Divination was the guiding principle of life in ancient times. People would barely step outside the house without first consulting the will of the gods. They wouldn't get married, go on a journey or declare war without performing acts of divination. But now science is showing that at least some of this apparently superstitious behaviour had a rational . basis, writes Robert Temple.

One of the ancient specialities was interpreting bird behaviour to indicate changes in the weather. We now know that birds can hear infrasounds - sounds below the level of human hearing - from storm fronts hundreds of miles away. By observing the birds' behaviour, people were able to predict coming storms.
Similarly, the Roman author on architecture, Vitruvius, gave instructions on how to choose the location for a city. He suggested grazing animals be let loose on the site, then slaughtered and their entrails examined. If signs of disease were found, a new site should be sought. Today we call this technique an autopsy and it would indeed have revealed the presence of poisoned water supplies or dangerous plants that could have been fatal to a new settlement.

Recently conclusive evidence has been found that the sibyl of Delphi in Greece presided near a chasm that emitted ethylene gas, which sent her into a trance from which she produced her prophecies. Occasionally she would get an overdose of the gas, and the writer Plutarch, a high priest of Delphi in the lst/2nd centuries AD, records that one sibyl died of it. The trances of the Delphic sibyl ,were long thought to be simulated or imagined, but science has revealed their real origin.

Last year I was able to examine the Oracle of the Dead in Baia, an early Greek colony on the western coast of Italy. The Oracle of the Dead was a replica of the legendary Hades of the Greeks, complete with an artificial underground River Styx 150ft long.

This was the place where Odysseus in the Odyssey and Aeneas in the Aeneid "descended into hell" to consult the spirits of the dead. The Romans sealed the site 2,000 years ago and it was forgotten. Scholars had always assumed the visits to Hades were a myth, but like the "legendary" site of Troy discovered in the 19th century, it has turned out to be a real place.

So many of the so-called fantasies of the ancients have turned out to be based on fact that perhaps we should re-examine our attitudes. Understanding our ancestors with more objectivity can help us better understand ourselves.

Another remarkable confirmation of ancient observations relates to the portents ascribed to comets. The ancients maintained that these brought plagues and pestilence. In 1977 the late Sir Fred Hoyle, one of Britain's leading astronomers, and his collaborator Chandra Wickramasinghe published their theory that comets were dirty snowballs carrying bacteria and viruses that were strewn over Earth when the comets passed close enough, occasionally creating plagues.

At first this theory was derided by most astronomers, but recent evidence favours it, and confirmation appears to have occurred last summer when high-altitude balloons encountered large colonies of bacteria living 25 miles above the surface of the Earth, which apparently could only have been seeded by passing comets. Another example of the ancients being right after all.