Some paradoxes emerging when the universe is thought of in terms of objectivity are considered in this article, in the light of the philosophy of L. Polo. Current metaphysical speculations on the basis of mo-dern cosmology cannot easily avoid this risk. The author examines in particular the problem of the beginning of time, with a confrontation between Polo and Aquinas. It is argued that cosmological thought must be carefully controlled in order to be referred to a metaphysical pers-pective