Abstract

The finitude or infinity of the universe divided the ancient philosophers fueling a debate intertwined with the subtleties of the very concept of infinity and the plausibility of its realization in the physical world. While the 19th century took the first steps in the formal domain of mathematical infinity, the question of the size of the cosmos remained open pending better empirical evidence. At the end of the 20th century, the observational data of cosmology seemed to favour an infinite volume, although the delicate physical and metaphysical problems that such an option implies have rarely been highlighted.