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The Age of Em: Work, Love and Life When Robots Rule the Earth

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Robots may one day rule the world, but what is a robot-ruled Earth like?
Many think the first truly smart robots will be brain emulations or "ems." Scan a human brain, then run a model with the same connections on a fast computer, and you have a robot brain, but recognizably human.
Train an em to do some job and copy it a million times: an army of workers is at your disposal. When they can be made cheaply, within perhaps a century, ems will displace humans in most jobs. In this new economic era, the world economy may double in size every few weeks.
Some say we can't know the future, especially following such a disruptive new technology, but Professor Robin Hanson sets out to prove them wrong. Applying decades of expertise in physics, computer science, and economics, he uses standard theories to paint a detailed picture of a world dominated by ems.
While human lives don't change greatly in the em era, em lives are as different from ours as our lives are from those of our farmer and forager ancestors. Ems make us question common assumptions of moral progress, because they reject many of the values we hold dear.
Read about em mind speeds, body sizes, job training and career paths, energy use and cooling infrastructure, virtual reality, aging and retirement, death and immortality, security, wealth inequality, religion, teleportation, identity, cities, politics, law, war, status, friendship and love.
This book shows you just how strange your descendants may be, though ems are no stranger than we would appear to our ancestors. To most ems, it seems good to be an em.

448 pages, Hardcover

First published April 1, 2016

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About the author

Robin Hanson

12 books183 followers
Robin Hanson is an associate professor of economics at George Mason University and a research associate at the Future of Humanity Institute of Oxford University. He has a doctorate in social science, master's degrees in physics and philosophy, and nine years of experience as a research programmer in artificial intelligence and Bayesian statistics. With over 3100 citations and sixty academic publications, he's recognized not only for his contributions to economics (especially, pioneering the theory and use of prediction markets), but also for the wide range of fields in which he's been published. He is the author of The Age of Em: Work, Love, and Life when Robots Rule the Earth (OUP 2016).

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Profile Image for Mark Hebwood.
Author 1 book97 followers
February 15, 2023
Frustration and Incredulity

Well... this was a complete waste of time, a surprisingly pointless and, dare I say it, sloppy, attempt at projecting a possible future.

An era in which brain simulations run on computer hardware and allow the original owner of the consciousness to live on forever in her digitalised incarnation holds astounding opportunities, and intimidating risks. Such a technology would potentially alter society into something that differs from what we know today at the level of its DNA. A person living today would find such a future far less intuitive than a person from ancient Egypt (for example) would find ours.

Not that I gathered this impression from Robin's book. I got that from Alastair Reynolds extaordinary imagination. What Robin gave me was frustration, and incredulity. Frustration that a projection of the future that claims to be detailed and scientific was based on handwavy and unsubstantiated claims, and incredulity that a person of Robin's academic standing would be satisfied to build his projection on such a brittle foundation.

Rough and ready

Very early on, Robin jumps in with a discussion of population growth. Social group sizes have steadily increased over ... history, we read on page 13. ... most mammals live in groups of two to 15 individuals..., most human foragers lived in bands of roughly 20 to 50. Most farmers lived in village-based communities of roughly 500 to 2000... . ... Today, most people live in metropolitan regions of roughly 100 000 to 10 million... . ... These sizes fit a simple if mysterious pattern: each era's community sizes have been roughly the square of the previous era's sizes... .

Let's see how good the fit of this model is, shall we?
(i) A band should be the square of a group, ie 4-225. This compares to an observed value of 20-50. The prediction error is -80% to 350% for this category.
(ii) A village should be the square of a band, ie 400-2500, compared to observation of 500-2000. Prediction error -20% to 25%.
(iii) A city should be the square of a village, ie 250,000 - 4 million, against observation of 100,000 to 10 million. Error 150% to -60%.

Hm. I would call that a bit vague, to say the least. Certainly I am not going to employ Robin as my pension adviser... But does he not put caveats in, you might say in his defense? He said "roughly", after all. In fact he said it so often that it became a mantra in that short paragraph.

At this point I must declare myself, I am afraid. Estimates and projections are the daily bread and butter of my job, indeed my profession. So I have an intuitive handle on what sort of error I would classify as "rough". If an observed value comes in within 0-2% of my estimate, I would call that "in line". 5% is still "broadly in line", but anything outside of 10% is very definitely a "beat" or a "miss". There are some dynamics that are naturally volatile, and for those I would still say an error of ~20% is within reason, but I would indeed use Robin's expression and call it "rough".

So only one category in Robin's model fits what I would see as a reasonable calibration of the label "rough". I do not think a predictive model that produces results 80% lower or 3.5x higher than the actual values deserves to be called "predictive".

Unfortunately, Robin chose to open his account with a description of this "model", and by doing so pretty much destroyed his credibility in my eyes.

But it is possible to forecast the future.

Robin himself must have felt that his methods are a bit "rough", to use his own words. Just a few pages later, in the section "Forecasting", he establishes that it is possible to forecast the future, in a refutation of the opposite claim that he must have seen as plausible pushback.

Or did he. Actually, the section strikes me more as pleading, than arguing. He states that lots of authors accurately forecast the future, and identifies their works. Herman Kahn and Anthony Wiener, for example, were "80% correct for computer and communication technology, and 50% correct for other technology" (page 33).

Well that is just astounding I have to admit. Eighty per cent! Wow. Maybe I am wrong and the future can be predicted. So how is the metric calculated? What is being counted here? Did they get 80 applications right, out of 100? Robin doesn't say. Shame. Presumably we have to read the books he quoted. But hey - eighty is still a high number so that's good. 50% is not so good, but then what do we expect? That percentage applies to "other technology", so every man-made apparatus that is not a computer or a telephone. Pretty good to get half of that one right, and I can even forgive him for not saying what the percentage relates to. He's a busy guy, and anyway if I have to be unreasonable and sceptical, I might as well go and read those other books, too.

But that's not all. Robin is on a roll. A page later, he notes that "many say that while physical possibilities can be foreseen, social consequences cannot. Such people are often trained in physical sciences, and don't appreciate that social scientists do in fact know many useful things." (p 34). Exactly! You tell them, Robin. "Such people"... gosh how I hate them. Sooo superficial. Social scientists are not complete morons, they know useful things. Thank you Robin, the world needed to hear that.

What do they know, Robin? Can you tell us? "For example, social scientists today understand in some detail why our ways of life differ from those of farmers, and why farmers' ways differ from foragers' ways" (p 34). Oh man. That is great. Well that's just it then. We can forecast the future. Just why dont more people do it, Robin?

"Forecasters do not tend to be much rewarded for such efforts, either culturally or materially. This helps to explain why there are relatively few serious forecasting efforts." (p34) Outrageous! Thanks for saying that, Robin. Such talents, all gone to waste.

"But make no mistake, it is possible to forecast the future." (p 34) Absolutely. You demonstrated that beyond a shadow of a doubt, Robin. Very good.

I assume

And so it goes on. Robin pleads to believe him, he makes assumptions without explaining why they would be plausible, and draws conclusions without arguing a case. A few pages on, we find this discourse:

"... I make the following concrete assumptions about emulations. I assume that sometime in roughly the next century it will be possible to scan a human brain at a fine enough spatial and chemical resolution, and to combine that scan with good enough models of how individual brain cells achieve their signal processing functions, to create a cell-by-cell dynamically executable model of the full brain in artificial hardware, a model whose signal input-output behavior is usefully close to that of the original brain."

Excellent. Allow me to focus on two phrases from this morass of pseudo-scientific gobbledygook. The first is "roughly the next century". There is Robin's calibrated yardstick again. We know what that means now. "Roughly" refers to an error margin between -80% and 350%. The next century is 83-183 years away. This means Robin's estimate translates into a range of between 17 and 374 years. So that's a rather wider timeframe than "next century". But of course Robin probably changes his mind of what "roughly" refers to from one page to the next.

The second phrase is "usefully close". Another uselessly distant metaphor. What's useful when we talk about brain functions? Did Robin define this term anywhere? Of course not. Why would he. Are there perhaps references to reams of other books that he dismissively throws at the reader who dares to become frustrated with his uselessly vague language? No. Not even. So we are on our own on this one.

I could go on, but I will stop now. I was diving in and out of the book, as Robin suggested we do, but I could find no chapter that would stand up to a rigorous scientific or scholarly standard. But maybe I missed it. If I did, I may be forgiven - often, Robin's writing style somewhat detracts from what he might have wanted to say....

Sometimes the confusion is on a morphological level: "It costs a logarithmic-in-time overhead of extra parallel processor and memory units to reversibly erase the results of intermediate computing steps in the background" (p79).

And sometimes Robin simply does not grasp the concept of a full-stop as a punctuation mark that "usefully" (see what I did there?) helps mark the end of one thought, and allows the start of another: "Because of this, we expect the physical variables ... within the brain that encode signals and signal-relevant states, which transform these signals and states, and which transmit them elsewhere, to be overall rather physically isolated and disconnected from the other far more numerous unrelated physical degrees of freedom and processes in the brain." (p46).

Well. My mental degrees of freedom have been severely curtailed after reading (parts of) this book. I am back with Alastair Reynolds as I am writing this.
Profile Image for Brian Clegg.
Author 214 books2,873 followers
June 7, 2016
I recently said about Timandra Harkness's Big Data, 'welcome to the brave new world', but if there were ever a book to fully reflect Shakespeare's complete original line in The Tempest, 'O brave new world that has such people in't', it is surely Robin Hanson's new book The Age of Em.

I don't know if it was done so the book title would echo 'age of empire' , but I find the author's term for uploaded personalities 'ems' a little contrived, like many made-up names - it's just a bit too short for what he covers. (And sounds far too like a shortening of Emma.) However there is no doubt that what Hanson is doing here is truly fascinating. It is far more than the lame subtitle 'work, love and life when robots rule the Earth' suggests, as is it's not about robots. It is attempting to forecast the nature of a world dominated by electronic 'people', initially created by uploading the mental patterns of humans.

What Hanson does brilliantly is to take the reader through all the different implications of such a world. Implications that simply won't have occurred even to many science fiction writers. What, for example, would happen if a single person is copied many times to make a slave army? How would the ems interact socially? What would their civilisation be like? I've never seen a book that took this idea to such a detailed logical extreme.

Unfortunately, despite the brilliance of the concept, the execution is not at the same level. It's like a non-fiction equivalent of Tolkien's The Silmarillion. If you are interested in the subject, it feels like something that ought to be a delight, but in fact the plodding academic writing, based on making repeated statements with no narrative flow, make it a pain of a book to read. We get exactly the same here as in The Silmarillion, with the added joy of inline Harvard-style references, which make it even harder to get any pleasure from reading it.

I think the best way to describe The Age of Em as is as a theory of science fiction book. Although Hanson is of the opinion that his vision of a world dominated by uploaded personalities will be possible within 100 years, I suspect that the complexity of scanning a brain to the level of individual neurons, their connections, their chemical makeups and electrical balances will take rather longer to achieve. What's more, the author proudly tells us that he intends to have his brain frozen when he dies with the hope of one day becoming an em. If making this happen with living people is difficult, the chances of a personality remaining in a frozen brain that could even approximate to the original are negligible - think more of the episode in Buffy the Vampire Slayer when her dead mother is brought back. Not advisable.

The other reason I'd label this theory of science fiction is that the whole business of futurology has always been terribly inaccurate. Niels Bohr was spot on when he said 'predictions can be very difficult - especially about the future.' Hanson attempts to defend the accuracy of futurology by pointing out specific examples that have come up with a surprisingly accurate prediction. But when you look at those examples, the accuracy is mostly retrofitted with hindsight. More to the point, this is a classic example of the scientific no-no of cherry picking. You don't show that something is effective by picking out the handful of cases where it has worked and ignoring the many thousands where it hasn't worked. Statistically, some guesses about the future are bound to be correct - but that doesn't make them accurate forecasts, it makes them lucky.

So don't expect a great work of popular science (to be fair, given those inline references, I don't think the author intended it to be popular science). But if you can put the effort in and grind through it, there are some genuinely fascinating considerations about what a society of uploaded individuals might be like. In fact, I'd say any science fiction author worth his or her salt should be rushing out and buying a copy of this book. There are enough ideas here to spark off a thousand stories.
Profile Image for Gavin.
1,114 reviews411 followers
July 15, 2018
Believe me that it's remarkable; it's easily in the top 5 most insightful books out of the 500 I have reviewed here. I called Superintelligence the most rigorous exploration of the nonreal I had ever read: this beats it by a lot. You will find yourself reading pages on the properties of coolant pipes and be utterly engrossed. It is imaginary sociology, imaginary economics, real fiction.

(But it lacks an ethnography entirely: no em speaks to us themselves.)

People tend to wrap Age of Em in ulterior motives and esoteric intentions, because they love it but see futurism as an unworthy goal for such an achievement. I am no different: this is the greatest compendium of real social science I have ever found.

No review can do much justice, but here's one particularly hair-raising point in it: Hanson surveys the whole course of human history, and notes the many ways our culture is unprecedented and, in the evolutionary sense, nonadaptive:

we live in the brief but important “dreamtime” when delusions [drive] history. Our descendants will remember our era as the one where the human capacity to sincerely believe crazy non-adaptive things, and act on those beliefs, was dialed to the max.

Why is our era so delusory?


Our knowledge has been growing so fast, and bringing such radical changes, that many of us see anything as possible, so that nothing can really be labeled delusion.

Rich folks like us have larger buffers of wealth to cushion our mistakes; we can live happily and long even while acting on crazy beliefs.

We humans evolved to signal various features of ourselves to one another via delusions; we usually think that the various things we do to signal are done for other reasons. For example, we think we pay for docs to help our loved ones get well, rather than to show that we care. We think we do politics because we want to help our nation, rather than to signal our character and loyalty. We are overconfident in our abilities in order to convince others to have confidence in us, and so on. But while our ancestors’ delusions were well adapted to their situations, and so didn’t hurt them much, the same delusions are not nearly as adapted to our rapidly changing world; our signaling induced delusions hurt us more.

Humans seem to have evolved to emphasize signaling more in good times than in bad. Since very few physical investments last very long, the main investments one can make in good times that last until bad times are allies and reputation. So we are built to, in good times, spend more time and energy on leisure, medicine, charity, morals, patriotism, and so on. Relative to our ancestors’ world, our whole era is one big very good time.

Our minds were built with a near mode designed more for practical concrete reasoning about things up close, and a far mode designed more for presenting a good image to others via our abstract reasoning about things far away. But our minds must now deal with a much larger world where many relevant things are much further away, and abstract reasoning is more useful. So we rely more than did our ancestors on that abstract far mode capability. But since that far mode was tuned more for presenting a good image, it is much more tolerant of good-looking delusions.

Tech now enables more exposure to mood-altering drugs and arts, and specialists make them into especially potent “super-stimuli.”... today drugs are cheap, we can hear music all the time, most surfaces are covered by art, and we spend much of our day with stories from TV, video games, etc. And all that art is made by organized groups of specialists far better than the typical ancestral artist.

We were built to be influenced by the rhetoric, eloquence, difficulty, drama, and repetition of arguments, not just their logic. Perhaps this once helped us to ally us with high status folks. And we were built to show our ideals via the stories we like, and also to like well-crafted stories. But today we are exposed to arguments and stories by folks far more expert than found in ancestral tribes. Since we are built to be quite awed and persuaded by such displays, our beliefs and ideals are highly influenced by our writers and story-tellers. And these folks in turn tell us what we want to hear, or what their patrons want us to hear, neither of which need have much to do with reality.


These factors combine to make our era the most consistently and consequentially deluded and unadaptive of any era ever. When they remember us, our distant descendants will be shake their heads at the demographic transition, where we each took far less than full advantage of the reproductive opportunities our wealth offered. They will note how we instead spent our wealth to buy products we saw in ads that talked mostly about the sort of folks who buy them. They will lament our obsession with super-stimuli that highjacked our evolved heuristics to give us taste without nutrition. They will note we spent vast sums on things that didn’t actually help on the margin, such as on medicine that didn’t make us healthier, or education that didn’t make us more productive.

Our descendants will also remember our adolescent and extreme mating patterns, our extreme gender personalities, and our unprecedentedly fierce warriors. They will be amazed at the strange religious, political, and social beliefs we acted on, and how we preferred a political system, democracy, designed to emphasize the hardly-considered fleeting delusory thoughts of the median voter rather than the considered opinions of our best experts.

Perhaps most important, our descendants may remember how history hung by a precarious thread on a few crucial coordination choices that our highly integrated rapidly changing world did or might have allowed us to achieve, and the strange delusions that influenced such choices. These choices might have been about global warming, rampaging robots, nuclear weapons, bioterror, etc. Our delusions may have led us to do something quite wonderful, or quite horrible, that permanently changed the options available to our descendants. This would be the most lasting legacy of this, our explosively growing dream time, when what was once adaptive behavior with mostly harmless delusions become strange and dreamy unadaptive behavior, before adaptation again reasserted a clear-headed relation between behavior and reality.

Our dreamtime will be a time of legend, a favorite setting for grand fiction, when low-delusion heroes and the strange rich clowns around them could most plausibly have changed the course of history. Perhaps most dramatic will be tragedies about dreamtime advocates who could foresee and were horrified by the coming slow stable adaptive eons, and tried passionately, but unsuccessfully, to prevent them.


It's easy to read a radical critique of our liberal values in there, but I believe him when he says that he doesn't dislike dreamtime; he just predicts it cannot last, because we are fighting an old and inexorable tide.

There are several thoughts this large, and a thousand other small insights in Age of Em.
Profile Image for Atila Iamarino.
411 reviews4,429 followers
September 9, 2016
Um livro muito estranho, para dizer o mínimo. É um exercício de predição dos melhores, em uma situação muito peculiar, um futuro onde simulações de mentes humanas imperam como uma nova forma de computação. Me valeu bem mais pelos insights sobre o presente que Robin Hanson usa para extrapolar o futuro do que o cenário futuro em si, que são excelentes.

A abordagem dele de economia e sociologia para entender o presente e falar sobre o futuro é bem diferente da maioria e, espero, inspiradora. Mas o livro em si parece uma grande obra de ficção super elaborada, onde o autor pensa em todos os mínimos detalhes sobre uma situação bastante improvável (para mim). Fico esperando pela próxima obra, onde ele deve falar sobre a mente e nossos "pontos fracos", mais sobre o presente e menos sobre uma situação futura específica me é mais interessante.
Profile Image for Clare O'Beara.
Author 22 books362 followers
December 10, 2016
Ems or robot/computer brain emulations of people, are the subject of this book, with sociological implications and a note that this may be a short section of the future, replaced by something even stranger. I'm puzzled that the author speculates that ems will 'live' in a few major cities which don't have humans and the humans will all go and retire. Where to? There's already not enough land to house and feed the seven billion of us plus the few billion who'll be coming along in the next few years. The ems Hanson says will be like robot people in that they will want to work and play - play being on line environment games.

We know that we are lucky and advanced, living in this age of rapid change and improving medicine. We have not adapted quickly enough and are still adapting, the downside being that we are adapting away from being able to survive without machines and computers. Our ancestors had some peculiar and unpleasant habits, just as they would find some of our habits perplexing. So we can imagine this pattern continuing and our descendants, human or robot, being different again.

What will the em city look like? Some robot bodies and a lot of computer banks. The space will be split equally between hardware and cooling or communications equipment. (I'm wondering about pests but with no people I suppose they will just gas them.) Most ems work in teams; they are made for a purpose and enjoy fulfilling it, then retire when no longer needed. Wages will be very low. (I'm not sure what the currency would be; maybe time on games.) There will still be laws, legal agreements, secrets and privacy. Mental processes can run at different speeds - but faster than humans - while bodies can be industrial robots or microbots. But Hanson argues that sex will still be sought, for recreation, in virtual worlds where they will all look as attractive as they wish. (I don't see why the machines would want sex unless people tell them to.) One em can have an experience and share it with the whole clan so learning is fast. Ems won't fear death because their memories can be stored and accessed.

First we get a look at human past and culture transitions, and we are told that while all humans should gain from the em era, only a few will dominate. I don't see why machines should care if people have better healthcare or nice living space. Hanson adds that today's poor nations place more value on conformity, religion and authority, while rich nations value individualism, tolerance, pleasure, nature and trust. Sounds about right but I would add that this has applied to poor and wealthy individuals as well, broadly speaking. Today's rich nations are those with limited reproduction, seeming to go against the survival of the fittest demand, while poor nations have larger reproduction. Hanson says it would be hard and tricky to control global population growth - but Japan and China managed it at a stroke, not mentioned. Compliance with a modern law instead of a primitive religion seems to be the key.

Hanson asks why we want to look at our future, who would do this other than SF readers, and what they expect to see. Also what taboos this book breaks, such as humans not having any way to earn. And then we're off, with a look at scanned and rebuilt artificial brains, biological networks not built for humans to understand. Hanson was working in AI in Silicon Valley since 1984 but has gone on to other fields like economics, and says that advances have been slower than expected at the time, but some areas have been recently advancing very fast. There's a discussion on the speed of advances in hardware, algorithms and AI progress. But the author reckons that ems can exist without broad AI.

Items such as cosmic ray particles interacting with and corrupting computer performance are introduced. Moore's Law has been operating well but will be slowing. Stolen, enslaved and open source ems may be in use. This implies that one em team will steal ems from another. Parallel signal processing will be ideal for teams of ems, not linear which will leave some ems waiting for a task until others have completed theirs. Speed and the price of memory storage are considered. Cities slow down wind, channel wind, heat up and create microclimates. Em cities will be running much hotter. Cooling might be more of a limiting factor than space or power. Hanson says a slurry of salt water with ice pellets has five times the cooling capacity of water, better than cold air. A combination of cold climate and seawater may be needed, the Arctic and Antarctic would seem likely. The author doesn't mention that many big global databanks are located in Iceland, using cold air and geothermal power. The construction of cities and factories is discussed, as well as resources that would be needed.

After this it gets weird I have to say, with ems being interchangeable with Sims to the reader, having copies or spurs and retired portions, needing authentication and using black markets; and metaphysical elements like souls of ems as opposed to where their mind happens to be working coming into play. I've read a lot of speculative fiction, from thrillers to SF, dealing with advanced computing so knowing that this book is not intended to be read as SF feels rather strange. The language is scientific but reasonably accessible, with references there in the text. There are also a couple of dozen pages of close-written references at the end. As a final note the author says that major changes such as robots taking most jobs, to pick one example, will be considered when there is enough evidence of it happening; actually, this is happening even in China now.

If you know a good bit about computing and sociology this book will be very interesting. Certainly there is plenty of food for thought, and as the author says, the best guesses have been right about 50% of the time and moderately right more often. We may not have much more time to speculate before the sentient servers arrive. Who knows if the ems will want us?

I downloaded an ARC from Net Galley for an unbiased review.

You may also be interested in:
Artificial Intelligence by Richard Unwin
The Rise of the Robots by Martin Ford
The Great Acceleration by Robert Colvile
Superintelligence by Nick Bostrom.
Profile Image for Sandy Maguire.
Author 3 books174 followers
October 10, 2016
This book was a slog -- couldn't force myself to finish it. The concepts are interesting enough, but the writing is drryyyyyy.
Profile Image for Taylor Barkley.
355 reviews3 followers
September 24, 2018
A great book. Best described as a history of the future perhaps. Lots of research from diverse fields into what our brain emulation descendants and their society might look like. It’s weird; it’s plodding; it’s detailed; it’s fun. Obviously took a lot of work to write and research.
Profile Image for Nathan Taylor.
5 reviews
June 18, 2016
Robin Hanson has written the best book I've ever read on what the future may hold. Rather than explore many alternative possibilities, he deliberately picks a single future scenario to explore in great depth. Then leaves to others to work out alternates, building from his baseline. Hanson's chosen scenario is one where humans upload their minds to computers to create human emulations or ems. He uses standard social and physical science to grind out the details of what this world might look like. As ems are zero marginal cost to copy, this means ems live in megacities which look like giant server farms gone mad, where billions, possibly trillions of copies of ems work. While some have robot bodies, most live in virtual reality in pleasant but malthusian conditions. Since these ems can run 1000x faster than regular humans, the economy doubles in months(!). While this phase might last hundreds of years in em subjective time, in calendar time it'll only be a few years. During those few years, humans can retire. Sticking to his guns, Hanson keeps his deep focus only on his core scenario, and doesn't spend time on what regular humans think or do. Or on what comes next. Though he does suggest the em era is followed by one dominated by new types of artificial general intelligence invented by the ems themselves.

That said, while Hanson writes in solid straightforward prose, he tends towards a jargon heavy, highly footnoted style. The book has no strong narrative. As I saw elsewhere, think The Silmarillion, not Lord of the Rings. Since I'm a long time reader of Robin Hanson's overcomingbias.com blog I'm familiar enough with his oeuvre to avoid getting bogged down with terms like ems, near/far mode, farmers/forager lifestyles, status signaling, coalition politics, etc. Or with Hanson analyzing ems based on his own particular take on human psychology. The book will definitely work for new readers interested in these topics, but will be a bit of a slog at times.

Hanson often notes that x is not about y, it's really about z. For example charity is not about helping, it's about signaling to others your helpfulness. In that sense, I suspect for many people Futurism is not about the future. That is, some (not all!) people who say they are interested in the future are really more interested in wish fulfillment about the present, or a utopian desire to fix things with technology, or enhancing a group's status, or just hearing an exciting adventure story. A real analysis of the future tends towards a dry, somewhat jargony, heavily footnoted tome. And that's what Hanson has written. It's a history book, though one about the future. Of course, some historians also write with great narrative power as well, and a few of those are also great historians to boot. But if I had to choose, I would take a well written, solid academic work full of quirky and often brilliant original ideas over narrative any day. So I highly recommend this book, greatly enjoyed it, and feel like I now have a slightly better view of what the future may hold. With caveats as noted.
Profile Image for Rory.
881 reviews34 followers
March 23, 2019
I wasn't smart enough for most of this book, but at least the author was smart enough to finish each section with a searing, one-sentence summary even his dimmest readers could comprendo. His primary assertion is that "ems" ("emulations"--digital versions of human-like brains) will take over the earth (not in a MEAN way or nuthin) and that this will be the next/fourth major mode of "human" existence after the forager/farmer/industrial-types all got their turn.

Definitely the kind of book I wish I could have read in the context/comfort of a college class at a small liberal arts college.
Profile Image for Alexander.
68 reviews62 followers
July 17, 2022
An interesting book attempting to forecast the future using some very reasonable assumptions. The crux of Hanson’s argument is that emulating the brain is easier than building artificial general intelligence (AGI) and hence emulated brains (ems) will happen sooner than AGI.

A recent paper by Yann LeCun (Chief AI Scientist at Meta and someone who has always been ahead of the game in the field of AI) proposes an architecture for an AGI that seems plausible based on what I know about neuroscience and AI: https://openreview.net/pdf?id=BZ5a1r-...

If LeCun is right, then AGI will happen before the age of em, and Hanson will be wrong. The possibility for the age of em happening still remains open even if AGI happens first.
Profile Image for Garrett Petersen.
1 review2 followers
June 17, 2016
[Full disclosure: I invited Robin Hanson onto my podcast, Economics Detective Radio, to discuss the book. You can hear the full interview here.]

There's so much to love in this book.

Hanson starts his foray into futurism with the assumption that we will eventually develop the technical ability to create human whole brain emulations, or "ems." That is, we will be able to scan a brain in all its detail, then simulate the functioning of that brain sufficiently well to have it mimic the thought processes of the original human.

Sounds implausible, right? Maybe not.

As Robin points out, we already have the ability to emulate ears and eyes, and we can already emulate the ways brain signals control hands and legs, so even in 2016 we can emulate the basic inputs and outputs of the brain. The key reason why we might expect whole brain emulation to be easier to develop than, say, a human-level AI, is because the relevant component parts of the brain are themselves simple. Emulation only requires us to understand the most basic building blocks of the brain, then we can copy their arrangement from nature without having to understand it ourselves.

Still not convinced? That's fine, because the real value of this book is that it will teach you a lot about our present world even if you (or your grandchildren) never end up being emulated. Robin draws from theoretical results in economics, computer science, physics, and many other fields to craft his predictions about an economy populated by ems. He looks across the broad scope of human history at the radical changes that have come in the past, from pre-human hominids to humans, from foragers to farmers, and from farmers to industrial workers to anticipate what the next radical shift might entail.

You'll learn a lot of history and science from reading this book. For instance, did you know that the cultural divide between farmers and foragers mirrors some of the deepest cultural rifts in our society? I did, because I learned it from Robin Hanson. And did you know that a fractal fluid cooling system can cool something with a cost overhead in logarithmic proportion to its size? I did, because I learned it from Robin Hanson.

If you're still not sure whether you should read The Age of Em, you can learn more by listening to my interview with the author.
Profile Image for David Gross.
Author 10 books116 followers
May 31, 2016
It's looking increasingly likely that eventually we'll be clever enough to create artificial intelligence with at least human-level capability. Two likely ways we might do this are 1) to increase the sophistication and coordination of our intelligent algorithms, or, 2) to learn how to simulate the human brain in a computer in such a way that the simulation has equivalent capabilities to the original brain. Hanson puts his bets on the second option happening first, and has written this book to explore what this era will be like as emulated brains ("ems") proliferate and organize into their own cultures.

The book is largely a set of densely-packed, fabulously multidisciplinary extrapolations from existing human historical trends, cultural varieties, and individual eccentricities that attempts to anticipate what this emerging em culture will look like before it is quickly swallowed up by whatever it invents to replace itself.

It is a difficult book to read. Hanson uses discipline-specific jargon and terms of art without pausing to explain them precisely, which often made me feel like I was floating on a cloud of gauzy sociological generalities. It's also often very difficult to figure out why Hanson (or "we" as he sometimes likes to call himself) is making a particular prediction, how confident we should feel about it and why, what the disregarded options were and why they were disregarded, and how the various predictions and their variances might be expected to interact with each other. Often he seems to just be confidently extrapolating from a tiny handful of data-points, not because there's good reason to believe that mere extrapolation has predictive power, but because if you have faith in extrapolation you can predict confidently and predicting confidently is fun. Without much to go on to evaluate his particular guesses, you just have to credit Hanson as being a very smart polymath who is obsessed about this particular topic, and take it or leave it.

This would be an invaluable resource for someone intending to write a book of cyberpunk fiction about this possible era.
Profile Image for JG.
102 reviews
April 14, 2016
To be honest I thought this book will be like the book "The next 100 years" by George Friedman. I was wrong.

This book is about a very very very specific future scenario where there are a few relegated humans and the majority of the population is made by ems (shorter for brain emulations). Some of this ems live in a virtual world and a few live in the physical world. The author makes a very thorough and detailed explanation of this fictional future and spend most of the book outlining the organization (political, economic, social) of these fictional ems and their very specific traits.

The book tries to analyze a very distant future and totally strange to us, but using today's tools and knowledge.

He doesn't qualify his book as fiction. In fact he really believes that his forecast is more accurate, realistic and plausible than any other sci-fi work. It seems he is just another victim of the conjunction fallacy.

I still find hard to conceive how "today’s standard academic consensus science" (as the author writes) could analyze in an accurate and realistic way His very specific vision of future. Following the author line of thought, it would be like asking to the foragers to forecast in a plausible and realistic way Today´s economy and socio-political organization using their cognitive tools and knowledge. It surely would seem logical and realistic and plausible to them, but not to us.

I believe that some of the author's statements (or maybe his way of expressing them) are very arrogant. He gives some examples of people who forecasted something about the future, but I think he is falling in the representativeness heuristic bias.

All in all, it is a very interesting intellectual exercise to use today consensus theories from many fields to try to understand or imagine some possible future among many other possible futures.
Profile Image for Jacob Williams.
512 reviews11 followers
September 1, 2022
By em, Hanson means emulated mind - a copy of the information that constitutes a human mind, extracted from a brain and running on a computer instead. He tries to predict the details of how this technology would impact society. I appreciate the relatively principled approach he brings to the subject:

Among the few who consider em social implications, most paint heaven or hell scenarios, or try to invent the new social sciences they imagine are needed to describe new social eras. In contrast, I seek to straightforwardly apply today's standard academic consensus science to these novel assumptions about the future. I try not to be creative or contrarian, other than by pursuing this unusual question in unusual breadth and detail.


Nevertheless, to demand predictions that we can have confidence in would be asking way too much. All I was looking for were thought-provoking ideas with some degree of plausibility. On that, Hanson delivered. The book is packed with both interesting social science references and fascinating speculation; my highlights-to-pages ratio was significantly greater than 1.


To me, it does seem like a pretty safe bet that if society survives long enough, we'll eventually develop the technology for mind emulation. There are two straightforward corollaries of that technology: we'll be able to create as many copies of any given mind as we want, and we'll be able to run minds at faster or slower speeds. Much of Hanson's book is working out the implications of those capabilities.
Some of the most unpleasant conclusions he draws also seem the most difficult to argue with, namely:


- Since it will be possible for every job to be filled by a copy of the person who is the very best at that job, there will likely be a vast number of copies of a small number of human minds - maybe less than 1000 - and everyone else combined will make up only a tiny sliver of the economy.
- Because the supply of labor is more or less limited only by the cost of the hardware for running an em, ems - even top-skilled ems - face intense competition among themselves, which should push their wages down to subsistence levels.


The sting of the first point is at least lessened a bit by Hanson's argument that, although (non-em) humans collectively will have little power, individual humans should generally be relatively wealthy, and perhaps able to finance making a few em copies of themselves and giving them comfortable endowments. There are silver linings on the second point as well; he points out that ems will have been selected for their suitability for this lifestyle (so, imagine a world full of voluntary workaholics, I guess), and also that even a poor em is free of many problems humans face: they have no physical diseases, they never go hungry, they have more control over death, they have control over their own physical appearance...

Something Hanson notes, but maybe underemphasizes, is how much would depend on exactly which humans end up being the most copied. If most political and economic power ends up in the hands of copies of a tiny subset of humans, it matters a great deal what political and moral views those humans happen to hold.
Profile Image for George.
234 reviews
July 19, 2017
I was torn by this book. The examination of a future world with human-mind-brain emulations (hence 'em') was a fascinating idea which is why I snapped up the book.

However, the outcome was a science fiction world without a storyline. The author clearly has done a lot of research and thinking about this possible future world, but chapters examining infrastructure of this world, politics and families were a bit...boring. I heartily encourage anyone who is writing science fiction about this world or something similar, as you have many great ideas discussed in painful detail.

On the other hand, the book has many good ideas that I thought could have further examination and would have enjoyed the author taking us through his reasoning to convince that he was right. As it was, it was as if he had come to his conclusions fully formed and put them down on the page. Some further criticality of his own ideas would have been useful.

In the end, it's like meeting someone who has thought a little too hard about any fictional world world, started off with some assumption and just run with it. Interesting, but a little empty.
Profile Image for Andrei Khrapavitski.
104 reviews26 followers
February 11, 2017
The work of a futurist is rarely appreciated. It is extremely hard to predict the future. Sci-Fi authors like to portray a distant future either as a dystopia where life is barely worth living or as some amazing paradise of abundance.
This work is different. Robin Hanson is an economist, and his portrayal of the world of full brain emulations or Ems is based on his reading of our current political and economic theories. He tries to imagine the world of ems through our current prism. Of course, such an approach has some drawbacks, as it would be hard to ask a prehistoric man to imagine the world in 2017, but this approach is justifiable as it is factually based. At least, for a significant part of the book. But there are many cases where conclusions are pretty stretched and can be argued. But what I am certain of is that this book will be enjoyable for those of you interested in futurism and the future of humanity. In short, the world of em is complicated. Not as fanciful and cloudless, but arguably better than what we have to day. And by a large margin.
Profile Image for Isaac.
311 reviews5 followers
March 18, 2019
I had never even considered the possibility of whole brain emulation, but Hanson sure makes a good argument for why it is likely to be the next major "age". This book is occasionally too technical for me, particularly the entropy stuff (I do enjoy saying "adiabatic" even if I can't define it), and I whiffed on groking combinatorial auctions and a few other sections. That said there is plenty of accessible stuff here, even just idea of a brain being able to run faster or slower and fork off copies at will gets trippy pretty fast. I am a little skeptical of the premise of predicting a future that far out, I probably won't be changing my life to prepare for the age of em, but I certainly think writing it is a worthwhile exercise, and I'm glad Hanson did.
Profile Image for Boris.
58 reviews5 followers
January 14, 2020
Great exploration of an interesting idea. A little dry by comparison to what you'd get out of a science fiction novel, but it's interesting to reflect on our today's society through the eyes of this possible society. I benefited from reading this book.
116 reviews47 followers
September 17, 2017
Futurism done right.

Hanson explores a scenario based on a single, plausible technological and scientific breakthrough: “mind uploading,” i.e., the possibility of copying the brain/mind of a human and running the resulting copy on computer hardware. This scenario does not assume a vast improvement in our understanding of neuroanatomy (after all, the mind is merely copied and its behaviour simulated, not understood), nor does it posit artificial general intelligence.

All Hanson assumes is copy-and-transfer. (Also, the emulated mind, or “em,” is cheap in terms of hardware; cheaper than the original mind-in-homo-sapiens-body. It follows that minds can be copied.)

From this assumption, Hanson leverages his considerable command of the disciplines of economics, other social sciences, cultural studies, anthropology, physics, computer science, &c, to arrive at a very solid and internally consistent description of how the “em world” would look. And it’s not what you’d expect. Em world is populated by millions of copies of rather few archetypes, selected for intelligence, diligence, honesty, social skills, and with a Protestant work ethic that would make Max Weber sigh. Ems are piss-poor, living in a Malthusian dystopia just above subsistence levels, yet quite happy. Most of them spend their time in virtual reality, balancing the opportunity cost of not working with the quality of the simulated leisure environment. Em society is tribal, moralising, and runs at different speeds—you speed up to visit your much-more-efficient-boss, whom it makes sense to run 10 times faster despite the cost, but you also speed up for your vacation, so you don’t miss much work.

Hanson infers how ems mate, what government they might prefer, what swear words they use, and how their cities are cooled. There are sections on adiabatic computing and what stories ems enjoy. Much of it is surprising, and all of it makes sense.

The presentation is magisterial and extremely dense. This book can be enjoyed for its description of what we know about humans today alone:

Humans who attend directly to vivid cases [of inequality] are capable of great empathy with inequality losers. They are also capable of great compassion and even a desire to help. However, we humans are also quite capable of avoiding contact and exposure that might produce such compassion, and of numbing ourselves to the plight of losers about whom it would be inconvenient to feel empathy. So rich people avoid visiting poor neighborhoods and nations, attractive people avoid socializing with the ugly, and pretty young women become numb to the losses of the men they reject.


The tone is uniformly dry and extremely funny because of its callous monotone. Here’s another example:


[E]ms probably continue to suffer periodically from greatly debilitating mental conditions such as depression, love-sickness, or hobby obsession. In a competitive em economy, such conditions may often result in ending that copy and reviving a copy archived before the condition appeared.


So: better read it now. The book is quite engrossing, and in an em world you might be disinclined to allow yourself such an indulgence. Faced with a book like Hanson’s, a diligent em ought to revert to the last save point.
Profile Image for Bogdan Balostin.
Author 5 books9 followers
January 28, 2021
A history of the future.

First, let's get this out of the way. This is not a novel. This is not an engaging non-fiction book. This is a chronicle of a possible future written in dry academic language. There are no "click baits". There are no fear-mongering stories. There are no uplifting wondrous stories of the future. This book is emotionless.

Why should you read it? Well, not everyone should read it. But people with the power to decide our future should. Historians should, too. It's applied social science to forecasting the consequences of technology. And we need more books like this. They will clearly lose their relevance fast, like any scientific paper proved wrong. But they will guide our thoughts and make us think of the future we want and the future that is possible.

The past is behind us but every choice we take now has a consequence in the future. Political and economic policies, funding and banning of research, all should be based on powerful considerations, that not only take into account the short term profit. We owe it to future generations and maybe we owe it to ourselves if the long-term profits affect us, in one way or another.

This book is about emulations or mind-uploading. It's not a science fiction novel, but predictions based on statistics and current trends in social science. A forecast is just a forecast. It may be totally wrong and there are already critics that try to prove what Robin Hanson is totally wrong as of the moment of writing, but that's okay. If he wouldn't have written the book. the critics would be silent and the conversation would not exist. To create conversations we need to think about the future in dry, academic, provable ways... which can serve as inspiration for science fiction writers, who can then write awesome stories that don't sound silly. And that is great.
3 reviews
February 1, 2018
This was a pretty mindblowing book. I've thought more than most about the distant future, robot uprisings, colonizing other planets, entering a Matrix or San Junipero-type simulation, etc., to the extent that I'm even signed up for cryonics to increase my chances of being there. But I realize now I had not thought about the real implications of having the technology to scan brains and emulate them on computer hardware. Robin Hanson has. He lays out a baseline, "least weird" scenario of what the world will be like when we can copy our brains into computers, and then potentially have more than one copy running at a time. As promising as AI may be, I've long thought the first truly intelligent computers will be emulations of existing human brains that were scanned, and that this technology will be possible by the end of this century. But the amount of change that would happen in the world immediately after that would be staggering - as big of a shift as from going from a hunter-gatherer society to a farming one, or a farming one to an industrial one. If you're old enough to be reading this review right now (and you're not signed up for cryonics) you probably personally won't see this world Hanson describes, but your children or grandchildren just might. If you're curious at all about what kind of world they'll live in - a world in which flesh-and-blood humans are looked at the way we look at the few remaining hunter-gatherer societies today - you need to read this book.
June 19, 2016
The Age of EM is a wonderful exercise in "world Building", that is science fiction without the plot and characters. I particularly recommend the book if, like me, you often get frustrated with the superficiality of the background against which, otherwise, good futuristic stories take place (implausible dystopian political institutions, technological incoherence etc..). Robin Hanson, an economics professor known for his eclecticism (he trained in physics, worked as an AI researcher, studied many social sciences etc..) assumes that individual human brain emulations (ems) will become possible within a century or so and goes on to describe what a world dominated by ems would look like. He does so in great details (institutions, economics, culture, love life etc.) drawing on most accepted, consensus engineering and social sciences theories. This makes the description of this world perfectly coherent, with each conclusion easily traceable to its premise. You will enjoy the book most if you don't get too hanged up on whether or when brain uploading will be possible or if other scenarios are possible... or even whether you like that world or not.
Profile Image for Thomas.
496 reviews7 followers
December 31, 2016
I was going to rate this book a 3/5. However, for sheer idea/concept per page value it is easily a 5/5. The writing may be dry and fairly methodical (possibly a positive?) and there are definitely some gripes with the methods (for example Hanson cites a statistically insignificant study on marriage at one point) but overall this book certainly delivers. It isn't so much about conceptualising ONE future as the most likely, but more about conceptualising ONE PLAUSIBLE future, with the main intent being practice of mind and looking at how different future humans. Hanson is EXTREMELY CLEAR that this world view is not meant to be taken as verbatim, nor is he 100% positive that his imaginings will come to pass. He has plenty of sections discussing alternatives and alterations to his timescale. But as I said if you want a book about futurism that will give you the most bang for buck, this is without a doubt the best book you could buy.
Profile Image for Matthew.
8 reviews2 followers
May 30, 2016
Robin's book creates a unique genre that anyone who is interested in the trajectory of humanity in the next century should embrace. Hanson makes the point that far more people are historians that futurists. Futurism has been left to Sci-Fi and is often compelling but lacking in either economic or scientific rigor. Hanson actually is a good historian in the book and extrapolates a future that is hinted at by Sci-fi but explained in rational way in this book. He may be right or he may be wrong. It may be a horrifying future to you or an inevitable one where a value judgement is less easy to make. There are also things about an EM dominated world that may seem attrative in our hyper productive world. There may be reasons why there are more historians than futurists, but if we care about our descendants as much as our ancestors this book is as provocative and exciting as they get.
Profile Image for Jon Norimann.
454 reviews8 followers
September 15, 2018
The Age of Em discusses how a brain uploaded to a computer will be living life. It also discusses how internet cities of such brains will change the rest of the world and various other related issues.

Social science rather than computer science is the angle of attack, although tech issues are covered aswell. The technology assumed is highly speculative although just within what one can reasonably hope gets available in the next 100 years or so. Inferring consequences of such a technology is then of course doubly speculative but none the less very interesting.

Hanson wrote this book in 2016 and as of 2018 it is a refreshing and fascinating look at one possible new tech and its consequences. However read it fast as developments move fast in this area and may render the book outdated in not many years.
25 reviews3 followers
February 2, 2017
A brave attempt at predicting the future from a former professor of mine. This book imagines the world after brain emmulation technology has arrived. That is, a technology that allows a human´s brain to be copied, and for that em to do thinking and living on its own. A crazy topic, but only one that can be understood by picking up the book.

At times technical, academic and repetitive it can be hard to read, but anyone who finishes is left with a great reward: a serious study of our future. And, as Hanson points out, studying the future is more important than studying the past because we can control the future.
Profile Image for Hamish.
404 reviews29 followers
October 23, 2019
Very, very interesting. A compelling (epistemically compelling, rather than morally compelling) alternative future to the AI-dominated one which I've habitually been thinking in terms of.

It's really inspired me to be a better economic unit, who works hard at useful jobs and is agreeable/industrious/low-neuroticism/religious/intelligence/rational/whatever-else-correlates-with-productivity so that I can maximise my chances of getting uploaded to the em world and becoming a major clan.
Profile Image for William Kiely.
21 reviews3 followers
December 31, 2019
I appreciate how this book tries to accurately forecast the future. I like how Robin acts as a historian of the future to predict how the world may actually look given certain assumptions. And I like how Robin concretely states his confidence levels that the predictions made in the book will bear out in reality. I'd love to see more thoughtful people explicitly write out their thoughts on the future in this manner.
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