But suppose two things to exist, then there must necessarily be an interval between those two--something separating and limiting them. What is that something? It is some _other_ thing. But then if not the _same_ thing, _it also_ must be separated and limited, and so on _ad infinitum_. Thus only one thing can exist as the substratum for all manifold appearances." Zeno furnishes us with an illustration of the fallibility of the indications of sense in his argument against Protagoras. It may be here introduced as a specimen of his method: "He asked if a grain of corn, or the ten thousandth part of a grain, would, when it fell to the ground, make a noise. Being answered in the negative, he further asked whether, then, would a measure of corn. This being necessarily affirmed, he then demanded whether the measure was not in some determinate ratio to the single grain; as this could not be denied, he was able to conclude, either, then, the bushel of corn makes no noise on falling, or else the very smallest portion of a grain does the same." [Sidenote: and by Melissus of Samos.] To the names already given as belonging to the Eleatic school may be added that of Melissus of Samos, who also founded his argument on the nature of Being, deducing its unity, unchangeability, and indivisibility. He denied, like the rest of his school, all change and motion, regarding them as mere illusions of the senses. From the indivisibility of being he inferred its incorporeality, and therefore denied all bodily existence. [Sidenote: Biography of Empedocles.] The list of Eleatic philosophers is doubtfully closed by the name of Empedocles of Agrigentum, who in legend almost rivals Pythagoras. In the East he learned medicine and magic, the art of working miracles, of producing rain and wind. He decked himself in priestly garments, a golden girdle, and a crown, proclaiming himself to be a god. It is said by some that he never died, but ascended to the skies in the midst of a supernatural glory. By some it is related that he leaped into the crater of Etna, that, the manner of his death being unknown, he might still continue to pass for a god--an expectation disappointed by an eruption which cast out one of his brazen sandals. [Sidenote: He mingles mysticism with philosophy.]