Volcanic flows of fantasy

In the 19th century, theories of myth took the subject of myth to be the physical world and the function of myth to be the explanation of events in the world. Myth was considered the "primitive" counterpart to natural science, which was deemed exclusively modern. Myth and science did not merely duplicate but contradicted each other. Because moderns by definition espouse science, they had to reject myth. By contrast, 20th-century theories took myth to be about anything but the physical world. Myth could be about the social world, about the world to come, or about the mind. Similarly, the function of myth could be expressive, justificatory or compensatory - anything but explanatory. Myth and science were now compatible.

When They Severed Earth from Sky is a throwback to a 19th-century approach. Myth is, if not quite an explanation of the physical world, a way to relay information about it. The description is accurate, so myth is itself scientific. Elizabeth and Paul Barber focus on a myth of the Klamath tribe of Oregon about a cosmic battle between gods. The authors correlate the battle with a volcanic eruption. Since Crater Lake was formed by ashes from an eruption 7,700 years ago and since the Klamath Indians know of this event and remain wary of the lake, they must have garnered their information from the myth. So we are told.

But why should the record of an eruption take the form of a battle between gods? The Barbers offer scores of "myth principles" to account for this.

For example, the redundancy strategy: "Because of the importance attached, particular information will tend to be encoded with a high degree of redundancy and/ or vividness." Oral societies must find ways to ensure the survival of key information. Hence the myth describes variously the reign of fire and vividly two men's willingness to jump into lava to save the world.

Others have argued the same as the Barbers. In Hamlet's Mill , Giorgio de Santillana and Hertha von Dechend show that astronomical calculations underlie various myths. In Natural Knowledge in Preclassical Antiquity , Mott Greene correlates the divine war in Hesiod's Theogony with a volcanic eruption. The Barbers go further to try to explain why natural processes should become gods. For them, myths merely record, not explain, observations. They therefore concoct endless principles to explain why events are not just passed on as observations. But the question remains: why transform observations into far more complex stories?

To support their analysis, the Barbers enlist Henri and H. A. Frankfort's Before Philosophy . But the Frankforts maintain that our forebears lived in a mythopoeic haze oblivious of everyday observations - the opposite of the Barbers' position. The Barbers fall in the camp of those who root myth in reality. The opposing camp roots it in imagination. The Barbers sidestep rather than confront their nemeses, who are prepared to show that myths about gods are, for example, projections of humans' behaviour. The Barbers must spurn the role of fantasy to retain their 19th-century view.

Robert Segal is professor of theories of religion, Lancaster University.