title: The Fatal Consequences of a Priori in the Natural Sciences, to be Replaced by Facts
abstract: Let us first speak, in Astronomy, of the original conception of the Universe, based on appearances. Every man, sailing on the sea, far from the coast, in good weather, sees the sky horizontally, in all directions, and vertically. He speaks of "celestial vault, '' an apparent sphere on which, by clear night, moves, together with the stars "carried" by it. That was what was described by Aristotle in his "De Coelo". Four centuries later, the astronomer Claude Ptolme, in his work "L'Almageste", repo