Yuval Noah Harari should be on top of the world. He has achieved a success few writers ever manage. He has sold more than 45 million books in 65 languages.¹ He has been feted by public figures including Barack Obama and Bill Gates. And he is about to embark on an international tour in support of his new release Nexus.

Yet Harari is glum. In the last decade, he thinks, the world has been "downhill on all fronts".

Nexus claims, among other things, that "humanity is closer than ever to annihilating itself".

Harari writes from a unique perspective. He trained as a medieval historian. But his books mix millennia-spanning history with ideas from philosophy, science, economics and law. 

His big break came with Sapiens (2011), which argued that homo sapiens became the world's dominant species because of our ability to coordinate and work together. He thinks we gain this power through using our imagination. Through it, we created concepts like money and religion, as well as biasBiases are beliefs that systematically and unfairly distort a person's decisions, in favour or against one group or another. and prejudiceAn idea about something, especially a group of people, that is not based on reality. . 

Sapiens spent 182 weeks on The New York Times bestseller list. He followed it up with Homo Deus (2015), which explored possible futures for humanity, and a collection of essays called 21 Lessons for the 21st Century (2018). 

Nexus is expected to be another huge hit. Its topic is information networks and how they shape our world. But it takes in almost everything else, from the birth of printing to QAnonFollowers of QAnon believe a Satanic conspiracy removed President Trump from office. . The Times says: "The scope is terribly cosmicRelating to the universe or cosmos.."

Harari asserts that we are on the brink of an existential crisis. Nations are wracked by plague and war. DemocracyA system of government based on the idea of rule by the people. is foundering. Climate change is causing floods, famines and fires.

He is especially worried that technology will render humanity obsolete. Although AIA computer programme that has been designed to think.  is developed by humans, he considers it an "alien intelligence".

Harari says: "If we mishandle it, AI might extinguish not only the human dominion on Earth but the light of consciousness itself, turning the universe into a realm of utter darkness."

We know that AI poses a risk. Yet companies and governments cannot stop researching it - in part because they are scared someone else might get their first.

The potential dangers of this AI explosion are many. AIs could replace jobs and make millions unemployed. AI-generated fake words and pictures could distort our sense of reality. And AI could one day become more intelligent than us - and decide to take over.

Yet some think that Harari is too pessimistic. He assumes that AI can easily beat us. He imagines that a bot could pose as a person and seduce us or steal our information. But humans are not passive. If AI starts to threaten us, we will find a way to win.

Others criticise his method. He looks at the big picture but often misses the details. He blames the fall of the Roman Republic, for instance, on flawed information networks. A specialist might argue that other, more specific factors played a role. He also, Corbin Barthold writes "tends to assume that trends continue indefinitely".

Is Yuval Noah Harari right?

Yes: The last few years have seen the world take a dark turn. And it seems to be getting darker. Harari's view is terrifyingly bleak. But it is difficult to imagine all his problems being solved.

No: Many humans have tried to predict how and why the world would end. NostradamusA 16-century French astrologer and physician whose prophecies earned him fame both during and after his lifetime. These included being credited with predicting the rise of Adolf Hitler, the atomic bomb and the Kennedy Assassination.  thought it would happen in 1999. RasputinA Russian mystic who gained considerable influence over the last Tsar, Nicholas II, and his family,  claimed 2013. They have all been wrong. Harari might be no different.

Or... Harari's argument is vast and all-encompassing. He has thrown so many darts at the wall that some must hit their target. But it is equally difficult to imagine that everything he predicts is correct.