Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

This is the paradox of historical knowledge. Knowledge that does not change behaviour is useless. But knowledge that changes behaviour quickly loses its relevance.

Take, for example, a software engineer earning $100 per hour working for some hi-tech start-up. One day her elderly father has a stroke. He now needs help with shopping, cooking and even bathing. She could move her father to her own house, leave for work later in the morning, come back earlier in the evening and take care of her father personally. Both her income and the start-up’s productivity would suffer, but her father would enjoy the care of a respectful and loving daughter. Alternatively, the engineer could hire a Mexican carer who, for $12 per hour, would live with the father and provide for all his needs. That would mean business as usual for the engineer and her start-up, and even the carer and the Mexican economy would benefit. What should the engineer do? Free-market capitalism has a firm answer. If economic growth demands that we loosen family bonds, encourage people to live away from their parents, and import carers from the other side of the world – so be it. This answer, however, involves an ethical judgement rather than a factual statement. When some people specialise in software engineering while others devote their time to care of the elderly, we can no doubt produce more software and give old people more professional care. Yet is economic growth more important than family bonds? By presuming to make such ethical judgements, free-market capitalism has crossed the border from the land of science into that of religion.

In medieval Europe, the chief formula for knowledge was: Knowledge = Scriptures × Logic.* If people wanted to know the answer to an important question, they would read scriptures and use their logic to understand the exact meaning of the text.

The Scientific Revolution proposed a very different formula for knowledge: Knowledge = Empirical Data × Mathematics.

As humans gained confidence in themselves, a new formula for acquiring ethical knowledge appeared: Knowledge = Experiences × Sensitivity.

Democratic elections usually work only within populations that have some prior common bond, such as shared religious beliefs or national myths. They are a method to settle disagreements among people who already agree on the basics.

twenty-first century three practical developments might make this belief obsolete: 1. Humans will lose their economic and military usefulness, hence the economic and political system will stop attaching much value to them. 2. The system will continue to find value in humans collectively, but not in unique individuals. 3. The system will still find value in some unique individuals, but these will constitute a new elite of upgraded superhumans rather than the mass of the population.

1. Organisms are algorithms. Every animal – including Homo sapiens – is an assemblage of organic algorithms shaped by natural selection over millions of years of evolution. 2. Algorithmic calculations are not affected by the materials from which the calculator is built. Whether an abacus is made of wood, iron or plastic, two beads plus two beads equals four beads. 3. Hence there is no reason to think that organic algorithms can do things that non-organic algorithms will never be able to replicate or surpass. As long as the calculations remain valid, what does it matter whether the algorithms are manifested in carbon or silicon?

Laypeople believe that the economy consists of peasants growing wheat, workers manufacturing clothes, and customers buying bread and underpants. Yet experts see the economy as a mechanism for gathering data about desires and abilities, and turning this data into decisions.

Capitalism uses distributed processing, whereas communism relies on centralised processing. Capitalism