The need for pushers ended when Jean Buriden (1300–58), rector of the University of Paris, anticipated Newton’s First Law of Motion by proposing that space is a vacuum, and that once God had put the heavenly bodies in motion (“impressed an impetus on each”), their motion was “not decreased or corrupted afterwards because there was not inclination of the celestial bodies for other movements. Nor was there resistance which could be corruptive or repressive of that impetus.”
