Homo Deus: A Brief History of Tomorrow Hardcover – February 21, 2017

Yuval Noah Harari's "Homo Deus" continues the tradition introduced in his previous book "Sapiens": clever, clear and humorous writing, intelligent analogies and a remarkable sweep through human history, culture, intellect and technology. In general it is as readable as "Sapiens" but suffers from a few limitations.

On the positive side, Mr. Harari brings the same colorful and thought-provoking writing and broad grasp of humanity, both ancient and contemporary, to the table. He starts with exploring the three main causes of human misery through the ages - disease, starvation and war - and talks extensively about how improved technological development, liberal political and cultural institutions and economic freedom have led to very significant declines in each of these maladies. Continuing his theme from "Sapiens", a major part of the discussion is devoted to shared zeitgeists like religion and other forms of belief that, notwithstanding some of their pernicious effects, can unify a remarkably large number of people across the world in striving together for humanity's betterment. As in "Sapiens", Mr. Harari enlivens his discussion with popular analogies from current culture ranging from McDonald's and modern marriage to American politics and pop music. Mr. Harari's basic take is that science and technology combined with a shared sense of morality have created a solid liberal framework around the world that puts individual rights front and center. There are undoubtedly communities that don't respect individual rights as much as others, but these are usually seen as challenging the centuries-long march toward liberal individualism rather than upholding the global trend.

The discussion above covers about two thirds of the book. About half of this material is recycled from "Sapiens" with a few fresh perspectives and analogies. The most important general message that Mr. Harari delivers, especially in the last one third of the book, is that this long and inevitable-sounding imperative of liberal freedom is now ironically threatened by the very forces that enabled it, most notably the forces of technology and globalization. Foremost among these are artificial intelligence (AI) and machine learning. These significant new developments are gradually making human beings cede their authority to machines, in ways small and big, explicitly and quietly. Ranging from dating to medical diagnosis, from the care of the elderly to household work, entire industries now stand to both benefit and be complemented or even superseded by the march of the machines. Mr. Harari speculates about a bold vision in which most manual labor has been taken over by machines and true human input is limited only to a very limited number of people, many of whom because of their creativity and demand will likely be in the top financial echelons of society. How will the rich and the poor live in these societies? We have already seen how the technological decimation of parts of the working class was a major theme in the 2016 election in the United States and the vote for Brexit in the United Kingdom. It was also a factor that was woefully ignored in the public discussion leading up to these events, probably because it is much easier to provoke human beings against other human beings rather than against cold, impersonal machines. And yet it is the cold, impersonal machines which will increasingly interfere with human lives. How will social harmony be preserved in the face of such interference? If people whose jobs are now being done by machines get bored, what new forms of entertainment and work will we have to invent to keep them occupied? Man after all is a thinking creature, and extended boredom can cause all sorts of psychological and social problems. If the division of labor between machines and men becomes extreme, will society fragment into H. G. Wells's vision of two species, one of which literally feeds on the other even as it sustains it?

These are all tantalizing as well as concerning questions, but while Mr. Harari does hold forth on them with some intensity and imagination, this part of the book is where his limitations become clear. Since the argument about ceding human authority to machines is also a central one, the omission also unfortunately appears to me to be a serious one. The problem is that Mr. Harari is an anthropologist and social scientist, not an engineer, computer scientist or biologist, and many of the questions of AI are firmly grounded in engineering and software algorithms. There are mountains of literature written about machine learning and AI and especially their technical strengths and limitations, but Mr. Harari makes few efforts to follow them or to explicate their central arguments. Unfortunately there is a lot of hype these days about AI, and Mr. Harari dwells on some of the fanciful hype without grounding us in reality. In short, his take on AI is slim on details, and he makes sweeping and often one-sided arguments while largely skirting clear of the raw facts. The same goes for his treatment for biology. He mentions gene editing several times, and there is no doubt that this technology is going to make some significant inroads into our lives, but what is missing is a realistic discussion of what biotechnology can or cannot do. It is one thing to mention brain-machine interfaces that would allow our brains to access supercomputer-like speeds in an offhand manner; it's another to actually discuss to what extent this would be feasible and what the best science of our day has to say about it.

In the field of AI, particularly missing is a discussion of neural networks and deep learning which are two of the main tools used in AI research. Also missing is a view of a plurality of AI scenarios in which machines either complement, subjugate or are largely tamed by humans. When it comes to AI and the future, while general trends are going to be important, much of the devil will be in the details - details which decide how the actual applications of AI will be sliced and diced. This is an arena in which even Mr. Harari's capacious intellect falls short. The ensuing discussion thus seems tantalizing but does not give us a clear idea of the actual potential of machine technology to impact human culture and civilization. For reading more about these aspects, I would recommend books like Nick Bostrom's "Superintelligence", Pedro Domingos's "The Master Algorithm" and John Markoff's "Machines of Loving Grace". All these books delve into the actual details that sum up the promise and fear of artificial intelligence.

Notwithstanding these limitations, the book is certainly readable, especially if you haven't read "Sapiens" before. Mr. Harari's writing is often crisp, the play of his words is deftly clever and the reach of his mind and imagination immerses us in a grand landscape of ideas and history. At the very least he gives us a very good idea of how far we as human beings have come and how far we still have to go. As a proficient prognosticator Mr. Harari's crystal ball remains murky, but as a surveyor of past human accomplishments his robust and unique abilities are still impressive and worth admiring.

This book is a mixed bag. It has three parts. The first is a review of some of the concepts explored in Harari's earlier book Sapiens. It elaborates on the fascinating concept of "intersubjective reality", whereby concepts that are shared in our collective imagination have great power to shape our objective reality; examples given include money, corporations, pop-culture brands, and religions. Part 1 is engaging and insightful, and deserves 4/5 stars.

Part 2 is a critique of what Harari calls "humanism". He really dislikes humanism: he inaccurately states its tenets, and then repeatedly mocks it (for example, as promoting indulgent consumerism and sex). He claims that humanism is what is giving rise to an emerging cybernetic dystopia, described in Part 3.

Harari is abusing the word "humanism," as a canvas on which to paint his caricature of modern liberal culture ("liberal" in the classical sense, not in the sense of left-wing politics). He is not really interested in what humanist writers and philosophers have actually said, and does not reference their works. He claims that humanism promotes the belief in a supernatural free will (when in fact, humanists value agency and freedom, but have differing opinions on free will). He claims that humanism believes in an indivisible self/soul (when in fact, psychologists since Freud have a different understanding). And he claims that humanism believes that individuals always know best about their own needs (when in fact, many have emphasized the importance of education in our development--he does not even reference John Dewey). Harari also co-opts related terms that already have other established meanings, such as "evolutionary humanism" and "liberal humanism".

If you want to understand humanism or other social-political movements of the 19th and 20th centuries, Harari will lead you astray. Part 2 deserves only 2/5 stars.

Part 3 is a dire prediction for humanity's future, as genetic engineering, AI, and human-machine interface technologies advance. Harari gives several scenarios, each of which are described very plausibly as future extrapolations of current trends. These scenarios are thought provoking and disturbing--we as a society should be taking them more seriously. There is an interesting discussion of an emerging religion/ideology of "dataism", wherein moral worth depends on the ability to enhance data flow, rather than on consciousness. Part 3 deserves 4/5 stars.

For most of the book, Harari appears to be adopting a materialistic perspective, and one which is also extremely unsentimental and discounts the significance of human morale and character. He pretends to assume that human beings are nothing more than algorithms.

However, some of his arguments (against the existence of an indivisible self, against free-will) are similar to those in Buddhism. He also discusses how animals and people have consciousness and subjective experiences, and presumes that artificial intelligence will remain unconscious (the "weak AI" hypothesis of John Searle).

And on the very last page, he makes us wonder if his hardcore materialistic perspective has just been a long, extended ruse: he asks us to question a worldview that would deny the significance of consciousness. So it seems likely that in a future book he will focus on the nature of consciousness, and argue for non-theistic Buddhism (an understated agenda in Harari's writing--perhaps he thinks that this is the way for humanity to avoid the grim fate predicted here?).

The reader concerned about techno-dystopia may also be interested in "Weapons of Math Destruction," by Cathy O'Neil.

[Update 6/13/2017: see the comment below, by kaiser100, for further insight into Harari's perspective on consciousness and meditation. The comment begins with "Harari indeed believes that developing an understanding of consciousness, a science of mind, or however else one wishes to phrase it is the best and perhaps the only way to avert the grim fate that threatens humanity in this century."]