Buridan, Jean (c.1295–1358)
Jean Buridan was a French scholastic philosopher, Oxford contemporary of William of Ockham, and rector of the University of Paris. Buridan criticized the teachings of Aristotle and proposed the impetus theory, which is often considered to foreshadow Newton's first law of motion.
[It] must be realized that while another world than this is not possible naturally, this is possible simple speaking, since we hold from faith that just as God made this world, so he could have made several worlds.
Buridan was among those university intellectuals struggling to embrace Aristotelian doctrine with the teachings of the Christian Church. To this end, he suggested that God could, in principle, have created other worlds in each of which the four classical elements of earth, air, fire, and water, would have ordered themselves according to Aristotle's scheme. His ideas were taken further by Ockham and Nicole Oresme.