Religions have always existed as people seek an explanation for the unexplainable. A clerical hierarchy will rise up in every society as surely as entrepreneurs or other classes who claim to know the "truth", but, being unknowable, their truths are all pure dogma. Dogma is a very dangerous thing as there is no basis in fact so people resort to any means to convince others that their dogmas are the only real truth, making all others false by definition. More wars have been fought over religion than any other cause. It might even be argued all wars were.