous strides in the past 100 years. It began as a branch of theoretical physics through Einstein’s 1917 static model of the universe (Einstein 1917) and was developed in its early days, particularly through the work of Lemaître (1927).[1] As recently as 1960, cosmology was widely regarded as a branch of philosophy. It has transitioned to an extremely active area of mainstream physics and astronomy, particularly due to the application to the early universe of atomic and nuclear physics, on the one hand, and to a flood of data coming in from telescopes operating across the entire electromagnetic spectrum on the other. However, two main issues make the philosophy of cosmology unlike that of any other science.
