Analysing the story I find in it the following elements.
First, the medicine-king, or Theos, is afraid of his successor. In this case the possible successors are represented as his children. That may be a mere piece of convenience in story-telling; it may be the influence of a time when kingship was hereditary.
In all three cases the motive assigned by Hesiod seems to be the fear of a successor. The motive of Ouranos, indeed, is not very clearly stated. He began by hiding his children in the earth because they were ‘the most dangerous of sons’ (155). They ‘were hated of their father’, and ‘he rejoiced in the evil work’.
Kronos arose and conquered him: the exact meaning of the mutilation I leave aside. Kronos proceeded to swallow his children ‘intending that none other of the proud sons of Ouranos should have king’s rank among the immortals; for he had heard from Gaia and Ouranos that he was destined to be vanquished by his son’ (461 ff.). Here the motive is clearly given.
As for Zeus and his strange act in swallowing Metis when she was about to give birth to Athena, two quite distinct motives are attributed to him. First, that which we have met with before. ‘He was determined that none but himself should have the king’s rank, βασιληίδα τιμήν, over the immortals. He had heard an oracle that Metis was destined to give birth to’—one expects the motive of the Marriage of Thetis—‘a child who should be mightier than his father.’ But it is not quite so simple; for Athena was the child of Metis, and she was obviously not mightier than Zeus. The oracle takes the curious form that Metis is to bear ‘first Athena, and secondly a child who shall be mightier than his father.’ Zeus seems to have swallowed her rather prematurely. But he had a second motive also. He swallowed Metis ‘that the goddess being inside him should tell him of good and evil’. The name Μῆτις of course means ‘Counsel’ or ‘Wisdom’.
Leaving this last detail aside for the present, I suggest that the main motive in this strange story of the swallowing or hiding of the successive possible pretenders to the crown is the dread which each king naturally felt of him who was coming after. But this still leaves much unexplained; the second main element which I find is the worship of sacred flints or thunder-stones.
When Kronos set about swallowing Zeus, you will remember, Gaia put a big stone in swaddling clothes and gave it to great Kronos. And he ‘put it inside his belly’, ἑὴν ἑσκάτθετο νηδύν (487). Then, ‘in the passing of the years’—whatever that exactly means—‘beguiled by the counsels of Gaia, great crooked-hearted Kronos spewed up his brood again, being conquered by the craft and force of his son’. (Two reasons there, belonging probably to different stories—in one he was overcome by the craft of Gaia, in the other by the mana of his son.) ‘And the first thing he vomited up was the stone, which he had swallowed last.... Then straightway Zeus set loose his father’s brothers, the Titanes. They were grateful, and gave him three gifts, thunder and thunder-bolt and lightning; formerly vast Earth had hidden them away: and it is by them that Zeus rules over mortals and immortals.’[57]
That is to say Zeus in this story is a thunder-god. The thunder or lightning is his mana. And not only a thunder-god, he is a thunder-stone. The identity has been, of course, disguised in our present version of the myth. It is muddled, like everything else in Hesiod.[58] But it shows through. When Kronos sets about swallowing Zeus, it is the stone he swallows. And it is only when ‘by the counsels of Earth’ Cronos vomits up the stone that Zeus can take any action; and that action takes the form of thunder and lightning, the special property of a thunder-stone. In the word ‘thunder-stone’, or κεραυνία, the ancients seem to have mixed, and perhaps confused, two ideas: that of a meteorite, which seemed to be the actual bolt which fell in the thunder, and that of an ordinary flint, nephrite, jade, or the like, which has its mysterious fire inside it. The fire is the soul, or indwelling mana, of the flint.
A careful reading of Hesiod’s story will, I think, convince most anthropologists that Zeus is the stone. And as a matter of fact it is not uncommon for both Zeus and Jupiter to appear as stones. In the temple of Jupiter Feretrius, the oldest temple of Jupiter in Rome, founded by Romulus, there was a sacred flint which was called Jupiter Lapis—it was not Jovis Lapis. It was used for killing the victim in solemn treaties. It must have been one of those ‘thunder-stones resembling axes’ of which Pliny speaks; what we should call neolithic axe-heads. There seems to have been more than one Jupiter Lapis; for in 201 b.c. the Senate sent several such with the fetiales to Africa. I need not dwell on other cases; the Zeus Kappôtas at Gythîum, apparently a bigger stone, as Orestes could sit upon it; the Zeus Kasios or Keraunios at Seleucîa; the stone of Zeus Sthenios, on the road from Trozên to Hermione; or the thunder-stone on Mount Ida, in Crete, with which Pythagoras was purified by the Idaean Dactyls, the attendants of Zeus. They are all in De Visser’s book.
The best known of these stones is perhaps that which was believed to be—not to belong to, but actually to be—the Mother of the Gods. Livy (xxix. ii) tells of the embassy sent from Rome to Attalus to fetch the Great Mother; and how the king took the legates to Pessinûs in Phrygia and handed over to them the sacred stone which the natives affirmed to be the Mother of the Gods. Arnobius describes its appearance: ‘a stone not large, which could be carried in a man’s hand without noticeable weight, in colour black and furvus, in shape more or less round with projecting corners, which is now to be seen in the mouth of the image of the Great Mother.’ Superstitious Rome was ready to accept and to worship the Mother in the form of a stone; but common-sense Rome did at least demand that the Great Mother should have a decently anthropomorphic image, and the stone was then placed in the image’s mouth.