Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

We don’t become satisfied by leading a peaceful and prosperous existence. Rather, we become satisfied when reality matches our expectations. The bad news is that as conditions improve, expectations balloon. Dramatic improvements in conditions, as humankind has experienced in recent decades, translate into greater expectations rather than greater contentment.

This is the paradox of historical knowledge. Knowledge that does not change behaviour is useless. But knowledge that changes behaviour quickly loses its relevance. The more data we have and the better we understand history, the faster history alters its course, and the faster our knowledge becomes outdated.

If this is true, it implies that all the pain and pleasure experienced by billions of creatures for millions of years is just mental pollution.

The Turing Test is simply a replication of a mundane test every gay man had to undergo in 1950s Britain: can you pass for a straight man?

Turing knew from personal experience that it didn’t matter who you really were – it mattered only what others thought about you.

Because large numbers of people behave in a fundamentally different way than do small numbers.

And the years pass. As the historian watches, the web of meaning unravels and another is spun in its stead. John’s parents die, followed by all his siblings and friends. Instead of minstrels singing about the crusades, the new fashion is stage plays about tragic love affairs. The family castle burns to the ground and, when it is rebuilt, no trace is found of Grandpa Henry’s sword. The church windows shatter in a winter storm and the replacement glass no longer depicts Godfrey of Bouillon and the sinners in hell, but rather the great triumph of the king of England over the king of France. The local priest has stopped calling the Pope ‘our holy father’ – he is now referred to as ‘that devil in Rome’. In the nearby university scholars pore over ancient Greek manuscripts, dissect dead bodies and whisper quietly behind closed doors that perhaps there is no such thing as the soul.

if an English youth decided to join Amnesty International and travel to Syria to protect the human rights of refugees, he will be seen as a hero. In the Middle Ages people would have thought he had gone bonkers.

That’s how history unfolds. People weave a web of meaning, believe in it with all their heart, but sooner or later the web unravels, and when we look back we cannot understand how anybody could have taken it seriously.