... vents in the heavens. By using this single supposition, he was able to explain phenomena such as eclipses by a single occurrence: the blockage of heavenly vents. He can be considered the first metaphysician because he rationalized and hypothesized about the Aperion as the Arche. Unlike Thales, Anaximander speculated that the Aperion differed from the elementals and reasoned instead that since it was the fundamental source of all things and surrounded the heavens and worlds, it could not be any one of those things or possess their characteristics. This is why the earth does not move in space, because the Aperion has an "equal relation to the extremes" and there is no reason for it to move. According to Anaximander, the Aperion must be spatially unlimited because it environs the universe. As an unlimited material, if the Aperion possessed a definite set of characteristics, it would obliterate everything with opposing characteristics. ...

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