Finally, there is another theory which, like the ancestor hypothesis, seeks to derive gods, or at least the beings generally regarded as gods, from more primitive mythological ideas. This theory, which was developed by Hermann Usener, the most prominent student of the science of religion among recent classical philologists, might perhaps be referred to, in distinction from the soul and ancestor hypothesis, as the _demon theory_ of the origin of gods. Usener agrees with the rival hypothesis in assuming that the exalted celestial deities were not the first of the higher beings who were feared or worshipped in a cult, but that there were other more temporary gods. Though these many temporary gods are described as demoniacal beings, they are nevertheless regarded as gods of a primitive sort. Usener distinguishes three stages in the development of gods. First, there was the 'god of the moment.' Some phenomenon--such, for example, as a flash of lightning or a clap of thunder--was felt to be divine. But, inasmuch as the impression was vanishing, the mythological idea in question was that of a 'god of the moment.' Then followed a second stage, in which a demoniacal power was associated with a particular place. Following upon these local gods came other gods, representing the guardian powers of a tribe, a vocation, or some other social group. At the third stage of development, the 'particular god' acquired a personal nature, and thus finally became a god proper. The gods of this final stage are called by Usener 'personal gods.'