ABSTRACT
In Ephemerides novae he urged astronomers to begin with celestial observations instead of intellectual or abstract speculations. Bruno distinguishes the infinite sphere of the world from the finite spheres of celestial bodies. According to him not only is the universe infinite, but it also includes innumerable worlds, or better, heliocentric planetary systems. This viewpoint was shared by Kepler and Benedetti, though they were in disagreement as to the degree of mathematical perfection of the material world. In the late Renaissance, as we have seen, the most influential post-Copernican astronomers founded their views on metaphysical speculations about the perfection of the universe, though differently conceived. Besides, their disagreement on cosmology, perfection of the world and mathematics reveals that, between the sixteenth and the seventeenth centuries, there was no standard Copernicanism, despite the simplified image, later promoted by Galilei, of a struggle between two chief world systems, Copernican and Ptolemaic.
