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It’s not every day that I check my office mailbox and, amid the junk brochures, find 500 pages on the biggest questions facing civilization—all of them, basically—by possibly the single person on earth most qualified to tackle those questions.  That’s what happened when, on a trip back to Austin from my sabbatical, I found a review copy of Steven Pinker’s Enlightenment Now: The Case for Reason, Science, Humanism, and Progress.

I met with Steve while he was writing this book, and fielded his probing questions about the relationships among the concepts of information, entropy, randomness, Kolmogorov complexity, and coarse graining, in a way that might have affected a few paragraphs in Chapter 2.  I’m proud to be thanked in the preface—well, as “Scott Aronson.”  I have a lot of praise for the book, but let’s start with this: the omission of the second “a” from my surname was the worst factual error that I found.

If you’ve read anything else by Pinker, then you more-or-less know what to expect: an intellectual buffet that’s pure joy to devour, even if many of the dishes are ones you’ve tasted before.  For me, the writing alone is worth the admission price: Pinker is, among many other distinctions, the English language’s master of the comma-separated list.  I can see why Bill Gates recently called Enlightenment Now his “new favorite book of all time“—displacing his previous favorite, Pinker’s earlier book The Better Angels of Our Nature.  If you’ve read Better Angels, to which Enlightenment Now functions as a sort of sequel, then you know even more specifically what to expect: a saturation bombing of line graphs showing you how, despite the headlines, the world has been getting better in almost every imaginable way—graphs so thorough that they’ll eventually drag the most dedicated pessimist, kicking and screaming, into sharing Pinker’s sunny disposition, at least temporarily (but more about that later).

The other book to which Enlightenment Now bears comparison is David Deutsch’s The Beginning of Infinity.  The book opens with one of Deutsch’s maxims—“Everything that is not forbidden by laws of nature is achievable, given the right knowledge”—and Deutsch’s influence can be seen throughout Pinker’s new work, as when Pinker repeats the Deutschian mantra that “problems are solvable.”  Certainly Deutsch and Pinker have a huge amount in common: classical liberalism, admiration for the Enlightenment as perhaps the best thing that ever happened to the human species, and barely-perturbable optimism.

Pinker’s stated aim is to make an updated case for the Enlightenment—and specifically, for the historically unprecedented “ratchet of progress” that humankind has been on for the last few hundred years—using the language and concepts of the 21^st century.  Some of his chapter titles give a sense of the scope of the undertaking:

• Life
• Health
• Wealth
• Inequality
• The Environment
• Peace
• Safety
• Terrorism
• Equal Rights
• Knowledge
• Happiness
• Reason
• Science

When I read these chapter titles aloud to my wife, she laughed, as if to say: how could anyone have the audacity to write a book on just one of these enormities, let alone all of them?  But you can almost hear the gears turning in Pinker’s head as he decided to do it: well, someone ought to take stock in a single volume of where the human race is and where it’s going.  And if, with the rise of thuggish autocrats all over the world, the principles of modernity laid down by Locke, Spinoza, Kant, Jefferson, Hamilton, and Mill are under attack, then someone ought to rise to those principles’ unironic defense.  And if no one else will do it, it might as well be me!  If that’s how Pinker thought, then I agree: it might as well have been him.

I also think Pinker is correct that Enlightenment values are not so anodyne that they don’t need a defense.  Indeed, nothing demonstrates the case for Pinker’s book, the non-obviousness of his thesis, more clearly than the vitriolic reviews the book has been getting in literary venues.  Take this, for example, from John Gray in The New Statesman: “Steven Pinker’s embarrassing new book is a feeble sermon for rattled liberals.”

Pinker is an ardent enthusiast for free-market capitalism, which he believes produced most of the advance in living standards over the past few centuries. Unlike [Herbert Spencer, the founder of Social Darwinism], he seems ready to accept that some provision should be made for those who have been left behind. Why he makes this concession is unclear. Nothing is said about human kindness, or fairness, in his formula. Indeed, the logic of his dictum points the other way.

Many early-20th-century Enlightenment thinkers supported eugenic policies because they believed “improving the quality of the population” – weeding out human beings they deemed unproductive or undesirable – would accelerate the course of human evolution…

Exponents of scientism in the past have used it to promote Fabian socialism, Marxism-Leninism, Nazism and more interventionist varieties of liberalism. In doing so, they were invoking the authority of science to legitimise the values of their time and place. Deploying his cod-scientific formula to bolster market liberalism, Pinker does the same.

You see, when Pinker says he supports Enlightenment norms of reason and humanism, he really means to say that he supports unbridled capitalism and possibly even eugenics.  As I read this sort of critique, the hair stands on my neck, because the basic technique of hostile mistranslation is so familiar to me.  It’s the technique that once took a comment in which I pled for shy nerdy males and feminist women to try to understand each other’s suffering, as both navigate a mating market unlike anything in previous human experience—and somehow managed to come away with the take-home message, “so this entitled techbro wants to return to a past when society would just grant him a female sex slave.”

I’ve noticed that everything Pinker writes bears the scars of the hostile mistranslation tactic.  Scarcely does he say anything before he turns around and says, “and here’s what I’m not saying”—and then proceeds to ward off five different misreadings so wild they wouldn’t have occurred to me, but then if you read Leon Wieseltier or John Gray or his other critics, there the misreadings are, trotted out triumphantly; it doesn’t even matter how much time Pinker spent trying to prevent them.

OK, but what of the truth or falsehood of Pinker’s central claims?

I share Pinker’s sense that the Enlightenment may be the best thing that ever happened in our species’ sorry history.  I agree with his facts, and with his interpretations of the facts.  We rarely pause to consider just how astounding it is—how astounding it would be to anyone who lived before modernity—that child mortality, hunger, and disease have plunged as far as they have, and we show colossal ingratitude toward the scientists and inventors and reformers who made it possible.  (Pinker lists the following medical researchers and public health crusaders as having saved more than 100 million lives each: Karl Landsteiner, Abel Wolman, Linn Enslow, William Foege, Maurice Hilleman, John Enders.  How many of them had you heard of?  I’d heard of none.)  This is, just as Pinker says, “the greatest story seldom told.”

Beyond the facts, I almost always share Pinker’s moral intuitions and policy preferences.  He’s right that, whether we’re discussing nuclear power, terrorism, or GMOs, going on gut feelings like disgust and anger, or on vivid and memorable incidents, is a terrible way to run a civilization.  Instead we constantly need to count: how many would be helped by this course of action, how many would be harmed?  As Pinker points out, that doesn’t mean we need to become thoroughgoing utilitarians, and start fretting about whether the microscopic proto-suffering of a bacterium, multiplied by the 10³¹ bacteria that there are, outweighs every human concern.  It just means that we should heed the utilitarian impulse to quantify way more than is normally done—at the least, in every case where we’ve already implicitly accepted the underlying values, but might be off by orders of magnitude in guessing what they imply about our choices.

The one aspect of Pinker’s worldview that I don’t share—and it’s a central one—is his optimism.  My philosophical temperament, you might say, is closer to that of Rebecca Newberger Goldstein, the brilliant novelist and philosopher (and Pinker’s wife), who titled a lecture given shortly after Trump’s election “Plato’s Despair.”

Somehow, I look at the world from more-or-less the same vantage point as Pinker, yet am terrified rather than hopeful.  I’m depressed that Enlightenment values have made it so far, and yet there’s an excellent chance (it seems to me) that it will be for naught, as civilization slides back into authoritarianism, and climate change and deforestation and ocean acidification make the one known planet fit for human habitation increasingly unlivable.

I’m even depressed that Pinker’s book has gotten such hostile reviews.  I’m depressed, more broadly, that for centuries, the Enlightenment has been met by its beneficiaries with such colossal incomprehension and ingratitude.  Save 300 million people from smallpox, and you can expect in return a lecture about your naïve and arrogant scientistic reductionism.  Or, electronically connect billions of people to each other and to the world’s knowledge, in a way beyond the imaginings of science fiction half a century ago, and people will use the new medium to rail against the gross, basement-dwelling nerdbros who made it possible, then upvote and Like each other for their moral courage in doing so.

I’m depressed by the questions: how can a human race that reacts in that way to the gifts of modernity possibly be trusted to use those gifts responsibly?  Does it even “deserve” the gifts?

As I read Pinker, I sometimes imagined a book published in 1923 about the astonishing improvements in the condition of Europe’s Jews following their emancipation.  Such a book might argue: look, obviously past results don’t guarantee future returns; all this progress could be wiped out by some freak future event.  But for that to happen, an insane number of things would need to go wrong simultaneously: not just one European country but pretty much all of them would need to be taken over by antisemitic lunatics who were somehow also hyper-competent, and who wouldn’t just harass a few Jews here and there until the lunatics lost power, but would systematically hunt down and exterminate all of them with an efficiency the world had never before seen.  Also, for some reason the Jews would need to be unable to escape to Palestine or the US or anywhere else.  So the sane, sober prediction is that things will just continue to improve, of course with occasional hiccups (but problems are solvable).

Or I thought back to just a few years ago, to the wise people who explained that, sure, for the United States to fall under the control of a racist megalomaniac like Trump would be a catastrophe beyond imagining.  Were such a comic-book absurdity realized, there’d be no point even discussing “how to get democracy back on track”; it would already have suffered its extinction-level event.  But the good news is that it will never happen, because the voters won’t allow it: a white nationalist authoritarian could never even get nominated, and if he did, he’d lose in a landslide.  What did Pat Buchanan get, less than 1% of the vote?

I don’t believe in a traditional God, but if I did, the God who I’d believe in is one who’s constantly tipping the scales of fate toward horribleness—a God who regularly causes catastrophes to happen, even when all the rational signs point toward their not happening—basically, the God who I blogged about here.  The one positive thing to be said about my God is that, unlike the just and merciful kind, I find that mine rarely lets me down.

Pinker is not blind.  Again and again, he acknowledges the depths of human evil and idiocy, the forces that even now look to many of us like they’re leaping up at Pinker’s exponential improvement curves with bared fangs.  It’s just that each time, he recommends putting an optimistic spin on the situation, because what’s the alternative?  Just to get all, like, depressed?  That would be unproductive!  As Deutsch says, problems will always arise, but problems are solvable, so let’s focus on what it would take to solve them, and on the hopeful signs that they’re already being solved.

With climate change, Pinker gives an eloquent account of the enormity of the crisis, echoing the mainstream scientific consensus in almost every particular.  But he cautions that, if we tell people this is plausibly the end of civilization, they’ll just get fatalistic and paralyzed, so it’s better to talk about solutions.  He recommends an aggressive program of carbon pricing, carbon capture and storage, nuclear power, research into new technologies, and possibly geoengineering, guided by strong international cooperation—all things I’d recommend as well.  OK, but what are the indications that anything even close to what’s needed will get done?  The right time to get started, it seems to me, was over 40 years ago.  Since then, the political forces that now control the world’s largest economy have spiralled into ever more vitriolic denial, the more urgent the crisis has gotten and the more irrefutable the evidence.  Pinker writes:

“We cannot be complacently optimistic about climate change, but we can be conditionally optimistic.  We have some practicable ways to prevent the harms and we have the means to learn more.  Problems are solvable.  That does not mean that they will solve themselves, but it does mean that we can solve them if we sustain the benevolent forces of modernity that have allowed us to solve problems so far…” (p. 154-155)

I have no doubt that conditional optimism is a useful stance to adopt, in this case as in many others.  The trouble, for me, is the gap between the usefulness of a view and its probable truth—a gap that Pinker would be quick to remind me about in other contexts.  Even if a placebo works for those who believe in it, how do you make yourself believe in what you understand to be a placebo?  Even if all it would take, for the inmates to escape a prison, is simultaneous optimism that they’ll succeed if they work together—still, how can an individual inmate be optimistic, if he sees that the others aren’t, and rationally concludes that dying in prison is his probable fate?  For me, the very thought of the earth gone desolate—its remaining land barely habitable, its oceans a sewer, its radio beacons to other worlds fallen silent—all for want of ability to coordinate a game-theoretic equilibrium, just depresses me even more.

Likewise with thermonuclear war: Pinker knows, of course, that even if there were “only” an 0.5% chance of one per year, multiplied across the decades of the nuclear era that’s enormously, catastrophically too high, and there have already been too many close calls.  But look on the bright side: the US and Russia have already reduced their arsenals dramatically from their Cold War highs.  There’d be every reason for optimism about continued progress, if we weren’t in this freak branch of the wavefunction where the US and Russia (not to mention North Korea and other nuclear states) were now controlled by authoritarian strongmen.

With Trump—for how could anyone avoid him in a book like this?—Pinker spends several pages reviewing the damage he’s inflicted on democratic norms, the international order, the environment, and the ideal of truth itself:

“Trump’s barefaced assertion of canards that can instantly be debunked … shows that he sees public discourse not as a means of finding common ground based on objective reality but as a weapon with which to project dominance and humiliate rivals” (p. 336).

Pinker then writes a sentence that made me smile ruefully: “Not even a congenital optimist can see a pony in this Christmas stocking” (p. 337).  Again, though, Pinker looks at poll data suggesting that Trump and the world’s other resurgent quasi-fascists are not the wave of the future, but the desperate rearguard actions of a dwindling and aging minority that feels itself increasingly marginalized by the modern world (and accurately so).  The trouble is, Nazism could also be seen as “just” a desperate, failed attempt to turn back the ratchet of cosmopolitanism and moral progress, by people who viscerally understood that time and history were against them.  Yet even though Nazism ultimately lost (which was far from inevitable, I think), the damage it inflicted on its way out was enough, you might say, to vindicate the shrillest pessimist of the 1930s.

Then there’s the matter of takeover by superintelligent AI.  I’ve now spent years hanging around communities where it’s widely accepted that “AI value alignment” is the most pressing problem facing humanity.  I strongly disagree with this view—but on reflection, not because I don’t think AI could be a threat; only because I think other, more prosaic things are much more imminent threats!  I feel the urge to invent a new, 21^st-century Yiddish-style proverb: “oy, that we should only survive so long to see the AI-bots become our worst problem!”

Pinker’s view is different: he’s dismissive of the fear (even putting it in the context of the Y2K bug, and people marching around sidewalks with sandwich boards that say “REPENT”), and thinks the AI-risk folks are simply making elementary mistakes about the nature of intelligence.  Pinker’s arguments are as follows: first, intelligence is not some magic, all-purpose pixie dust, which humans have more of than animals, and which a hypothetical future AI would have more of than humans.  Instead, the brain is a bundle of special-purpose modules that evolved for particular reasons, so “the concept [of artificial general intelligence] is barely coherent” (p. 298).  Second, it’s only humans’ specific history that causes them to think immediately about conquering and taking over, as goals to which superintelligence would be applied.  An AI could have different motivations entirely—and it will, if its programmers have any sense.  Third, any AI would be constrained by the resource limits of the physical world.  For example, just because an AI hatched a brilliant plan to recursively improve itself, doesn’t mean it could execute that plan without (say) building a new microchip fab, acquiring the necessary raw materials, and procuring the cooperation of humans.  Fourth, it’s absurd to imagine a superintelligence converting the universe into paperclips because of some simple programming flaw or overliteral interpretation of human commands, since understanding nuances is what intelligence is all about:

“The ability to choose an action that best satisfies conflicting goals is not an add-on to intelligence that engineers might slap themselves in the forehead for forgetting to install; it is intelligence.  So is the ability to interpret the intentions of a language user in context” (p. 300).

I’ll leave it to those who’ve spent more time thinking about these issues to examine these arguments in detail (in the comments of this post, if they like).  But let me indicate briefly why I don’t think they fare too well under scrutiny.

For one thing, notice that the fourth argument is in fundamental tension with the first and second.  If intelligence is not an all-purpose elixir but a bundle of special-purpose tools, and if those tools can be wholly uncoupled from motivation, then why couldn’t we easily get vast intelligence expended toward goals that looked insane from our perspective?  Have humans never been known to put great intelligence in the service of ends that strike many of us as base, evil, simpleminded, or bizarre?  Consider the phrase often applied to men: “thinking with their dicks.”  Is there any sub-Einsteinian upper bound on the intelligence of the men who’ve been guilty of that?

Second, while it seems clear that there are many special-purpose mental modules—the hunting instincts of a cat, the mating calls of a bird, the pincer-grasping or language-acquisition skills of a human—it seems equally clear that there is some such thing as “general problem-solving ability,” which Newton had more of than Roofus McDoofus, and which even Roofus has more of than a chicken.  But whatever we take that ability to consist of, and whether we measure it by a scalar or a vector, it’s hard to imagine that Newton was anywhere near whatever limits on it are imposed by physics.  His brain was subject to all sorts of archaic evolutionary constraints, from the width of the birth canal to the amount of food available in the ancestral environment, and possibly also to diminishing returns on intelligence in humans’ social environment (Newton did, after all, die a virgin).  But if so, then given the impact that Newton, and others near the ceiling of known human problem-solving ability, managed to achieve even with their biology-constrained brains, how could we possibly see the prospect of removing those constraints as just a narrow technological matter, like building a faster calculator or a more precise clock?

Third, the argument about intelligence being constrained by physical limits would seem to work equally well for a mammoth or cheetah scoping out the early hominids.  The mammoth might say: yes, these funny new hairless apes are smarter than me, but intelligence is just one factor among many, and often not the decisive one.  I’m much bigger and stronger, and the cheetah is faster.  (If the mammoth did say that, it would be an unusually smart mammoth as well, but never mind.)  Of course we know what happened: from wild animals’ perspective, the arrival of humans really was a catastrophic singularity, comparable to the Chicxulub asteroid (and far from over), albeit one that took between 10⁴ and 10⁶ years depending on when we start the clock.  Over the short term, the optimistic mammoths would be right: pure, disembodied intelligence can’t just magically transform itself into spears and poisoned arrows that render you extinct.  Over the long term, the most paranoid mammoth on the tundra couldn’t imagine the half of what the new “superintelligence” would do.

Finally, any argument that relies on human programmers choosing not to build an AI with destructive potential, has to contend with the fact that humans did invent, among other things, nuclear weapons—and moreover, for what seemed like morally impeccable reasons at the time.  And a dangerous AI would be a lot harder to keep from proliferating, since it would consist of copyable code.  And it would only take one.  You could, of course, imagine building a good AI to neutralize the bad AIs, but by that point there’s not much daylight left between you and the AI-risk people.

As you’ve probably gathered, I’m a worrywart by temperament (and, I like to think, experience), and I’ve now spent a good deal of space on my disagreements with Pinker that flow from that.  But the funny part is, even though I consistently see clouds where he sees sunshine, we’re otherwise looking at much the same scene, and our shared view also makes us want the same things for the world.  I find myself in overwhelming, nontrivial agreement with Pinker about the value of science, reason, humanism, and Enlightenment; about who and what deserves credit for the stunning progress humans have made; about which tendencies of civilization to nurture and which to recoil in horror from; about how to think and write about any of those questions; and about a huge number of more specific issues.

So my advice is this: buy Pinker’s book and read it.  Then work for a future where the book’s optimism is justified.

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A long post is brewing (breaking my month-long silence), but as I was working on it, the sad news arrived that Stephen Hawking passed away. There’s little I can add to the tributes that poured in from around the world: like chocolate or pizza, Hawking was beloved everywhere and actually deserved to be. Like, probably, millions of other nerds of my generation, I read A Brief History of Time as a kid and was inspired by it (though I remember being confused back then about the operational meaning of imaginary time, and am still confused about it almost 30 years later).  In terms of a scientist capturing the public imagination, through a combination of genuine conceptual breakthroughs, an enthralling personal story, an instantly recognizable countenance, and oracular pronouncements on issues of the day, the only one in the same league was Einstein. I didn’t agree with all of Hawking’s pronouncements, but the quibbles paled beside the enormous areas of agreement.  Hawking was a force for good in the world, and for the values of science, reason, and Enlightenment (to anticipate the subject of my next post).

I’m sorry that I never really met Hawking, though I did participate in two conferences that he also attended, and got to watch him slowly form sentences on his computer. At one conference in 2011, he attended my talk—this one—and I was told by mutual acquaintances that he liked it.  That meant more to me than it probably should have: who cares if some random commenters on YouTube dissed your talk, if the Hawk-Man himself approved?

As for Hawking’s talks—well, there’s a reason why they filled giant auditoriums all over the world.  Any of us in the business of science popularization would do well to study them and take lessons.

If you want a real obituary of Hawking, by someone who knew him well—one that, moreover, actually explains his main scientific contributions (including the singularity theorems, Hawking radiation, and the no-boundary proposal)—you won’t do any better than this by Roger Penrose. Also don’t miss this remembrance in Time by Hawking’s friend and betting partner, and friend-of-the-blog, John Preskill. (Added: and this by Sean Carroll.)

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Various people pointed me to a Washington Post piece by Vivek Wadhwa, entitled “Quantum computers may be more of an immiment threat than AI.”  I know I’m late to the party, but in the spirit of Pete Wells’ famous New York Times “review” of Guy Fieri’s now-closed Times Square restaurant, I have a few questions that have been gnawing at me:

Mr. Wadhwa, when you decided to use the Traveling Salesman Problem as your go-to example of a problem that quantum computers can solve quickly, did the thought ever cross your mind that maybe you should look this stuff up first—let’s say, on Wikipedia?  Or that you should email one person—just one, anywhere on the planet—who works in quantum algorithms?

When you wrote of the Traveling Salesman Problem that “[i]t would take a laptop computer 1,000 years to compute the most efficient route between 22 cities”—how confident are you about that?  Willing to bet your house?  Your car?  How much would it blow your mind if I told you that a standard laptop, running a halfway decent algorithm, could handle 22 cities in a fraction of a second?

When you explained that quantum computing is “equivalent to opening a combination lock by trying every possible number and sequence simultaneously,” where did this knowledge come from?  Did it come from the same source you consulted before you pronounced the death of Bitcoin … in January 2016?

Had you wanted to consult someone who knew the first thing about quantum computing, the subject of your column, would you have been able to use a search engine to find one?  Or would you have simply found another “expert,” in the consulting or think-tank worlds, who “knew” the same things about quantum computing that you do?

Incidentally, when you wrote that quantum computing “could pose a greater burden on businesses than the Y2K computer bug did toward the end of the ’90s,” were you trying to communicate how large the burden might be?

And when you wrote that

[T]here is substantial progress in the development of algorithms that are “quantum safe.” One promising field is matrix multiplication, which takes advantage of the techniques that allow quantum computers to be able to analyze so much information.

—were you generating random text using one of those Markov chain programs?  If not, then what were you referring to?

Would you agree that the Washington Post has been a leader in investigative journalism exposing Trump’s malfeasance?  Do you, like me, consider them one of the most important venues on earth for people to be able to trust right now?  How does it happen that the Washington Post publishes a quantum computing piece filled with errors that would embarrass a high-school student doing a term project (and we won’t even count the reference to Stephen “Hawkings”—that’s a freebie)?

Were the fact-checkers home with the flu?  Did they give your column a pass simply because it was “perspective” rather than news?  Or did they trust you as a widely-published technology expert?  How does one become such an expert, anyway?

Thanks!

Update (Feb. 21): For casual readers, Vivek Wadhwa quickly came into the comments section to try to defend himself—before leaving in a huff as a chorus of commenters tried to explain why he was wrong. As far as I know, he has not posted any corrections to his Washington Post piece. Wadhwa’s central defense was that he was simply repeating what Michelle Simmons, a noted quantum computing experimentalist in Australia, said in various talks in YouTube—which turns out to be largely true (though Wadhwa said explicitly that quantum computers could efficiently solve TSP, while Simmons mostly left this as an unstated implication). As a result, while Wadhwa should obviously have followed the journalistic practice of checking incredible-sounding claims—on Wikipedia if nowhere else!—before repeating them in the Washington Post, I now feel that Simmons shares in the responsibility for this. As John Preskill tweeted, an excellent lesson to draw from this affair is that everyone in our field needs to be careful to say things that are true when speaking to the public.

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1. I was extremely sorry to learn about the loss of Joe Polchinski, a few days ago, to brain cancer.  Joe was a leading string theorist, one of the four co-discoverers of the AMPS firewall paradox, and one of the major figures in the Simons It from Qubit collaboration that I’ve been happy to be part of since its inception.  I regret that I didn’t get to know Joe as well as I should have, but he was kind to me in all of our interactions.  He’ll be missed by all who knew him.
2. Edge has posted what will apparently be its final Annual Edge Question: “What is the last question?”  They asked people to submit just a single, one sentence question “for which they’ll be remembered,” with no further explanation or elaboration.  You can read mine, which not surprisingly is alphabetically the first.  I tried to devise a single question that gestured toward the P vs. NP problem, and the ultimate physical limits of computation, and the prospects for superintelligent AI, and the enormity of what could be Platonically lying in wait for us within finite but exponentially search spaces, and the eternal nerd’s conundrum, of the ability to get the right answers to clearly-stated questions being so ineffectual in the actual world.  I’m not thrilled with the result, but reading through the other questions makes it clear just how challenging it is to ask something that doesn’t boil down to: “When will the rest of the world recognize the importance of my research topic?”
3. I’m now reaping the fruits of my decision to take a year-long sabbatical from talking to journalists.  Ariel Bleicher, a writer for Quanta magazine, asked to interview me for an article she was writing about the difficulty of establishing quantum supremacy.  I demurred, mentioning my sabbatical, and pointed her to others she could ask instead.  Well, last week the article came out, and while much of it is quite good, it opens with an extended presentation of a forehead-bangingly wrong claim by Cristian Calude: namely, that the Deutsch-Jozsa problem (i.e. computing the parity of two bits) can be solved with one query even by a classical algorithm, so that (in effect) one of the central examples used in introductory quantum computing courses is a lie.  This claim is based on a 2006 paper wherein, with all the benefits of theft over honest toil, Calude changes the query model so that you can evaluate not just the original oracle function f, but an extension of f to the complex numbers (!).  Apparently Calude justifies this by saying that Deutsch also changed the problem, by allowing it to be solved with a quantum computer, so he gets to change the problem as well.  The difference, of course, is that the quantum query complexity model is justified by its relevance for quantum algorithms, and (ultimately) by quantum mechanics being true of our world.  Calude’s model, by contrast, is (as far as I can tell) pulled out of thin air and justified by nothing.  Anyway, I regard this incident as entirely, 100% my fault, and 0% Ariel’s.  How was she to know that, while there are hundreds of knowledgeable quantum computing experts to interview, almost all of them are nice and polite?  Anyway, this has led me to a revised policy: while I’ll still decline interviews, news organizations should feel free to run completed quantum computing pieces by me for quick fact checks.

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I’ve been way too distracted by actual research lately from my primary career as a nerd blogger—that’s what happens when you’re on sabbatical.  But now I’m sick, and in no condition to be thinking about research.  And this morning, in a thread that had turned to my views on the interpretation of quantum mechanics called “QBism,” regular commenter Atreat asked me the following pointed question:

Scott, what is your preferred interpretation of QM? I don’t think I’ve ever seen you put your cards on the table and lay out clearly what interpretation(s) you think are closest to the truth. I don’t think your ghost paper qualifies as an answer, BTW. I’ve heard you say you have deep skepticism about objective collapse theories and yet these would seemingly be right up your philosophical alley so to speak. If you had to bet on which interpretation was closest to the truth, which one would you go with?

Many people have asked me some variant of the same thing.  As it happens, I’d been toying since the summer with a huge post about my views on each major interpretation, but I never quite got it into a form I wanted.  By contrast, it took me only an hour to write out a reply to Atreat, and in the age of social media and attention spans measured in attoseconds, many readers will probably prefer that short reply to the huge post anyway.  So then I figured, why not promote it to a full post and be done with it?  So without further ado:

Dear Atreat,

It’s no coincidence that you haven’t seen me put my cards on the table with a favored interpretation of QM!

There are interpretations (like the “transactional interpretation”) that make no sense whatsoever to me.

There are “interpretations” like dynamical collapse that aren’t interpretations at all, but proposals for new physical theories.  By all means, let’s test QM on larger and larger systems, among other reasons because it could tell us that some such theory is true or—vastly more likely, I think—place new limits on it! (People are trying.)

Then there’s the deBroglie-Bohm theory, which does lay its cards on the table in a very interesting way, by proposing a specific evolution rule for hidden variables (chosen to match the predictions of QM), but which thereby opens itself up to the charge of non-uniqueness: why that rule, as opposed to a thousand other rules that someone could write down?  And if they all lead to the same predictions, then how could anyone ever know which rule was right?

And then there are dozens of interpretations that seem to differ from one of the “main” interpretations (Many-Worlds, Copenhagen, Bohm) mostly just in the verbal patter.

As for Copenhagen, I’ve described it as “shut-up and calculate except without ever shutting up about it”!  I regard Bohr’s writings on the subject as barely comprehensible, and Copenhagen as less of an interpretation than a self-conscious anti-interpretation: a studied refusal to offer any account of the actual constituents of the world, and—most of all—an insistence that if you insist on such an account, then that just proves that you cling naïvely to a classical worldview, and haven’t grasped the enormity of the quantum revolution.

But the basic split between Many-Worlds and Copenhagen (or better: between Many-Worlds and “shut-up-and-calculate” / “QM needs no interpretation” / etc.), I regard as coming from two fundamentally different conceptions of what a scientific theory is supposed to do for you.  Is it supposed to posit an objective state for the universe, or be only a tool that you use to organize your experiences?

Also, are the ultimate equations that govern the universe “real,” while tables and chairs are “unreal” (in the sense of being no more than fuzzy approximate descriptions of certain solutions to the equations)?  Or are the tables and chairs “real,” while the equations are “unreal” (in the sense of being tools invented by humans to predict the behavior of tables and chairs and whatever else, while extraterrestrials might use other tools)?  Which level of reality do you care about / want to load with positive affect, and which level do you want to denigrate?

This is not like picking a race horse, in the sense that there might be no future discovery or event that will tell us who was closer to the truth.  I regard it as conceivable that superintelligent AIs will still argue about the interpretation of QM … or maybe that God and the angels argue about it now.

Indeed, about the only thing I can think of that might definitively settle the debate, would be the discovery of an even deeper level of description than QM—but such a discovery would “settle” the debate only by completely changing the terms of it.

I will say this, however, in favor of Many-Worlds: it’s clearly and unequivocally the best interpretation of QM, as long as we leave ourselves out of the picture!  I.e., as long as we say that the goal of physics is to give the simplest, cleanest possible mathematical description of the world that somewhere contains something that seems to correspond to observation, and we’re willing to shunt as much metaphysical weirdness as needed to those who worry themselves about details like “wait, so are we postulating the physical existence of a continuum of slightly different variants of me, or just an astronomically large finite number?” (Incidentally, Max Tegmark’s “mathematical multiverse” does even better than MWI by this standard.  Tegmark is the one waiting for you all the way at the bottom of the slippery slope of always preferring Occam’s Razor over trying to account for the specificity of the observed world.)  It’s no coincidence, I don’t think, that MWI is so popular among those who are also eliminativists about consciousness.

When I taught my undergrad Intro to Quantum Information course last spring—for which lecture notes are coming soon, by the way!—it was striking how often I needed to resort to an MWI-like way of speaking when students got confused about measurement and decoherence. (“So then we apply this unitary transformation U that entangles the system and environment, and we compute a partial trace over the environment qubits, and we see that it’s as if the system has been measured, though of course we could in principle reverse this by applying U^-1 … oh shoot, have I just conceded MWI?”)

On the other hand, when (at the TAs’ insistence) we put an optional ungraded question on the final exam that asked students their favorite interpretation of QM, we found that there was no correlation whatsoever between interpretation and final exam score—except that students who said they didn’t believe any interpretation at all, or that the question was meaningless or didn’t matter, scored noticeably higher than everyone else.

Anyway, as I said, MWI is the best interpretation if we leave ourselves out of the picture.  But you object: “OK, and what if we don’t leave ourselves out of the picture?  If we dig deep enough on the interpretation of QM, aren’t we ultimately also asking about the ‘hard problem of consciousness,’ much as some people try to deny that? So for example, what would it be like to be maintained in a coherent superposition of thinking two different thoughts A and B, and then to get measured in the |A⟩+|B⟩, |A⟩-|B⟩ basis?  Would it even be like anything?  Or is there something about our consciousness that depends on decoherence, irreversibility, full participation in the arrow of the time, not living in an enclosed little unitary box like AdS/CFT—something that we’d necessarily destroy if we tried to set up a large-scale interference experiment on our own brains, or any other conscious entities?  If so, then wouldn’t that point to a strange sort of reconciliation of Many-Worlds with Copenhagen—where as soon as we had a superposition involving different subjective experiences, for that very reason its being a superposition would be forevermore devoid of empirical consequences, and we could treat it as just a classical probability distribution?”

I’m not sure, but The Ghost in the Quantum Turing Machine will probably have to stand as my last word (or rather, last many words) on those questions for the time being.

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I saw today that Ryan Lackey generously praised my and Zach Weinersmith’s quantum computing SMBC comic on Twitter:

Somehow this SMBC comic is the best explanation of quantum computing for non-professionals that I’ve ever found

To which the venture capitalist Matthew Ocko replied, in another tweet:

Except Scott Aaronson is a surly little troll who has literally never built anything at all of meaning. He’s a professional critic of braver people.  So, no, this is not a good explanation – anymore than Jeremy Rifkin on CRISPR would be…

Now, I don’t mind if Ocko hates me, and also hates my and Zach’s comic.  What’s been bothering me is just the logic of his tweet.  Like: what did he have in his head when he wrote the word “So”?  Let’s suppose for the sake of argument that I’m a “surly little troll,” and an ax murderer besides.  How does it follow that my explanation of quantum computing wasn’t good?  To reach that stop in proposition-space, wouldn’t one still need to point to something wrong with the explanation?

But I’m certain that my inability to understand this is just another of my many failings.  In a world where Trump is president, bitcoin is valued at $11,000 when I last checked, and the attack-tweet has fully replaced the argument, it’s obvious that those of us who see a word like “so” or “because,” and start looking for the inferential step, are merely insufficiently brave.  For godsakes, I’m not even on Twitter!  I’m a sclerotic dinosaur who needs to get with the times.

But maybe I, too, could learn the art of the naked ad-hominem.  Let me try: from a Google search, we learn that Ocko is an enthusiastic investor in D-Wave.  Is it possible he’s simply upset that there’s so much excitement right now in experimental quantum computing—including “things of meaning” being built by brave people, at Google and IBM and Rigetti and IonQ and elsewhere—but that virtually none of this involves D-Wave, whose devices remain interesting from various physics and engineering standpoints, but still fail to achieve any clear quantum speedups, just as the professional critics predicted?  Is he upset that the brave system-builders who are racing finally to achieve quantum computational supremacy over the next year, are the ones who actually interacted with academic researchers (sorry: surly little trolls), and listened to what they said?  Who understood, for example, why scaling up to 50+ qubits only made a lot of sense once you had one or two qubits that at least behaved well enough in isolation—which, after years of heroic effort, many of these system-builders now do?

How’d I do?  Was there still too much argument there for the world of 2018?

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The purpose of this post is just to call everyone’s attention to a beautiful and accessible new article by John Preskill: Quantum Computing in the NISQ era and beyond.  The article is based on John’s keynote address at the recent “Q2B” (Quantum Computing for Business) conference, which I was unfortunately unable to attend.  Here’s the abstract:

Noisy Intermediate-Scale Quantum (NISQ) technology will be available in the near future. Quantum computers with 50-100 qubits may be able to perform tasks which surpass the capabilities of today’s classical digital computers, but noise in quantum gates will limit the size of quantum circuits that can be executed reliably. NISQ devices will be useful tools for exploring many-body quantum physics, and may have other useful applications, but the 100-qubit quantum computer will not change the world right away — we should regard it as a significant step toward the more powerful quantum technologies of the future. Quantum technologists should continue to strive for more accurate quantum gates and, eventually, fully fault-tolerant quantum computing.

Did you ever wish you had something even better than a clone: namely, someone who writes exactly what you would’ve wanted to write, on a topic people keep asking you to write about, but ten times better than you would’ve written it?  To all journalists and others who ask me over the coming year about the application potential for near-term quantum computers, I can now simply respond with a link.

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Happy new year, everyone!

An anonymous commenter wrote:

Scott, you seem to admire Steven Pinker, you had problems with SJW attacks for your now famous comment 171 and, if I remember well, you said you have some “heterodox” ideas that you think it’s dangerous to make public.  [Actually, I’m not sure I ever said that—indeed, if it were true, why would I say it? 🙂 –SA ]  Why aren’t you in the Heterodox Academy? Didn’t you know about it?

Heterodox Academy is an organisation of professors, adjunct professors, post-docs and graduate students who are for freedom of speech, founded by Steven Pinker, Jonathan Haidt and a few other academics, and now has over 1000 members.

https://heterodoxacademy.org

(I’m not a member, because I’m not an academic or graduate student, but I sympathize very much with their fight to protect freedom of thought.)

By coincidence, just last week I was looking at the Heterodox Academy website, and thinking about joining.  But then I got put off by the “pledge” for new members:

“I believe that university life requires that people with diverse viewpoints and perspectives encounter each other in an environment where they feel free to speak up and challenge each other. I am concerned that many academic fields and universities currently lack sufficient viewpoint diversity—particularly political diversity. I will support viewpoint diversity in my academic field, my university, my department, and my classroom.”

For some reason, I’m allergic to joining any organization that involves a pledge, even if it’s a pledge that I completely agree with.  And in this case, maybe the issue goes a bit deeper.  My central concern, with university life, is that academics share a baseline commitment to Enlightenment norms and values: e.g., to freedom of speech, reason, empiricism, and judging arguments by their merits rather than by the speaker’s identity.  These are the norms that I’d say enabled the scientific revolution, and that are still the fundamental preconditions for intellectual inquiry.

A diversity of viewpoints is often a good diagnostic for Enlightenment norms, but it’s not the central issue, and is neither necessary nor sufficient.  For example, I don’t care if academia lacks “viewpoint diversity” in the UFO, creationism, or birther debates.  Nor do I care if the spectrum of ideas that gets debated in academia is radically different from the spectrum debated in the wider society.  Indeed, I don’t even know that it’s mathematically possible to satisfy everyone on that count: for example, a representative sampling of American political opinions might strike a European, or a Bay Area resident, as bizarrely clustered in one or two corners of idea-space, and the reverse might be equally true.

More pointedly—and bear with me as I invent a bizarre hypothetical—if some sort of delusional, autocratic thug managed to take control of the United States: someone who promoted unhinged conspiracy theories; whose whole worldview were based on the overwhelming of facts, reason, reality, and even linguistic coherence by raw strength and emotion; whose every word and deed were diametrically opposed to any conceivable vision of the mission of a university—in such an extreme case, I’d hope that American academia would speak with one voice against the enveloping darkness, just as I would’ve hoped German academia would speak with one voice in 1933 (it didn’t).  When Enlightenment norms themselves are under assault, those norms are consistent with a unified response.

Having said that, I’m certainly also worried about the erosion of Enlightenment norms within academia, or specific parts of academia: the speakers shouted down rather than debated, the classrooms taken over, the dogmatic postmodernism and blank-slatism, all the stuff Jonathan Haidt reviews in this article.  This is a development for which the left, not the right, bears primary responsibility.  I view it as a huge unearned gift that the “good guys” give the “bad guys.”  It provides them endless outrage-fodder.  It stokes their paranoid fantasies while also making us look foolish.  And it lets them call us hypocrites, whose prattle about science and reason and free inquiry has been conclusively unmasked.  So if Heterodox Academy is making headway against the illiberal wing of liberalism, that does seem like something I should support, regardless of any differences in emphasis.

Readers: what do you think?  In the comments, give me your best argument for why I should or shouldn’t join Heterodox Academy.  Feel free to call my attention to anything the organization has been up to; my research has been less than comprehensive.  I’ll credit the most convincing argument(s) when I make a decision.  Like, not that it’s especially consequential either way, but if commenters here are going to argue anyway, we might as well make something actually hinge on it…

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In addition to the emails from journalists, I also get a large number of emails seeking interactions with me—a discussion of cryptocurrencies, help in planning a political campaign, whatever—that could probably be had just as well, or better, with some other reader of this blog.  So inspired by Slate Star Codex, my lodestar of blog-greatness, I’ve decided to host Shtetl-Optimized‘s first ever classifieds thread.  This is your place to post any announcement, ad, offer, proposal, etc. that you think would be of particular interest to fellow Shtetl-Optimized readers.  As usual, I reserve the right to remove anything too spammy or otherwise unsuitable (“C@$H 4 G0LD!!!”), but will generally be pretty permissive.

Oh yes: Merry Christmas to those who celebrate it, from a spot roughly equal driving distance (about an hour 20 minutes) from Nazareth and Bethlehem!

Update: OK, let me start the ball rolling, or rather the photon propagating. Reader Piotr Migdal wrote to tell me about a quantum optics puzzle game that he created. I tried it and it’s excellent, and best of all clear: unlike virtually every other “quantum game” I’ve tried, it took me only a minute to figure this one out. (Admittedly, it’s less of a quantum game than an “optics game,” in the sense that the effects it teaches about also appear with laser beams and other many-photon coherent states, which you don’t really need QM for, even though QM provides their ultimate explanation. But whatever: it’s fun!) Piotr has lots of other great stuff on his website.

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For over a decade, one of the main ways I’ve tried to advance the cause of Enlightenment has been talking to journalists writing popular articles on quantum computing (or P vs. NP, or the universe as a computer simulation, or whatever).  Because of my blog, journalists knew how to reach me, and because I’m a ham, I always agreed to be interviewed.  Well, I told myself I was doing it as my way of giving back to the field, so that my smarter colleagues would have more time for research.

Unfortunately, this task has sort of taken over my life.  It used to be once a month, then it became once a week, and by now it’s pretty much every day.  Comment on this claim by IBM, that press release by Rigetti, this embargoed Nature paper by a group in Australia.  And when you do, it would be great if you could address this itemized list of 12 questions, with more questions coming later depending on what the editor needs.

On Friday we were on a family outing, with Dana driving and me in the front passenger seat, typing out another reply to a journalist on my phone.  Because of my engrossment in my Enlightenment duties, I neglected to tell Dana where the exit was, which then made us a half hour late for a scheduled museum tour and nearly ruined the day.

So then and there, I swore an oath to my family: that from now until January 1, 2019, I will be on vacation from talking to journalists.  This is my New Years resolution, except that it starts slightly before New Years.  Exceptions can be made when and if there’s a serious claim to have achieved quantum computational supremacy, or in other special cases.  By and large, though, I’ll simply be pointing journalists to this post, as a public commitment device to help me keep my oath.

I should add that I really like almost all of the journalists I talk to, I genuinely want to help them, and I appreciate the extreme difficulty that they’re up against: of writing a quantum computing article that avoids the Exponential Parallelism Fallacy and the “n qubits = 2ⁿ bits” fallacy and passes the Minus Sign Test, yet also satisfies an editor for whom even the so-dumbed-down-you-rip-your-hair-out version was already too technical.  And things have gotten both more exciting and more confusing in the last few years, with even the experts disagreeing about what should count as a “real quantum speedup,” or how much we should expect quantum computers to help with optimization or machine learning problems.  And of course, if journalists are trying to sort this out, then they should talk to someone who knows a bit about it, and I lack the strategic false modesty to deny being such a person.  Like, someone who calls me to fact-check a quantum computing piece should be rewarded for having done something right!  Alas, these considerations are how I let talking to journalists take over my life, so I can no longer treat them as dispositive.

For journalists looking for what to do, my suggestion is to talk to literally anyone else in the field.  E.g., look at the speakers from the past 20 years of QIP conferences—pretty much any of them could answer quantum computing questions as well as I can!  I’m tempted to name one or two specific colleagues to whom everyone should direct all their inquiries for the next year, but I can’t think of anyone I hate enough.

Unrelated Update: There’s at least one striking respect in which a human baby is like a dog, cat, or other domesticated animal. Namely, these are entities for which you can look into their eyes, and wonder whether they have any awareness whatsoever of the most basic facts of their situation. E.g., do they “know” which individual person is looking at them? Whether it’s morning or night? Which room they’re currently in? And yet, as soon as it comes to the entity’s food sources, all these doubts vanish. Yes, the baby / dog / cat clearly does understand exactly which person is supposed to feed it, and at what time of day, and often even where the food is stored. Implications for the mind/body problem (mind/stomach problem?) are left as exercises for the reader.

Unrelated Update #2: As many of you have probably seen, the cruel and monstrous tax bill awaits only Twitler’s signature, but at least the PhD student tuition tax was taken out, so American higher education lives another day. So, does this mean academics’ apoplectic fears were overblown? No, because public opposition, based on widely disseminated information about what the new tax would do to higher education, probably played an important role in causing the provision to be removed. Keep up the fight.

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