[HerbManic]

One of the stranger theories I have seen is that it is based on Astrology as there is a confluence of Uranus squaring the lunar nodes... whatever that means. There is a saying supposedly attributed to JP Morgan (but not likely) "Millionaires don't use astrology but Billionaires do."

One of the more rational ideas I have seen of any kind of divination is that it provides a means of passing judgement over to a near seemingly random system. If you are reading tea leaves, doing an 'I Ching' divination, biobliomancy etc. that essentially provides a coin flip to make you go 'yes' or 'no' to an opportunity.

[science4sail]

Indeed, there are several anthropological works speculating that the purpose of divination is to break analysis paralysis or unconscious biases.

And if you are already sure of the correct solution, then you can just keep doing the divination over and over again until the gods give the answers that you want!