I’m standing in a basement kitchen prodding at a sheep’s liver, looking for marks on its smooth surface. People crowd around to film the proceedings, since I’m here to ask a question that everyone wants to know the answer to: will Donald Trump win the US election?

I’m following instructions that were first written down by the ancient Babylonians 4,000 years ago, and still survive today. Every crease on the liver has a meaning, and cuneiform tablets discovered in modern-day Iraq explain how to interpret them.

Armed with this knowledge, it’s possible to calculate the answer to any question, so long as it is yes or no, by adding up the number of positive or negative signs and seeing which comes out on top.

Since this liver had an overwhelming number of bad omens in it, I concluded that it declared no for Trump this time. Though in 2016 this method predicted a win well before he had won the Republican nomination, and in 2020 foretold that he would not be reelected that year.

What started as an entertaining talk for a university open day has since become a serious part of my research – not because I sincerely believe in it, but because it gives us some of the earliest evidence in history for how human beings reason and think.

Looking at livers also makes a serious underlying point about how humans have coped with uncertainty throughout history, and still struggle to today. People have developed techniques as varied as astrology, tarot cards and even peering into entrails in response to the agony of not knowing, or the strain of trying to make a difficult decision.

Given the level of feeling invested in this election, it’s a unique moment where perhaps we can appreciate that, in this respect, we are not so different from those who lived thousands of years ago, even if our methods of looking into the future are different.

Asking the entrails

Developed in its classic form in Babylon, entrail divination was practised throughout ancient Mesopotamia, the written history of which spans from the 3rd millennium BC to the 1st century AD.

It was enormously important in all sections of society – a standard part of political decision-making at the royal court, but accessible to all. Budget options were even available for those who could not afford a sheep.

People addressed their questions directly to the gods and believed that at the moment of asking, the answer would be written on the entrails. This could then be “read” by a diviner trained in this esoteric language.

Sitting in the British Museum is an archive of real questions that were asked by the king of Assyria (a kingdom in northern Mesopotamia) in the 7th century BC. All kinds of affairs of state were put before the gods. Are the Egyptians going to attack? Has the enemy taken the town under siege? And will the governors return home safely?

Reading the archive, you get a real sense of nerves on a knife-edge as the king waited for news from far away, wanting to know what had happened to his troops and trying to decide what to do next.

Not only did he ask them about what would happen in the future, but he also consulted them on possible courses of action. Should the Assyrian army go to war? Should the king send a messenger to make peace? Asking the opinion of the gods would have helped him feel more confident in his next steps.

The Babylonians did not have elections. But that did not mean the king could do whatever he wanted. It was important for his public image to have the gods onside, as well as for his own reassurance.

Whenever a powerful official was appointed, the entrails would be read to ensure the gods approved. The head of the army, high priests and other important positions were all subject to this requirement. On one occasion, even the choice of crown prince – and hence the future king of Assyria – was put to this test.

Interpreting the entrails was held to almost scientific standards of exactitude. Diviners worked in pairs or groups of up to 11, checking each other’s work to make sure they got it right. This was not a vague or woolly process, but a real attempt to ensure “accuracy” that could not be manipulated to simply come up with the answer that the king wanted to hear.

Modern forecasting

We all want to know what the future has in store, and have come up with ingenious ways of trying to find out, from opinion polls and data modelling to Paul the octopus, who developed a reputation for picking the winners of football matches during the 2010 World Cup. But are our methods really any better than looking inside a sheep?

As all investors are warned, past performance does not guarantee future results. Yet the only data we have to inform our predictions comes from the past, and most of our models can’t take into account “unknown unknowns”.

As many experts have found, predicting the future is a difficult business: opinion polls can lie and people change their minds, while economists have often been blindsided by a sudden crash.

Since liver divination only answers “yes” or “no”, it is going to be right 50% of the time just through the law of averages. Despite its randomness, its success rate may well have seemed convincing at the time.

And when we trust the authority of the source, it’s easy to find a way to explain away a wrong result – the prediction got halfway there, answered a different question, or would have been right if x hadn’t happened.

We shouldn’t be blind to the weaknesses of our own methods. We are often wrong, and the Babylonians could sometimes be right.