Buddhism taught no God, no Ruler of the universe, so gradually the masses brought their gods, and devils, and hobgoblins out again, and a tremendous hotchpotch was made of Buddhism in India. Again materialism came to the fore, taking the form of licence with the higher classes and superstition with the lower. Then Shankaracharya arose and once more revivified the Vedanta philosophy. He made it a rationalistic philosophy. In the Upanishads the arguments are often very obscure. By Buddha the moral side of the philosophy was laid stress upon, and by Shankaracharya, the intellectual side. He worked out, rationalised, and placed before men the wonderful coherent system of Advaita.