CAMPBELL: The serpent, who dies and is resurrected, shedding its skin and renewing its life, is the lord of the central tree, where time and etemity come together. He is the primary god, actually, in the Garden of Eden. Yahweh, the one who walks there in the cool of the evening, is just a visitor. The Garden is the serpent’s place. It is an old, old story. We have Sumerian seals from as early as 3500 B.C. showing the serpent and the tree and the goddess, with the goddess giving the fruit of life to a visiting male. The old mythology of the goddess is right there.
MOYERS: But how do you explain the difference between that image and the image of the snake in Genesis?
CAMPBELL: There is actually a historical explanation based on the coming of the Hebrews into Canaan and their subjugation of the people of Canaan. The principal divinity of the people of Canaan was the Goddess, and associated with the Goddess is the serpent. This is the symbol of the mystery of life. The male-god-oriented group rejected it. In other words, there is a historical rejection of the Mother Goddess implied in the story of the Garden of Eden. 
- Campbell, Joseph. The Power of Myth. Anchor,1988. 54. [↩]