In the first place, it is plain that Plato had a firm religious and philosophical faith in the immortality of the soul, which was continually attracting his thoughts, making it a favorite theme with him and exerting no faint influence on his life. This faith rested both on ancient traditions, to which he frequently refers with invariable reverence, and on metaphysical reasonings, which he over and over presents in forms of conscientious elaboration. There are two tests of his sincerity of faith: first, that he always treats the subject with profound seriousness; secondly, that he always uses it as a practical motive. "I do not think," said Socrates, "that any one who should now hear us, even though he were a comic poet, would say that I am talking idly."16 Again, referring to Homer's description of the judgments in Hades, he says, "I, therefore, Callicles, am persuaded by these accounts, and consider how I may exhibit my soul before the judge in the most healthy condition."17 "To a base man no man nor god is a friend on earth while living, nor under it when dead," say the souls of their ancestors to the living; "but live honorably, and when your destined fate brings you below you shall come to us as friends to friends."18 "We are plants, not of earth, but of heaven."19 We start, then, with the affirmation that Plato honestly and cordially believed in a future life. Secondly, his ethical and spiritual beliefs, like those of nearly all the ancients, were closely interwoven with physical theories and local relations. The world to him consisted of two parts, the celestial region of ideas, and the mundane region of material phenomena, corresponding pretty well, as Lewes suggests, to our modern conception of heaven and earth. Near the close of the Phado, Socrates says that the earth is not of the kind and magnitude usually supposed. "We dwell in a decayed and corroded, muddy and filthy region in the sediment and hollows of the earth, and imagine that we inhabit its upper parts; just as if one dwelling in the bottom of the sea should think that he dwelt on the sea, and, beholding the sun through the water, should imagine that the sea was the heavens. So, if we could fly up to the summit of the air as fishes emerging from the sea to behold what is on the earth here and emerge hence, we should know that the true earth is there. The people there dwell with the gods, and see things as they really are; and what the sea is to us the air is to them, and what the air is to us the ether is to them." Again, in the tenth book of the Republic, eleventh chapter, the soul is metaphorically said in the sea of this corporeal life to get stones and shell fish attached to it, and, fed on earth, to be rendered to a great extent earthy, stony, and savage, like the marine Glaucus, some parts of whose body were broken off and others worn away by the waves, while such quantities of shells, sea weed, and stones had grown to him that he more resembled a beast than a man.