Overview
The sequel to Sapiens, Homo Deus examines what might happen when humanity's age-old problems — famine, plague, and war — are largely solved and replaced by new ambitions: immortality, happiness, and divinity. Harari explores how technology and artificial intelligence may reshape the future of our species.
Harari's follow-up to Sapiens, published in 2016, pivoted from the past to speculations about the future. The book argues that humans, having solved (at least in aggregate) the historical problems of famine, plague, and war, will turn next to upgrading themselves into something post-human through biotechnology, AI, and data religion. It has aged unevenly in the decade since.
Key Ideas
Dataism
Data is becoming the new religion, and algorithms may know us better than we know ourselves.
The useless class
AI and automation may create a massive class of economically irrelevant humans.
Upgrading humans
Biotechnology and AI will allow some humans to upgrade themselves, potentially splitting humanity into biological castes.
The end of humanism
As algorithms surpass human decision-making, the idea that human feelings are the supreme authority may dissolve.
Who should read this
Readers who loved Sapiens and want more. Also useful for people thinking about the long-term implications of AI and biotech, though Harari is better at provocative framings than at careful prediction. The first third — on the aggregate conquest of famine, plague, and war — is very strong.
Who might skip it
Skip if you're short on time — Homo Deus has less internal discipline than Sapiens and sprawls. Skip also if you've read Sapiens recently; the first hundred pages are a partial recap. The predictions about social media as a 'new religion' already look dated.
The verdict
A flawed but thought-provoking sequel. Harari's gift for the big frame is still present, but without the anchor of historical evidence (which constrained Sapiens) his prose drifts into speculation that is more entertaining than rigorous. The chapter on 'dataism' reads like it was written before the current AI wave and doesn't hold up. Read the first third and stop.
"In the twenty-first century, those who ride the train of progress will acquire divine abilities of creation and destruction, while those left behind will face extinction."
— Yuval Noah Harari, Homo Deus: A Brief History of Tomorrow
If you liked this
21 Lessons for the 21st Century, Harari's third book, is weaker still. For serious futurism, try Superintelligence by Bostrom or The Singularity Is Near by Kurzweil.