Porphyry states that all diviners attribute their predictions to gods or demons, but that he wonders if foreknowledge may not be a power of the human soul or perhaps accountable for by the sympathy which exists between different parts of the universe. Iamblichus holds, however, that divination is neither a human art nor the work of nature but of divine origin.[1404] He perhaps regards it as little more than a branch of theurgy. He distinguishes between human dreams which are sometimes true, sometimes false, and dreams and visions divinely sent.[1405] If one is able to predict the future by drinking water, it is because the water has been divinely illuminated.[1406] That we can predict when the mind is diseased and disordered, and that stupid or simple-minded men are often better able to prophesy than the wise and learned, are for him but further proofs that foreknowledge is a divine gift and not a human science, while divination by such means as rods, pebbles, grains of corn and wheat simply excites the more his pious admiration at the greatness of divine power.[1407] He disapproves of divination by standing on characters,[1408] but sees no reason why divination in darkness, in a wall, or in sunlight, or by potions and incantations, may not be divinely directed. He will not, however, connect the disordered imaginations excited by disease with divine presentiments.[1409] From true divination he also separates the “natural prescience” of certain animals whose acuteness of sense or occult sympathy with other parts and forces of nature enables them to perceive some coming events before men do. Their power resembles prophecy, “yet falls short of it in stability and truth.”[1410] Augury is an art whose conjectures have great probability, but they are based upon divine signs or portents effected in nature by the agency of demons.[1411] [Sidenote: Are the stars gods?] The stars are on a totally different plane from the other substances employed in divination. To Porphyry’s question whether they are not gods Iamblichus is not content to reply that the celestial divinities comprehend these heavenly bodies and that the bodies in no way impede “their intellectual and incorporeal perfection.”[1412] He must needs go on to argue that the stars themselves, as simple indivisible bodies, unchanging in quality and uniform in movement, closely approach to “the incorporeal essence of the gods.” He then triumphantly if illogically concludes, “Thus therefore the visible celestials are all of them gods and after a certain manner incorporeal.” We may add the opinion of Chaeremon and others, noted by Porphyry, that the only gods were the physical ones of the Egyptians and the planets, signs of the zodiac, decans, and horoscope; all religious myths were explained by Chaeremon as astrological allegories. [Sidenote: Is there an art of astrology?]