Putting the big bang in its historical perspective makes it appear as the result of a succession of random thinking, animated by new observations – although constrained by their reference frame – and that of concepts often frozen. It appeared first as the only solution able to account for the existing observations; with newer observations, it appears now just like the old Ptolemaïc system, to which Aristotelians, Platonians or Pythagorean of the Renaissance worked hard to add epicycles, and again new epicycles, against all the principles of simplicity claimed in their beginnings, in order to save the basic principles of the model.