Symbolism, Imagery, Allegory
Campbell is fascinated by people who seek power—both the kind of do-gooders who belt out "I've Got the Power" when they're on the top of their game, and bad baddies who want nothing more than a very starched suit and a white cat to stroke while pondering the downfall of their enemies. Because Campbell knows that power is as good or bad as the people who possess it.
Evil arises when people misuse it, like King Minos of Crete does:
Society has blamed the queen greatly; but the king was not unconscious of his own share of guilt. The bull in question had been sent by the god Poseidon, long ago, when Minos was contending with his brothers for the throne. Minos had asserted that the throne was his, by divine right, and had prayed the god to send up a bull out of the sea, as a sign; and he had sealed the prayer with a vow to sacrifice the animal immediately, as an offering and symbol of service. (12.2)
That kind of power becomes misdirected, and creates monsters, f horrible things that the hero has to stop. In order to do that, he needs to quest and reach the World Navel, where power can be granted by the goddess or wrested from a father figure, but which—in a surprise twist right out of an inspirational TED talk—may actually lie within the hero the whole time.
We and that protecting father are one. This is the redeeming insight. That protecting father is every man we meet. And so it must be known that, though this ignorant, limited, self-defending, suffering body may regard itself as threatened by some other—the enemy—that one too is
the God. (148.2)
Power can take on all kinds of forms: a magic ring, a lightsaber, or those various antique goodies that Indian Jones goes after. But in the end, it's just a stand-in for either the corrupting power that makes everything do wrong, or the healing power that sets it all right again.
The hero has to go out and find it…and the finding is what gives him the power: not to grab like a kid taking the TV remote away, but to understand that that symbol is just a way of understanding where real power lies.
It can take quite a bit to wrap your head around it. But when you do…whoa.