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Homo Deus - Book summary

Today, humankind (Homo Sapiens) has dominated the world, and gained control of famine, plague and war under control. Yuval Noah Harari believes that, in a healthy, prosperous and harmonious world, mankind will turn our attention to our desire for eternal youth and happiness, and that these pursuits could ironically bring an end to our species and herald a new age of Homo Deus. Harari examines our past, present and future, and highlights some difficult questions and choices that could shape our collective future.  In this summary, we’ll give an overview of these key ideas.

Homo Deus summary_Overview

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Let’s take a quick look at how humans came to dominate this world, and the possible futures in store for us if we were to continue our current path.

How Humans Conquered the World

Homo sapiens are the first species to single-handedly change the world’s ecology in 4 billion years since life first appeared on Earth. Today, 90% of the large animals around the world are either humans or our domesticated animals.

It’s important to understand how we came to where we are, and how we justify our place in the world, so we can understand our actions and see our possible futures more clearly. Harari presents many thought-provoking ideas, facts and examples. Here’s an overview (do get more details/ examples from the book or our full book summary).



Homo Deus summary_homo sapiens to homo deus

Beliefs & ideologies

Harari details how our beliefs, ideologies, and relationships with other living creatures have evolved over time, from Animism (during the times of the hunter-gatherers) to Theism (during the Agricultural Revolution), and Humanism (during the Scientific Revolution). [Get more details in our full 13-page book summary]. Essentially, Theism was only popularized during the Agricultural Revolution. People believed that the Gods favored humans over other species, and this gave  us justification to domesticate other animals and even offer them as sacrifices in return for the Gods’ blessings. During the Scientific Revolution, Gods were slowly removed from the picture,as humans could now use sciences to heal ourselves, improve crops, breed animals and forecast the weather—all without the Gods’ assistance.

Are we truly enlightened beings?

Humans want to believe that we’re special and are enlightened beings. However, Harari explains why (a) we probably don’t have eternal souls, and (b) we’re not unique in having consciousness (yes, animals and even non-organic beings can have consciousness too).

Instead, he argues that all organisms are algorithms, and many of these algorithms are woven into our genetic makeup from millions of years of evolution. When we mass-breed animals for their meat  and produce, we actually cause them much suffering due to the neglect of their inborn social/emotional needs. Even if humans are more intelligent and powerful than other animals, does that justify how we treat them? If a superior species Homo Deus were to emerge, will they treat Homo Sapiens the same way?

Get a copy of this thought-provoking book for more facts, details and examples!

Harari moves on to explain the real reason why we became the dominant species: because mankind has the unique ability to imagine, create stories and meaning, which in turn allows us to organize ourselves flexibly in large numbers (something no other animals can do).

In the book / our full Homo  Deus summary, we elaborate on how societies have been organized around the same algorithms (but different stories) across the centuries, why ancient Egypt/Pharaohs are similar to big corporations/Google, and how our ability to create meaning and spin stories enabled us to create legal systems, stock-markets, global trade, etc. In short, human societies are held together by a self-perpetuating web of meaning, and we can’t really distinguish between fact and fiction.

Science and Religion

Science and Religion are complementary and should coexist side by side. Science gives us power, using fact-based solutions to produce food, cure diseases, and fight wars. However, it can’t make ethical judgments to tell us how to act. Religions are basically rules that’re attributed to a wider moral law, and thus provide order, subjective goals, and guidelines on what we should do. In the book / full summary, we elaborate on the vital roles of both, and why it’s crucial for religions to understand modern technology, to offer guidance on real-world issues, like: What can we do when artificial intelligence replaces our jobs? Where do we draw the line for gene enhancements and life extensions?

With the power to create meaning and scientific solutions, humans can choose to do anything. The purpose we serve, the stories we choose, and our ability to separate fact from fiction, will shape our collective social, political and economic outcomes.


Where are Humans headed as a species?

In the book Harari addresses various developments and perspectives that are shaping our future, and the dilemmas that they bring. We’ll outline them very briefly here–do get a detailed overview from our complete summary.

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Capitalism and Growth

Capitalism has brought mankind amazing growth, progress, power and control. However, Capitalism assumes the wheel of growth will spin constantly and indefinitely. The dilemma is this: continuing our growth will likely lead to a total ecological collapse, but stopping the wheel of growth can crash our global systems. Will mankind ever be prepared to slow down our growth to address the ecological crisis?

The New Human Agenda

Besides our need for never-ending growth, humans also have ambitions for immortality (eternal youth) and lasting happiness. In the book / full summary, we look at what could happen as humans push for more growth and biological upgrades, and why we may end up with a new species of Homo Deus that is no longer human.

The Humanist Revolution

Humanism is the dominant religion today, placing humans at the centre of the universe. We no longer depend on the Gods and religious scriptures to tell us what’s good or right, but believe in our free will, and depend on our inner feelings and desires to guide our decisions. In the book / full 13-page summary, we explain the 3 sub-branches to Humanism, why our modern ideals are built  on myths, and why humans may eventually lose our value as unique individuals. This could come with 3 possible developments/ scenarios: (i) we become obsolete as computers become more intelligent, (ii) we become increasingly reliant on technology to make our decisions, until one day they know us better than we know ourselves, and (iii) a small group of elite, upgraded superhumans emerge to dominate other humans using technology and computer algorithms.

Digest these powerful ideas in minutes with our summary & infographic!

Other Details in “Homo Deus”

This is a comprehensive and thought-provoking book, filled with research, examples, theories and hypotheses. Most of Harari’s ideas are not prophecies, but a projection of our possible futures, based on lessons from our own history.

Our choices today are what will define our future outcomes. Harari prompts us to ponder questions like: Are organisms really algorithms? What if our life expectancy is doubled to 150 years old or more? What will happen if algorithms can know us better than we know ourselves, or a superior species were to emerge? What’s more valuable: intelligence or consciousness?

Do get a copy of the book for the full details, get our Homo Deus summary bundle for a detailed overview of the key ideas and examples, visit for more information, or read more about the history of mankind in our Sapiens book summary here.

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