Outraged about the Google diversity memo? I want you to think about it.

Chairs. [Image: Verco]

That leaked internal memo from James Damore at Google? The one that says one shouldn’t expect employees in all professions to reflect the demographics of the whole population? Well, that was a pretty dumb thing to write. But not because it’s wrong. Dumb is that Damore thought he could have a reasoned discussion about this. In the USA, out of all places.

The version of Damore’s memo that first appeared on Gizmodo missed references and images. But meanwhile, the diversity memo has its own website and it comes with links and graphics.

Damore’s strikes me as a pamphlet produced by a well-meaning, but also utterly clueless, young white man. He didn’t deserve to get fired for this. He deserved maybe a slap on the too-quickly typing fingers. But in his world, asking for discussion is apparently enough to get fired.

I don’t normally write about the underrepresentation of women in science. Reason is I don’t feel fit to represent the underrepresented. I just can’t seem to appropriately suffer in my male-dominated environment. To the extent that one can trust online personality tests, I’m an awkwardly untypical female. It’s probably unsurprising I ended up in theoretical physics.

There is also a more sinister reason I keep my mouth shut. It’s that I’m afraid of losing what little support I have among the women in science when I fall into their back.

I’ve lived in the USA for three years and for three more years in Canada. On several occasions during these years, I’ve been told that my views about women in science are “hardcore,” “controversial,” or “provocative.” Why? Because I stated the obvious: Women are different from men. On that account, I’m totally with Damore. A male-female ratio close to one is not what we should expect in all professions – and not what we should aim at either.

But the longer I keep my mouth shut, the more I think my silence is a mistake. Because it means leaving the discussion – and with it, power – to those who shout the loudest. Like CNBC. Which wants you to be “shocked” by Damore’s memo in a rather transparent attempt to produce outrage and draw clicks. Are you outraged yet?

Increasingly, media-storms like this make me worry about the impression scientists give to the coming generation. Give to kids like Damore. I’m afraid they think we’re all idiots because the saner of us don’t speak up. And when the kids think they’re oh-so-smart, they’ll produce pamphlets to reinvent the wheel.

Fact is, though, much of the data in Damore’s memo is well backed-up by research. Women indeed are, on the average, more neurotic than men. It’s not an insult, it’s a common term in psychology. Women are also, on the average, more interested in people than in things. They do, on the average, value work-life balance more, react differently to stress, compete by other rules. And so on.

I’m neither a sociologist nor psychologist, but my understanding of the literature is that these are uncontroversial findings. And not new either. Women are different from men, both by nature and by nuture, though it remains controversial just what is nurture and what is nature. But the cause is besides the point for the question of occupation: Women are different in ways that plausibly affect their choice of profession.

No, the problem with Damore’s argument isn’t the starting point, the problem is the conclusions that he jumps to.

To begin with, even I know most of Google’s work is people-centric. It’s either serving people directly, or analyzing people-data, or imagining the people-future. If you want to spend your life with things and ideas rather than people, then go into engineering or physics, but not into software-development.

That coding actually requires “female” skills was spelled out clearly by Yonatan Zunger, a former Google employee. But since I care more about physics than software-development, let me leave this aside.

The bigger mistake in Damore’s memo is one I see frequently: Assuming that job skills and performance can be deduced from differences among demographic groups. This just isn’t so. I believe for example if it wasn’t for biases and unequal opportunities, then the higher ranks in science and politics would be dominated by women. Hence, aiming at a 50-50 representation gives men an unfair advantage. I challenge you to provide any evidence to the contrary.

I’m not remotely surprised, however, that Damore naturally assumes the differences between typically female and male traits mean that men are more skilled. That’s the bias he thinks he doesn’t have. And, yeah, I’m likewise biased in favor of women. Guess that makes us even then.

The biggest problem with Damore’s memo however is that he doesn’t understand what makes a company successful. If a significant fraction of employees think that diversity is important, then it is important. No further justification is needed for this.

Yes, you can argue that increasing diversity may not improve productivity. The data situation on this is murky, to say the least. There’s some story about female CEOs in Sweden that supposedly shows something – but I want to see better statistics before I buy that. And in any case, the USA isn’t Sweden. More importantly, productivity hinges on employees’ well-being. If a diverse workplace is something they value, then that’s something to strive for, period.

What Damore seems to have aimed at, however, was merely to discuss the best way to deal with the current lack of diversity. Biases and unequal opportunities are real. (If you doubt that, you are a problem and should do some reading.) This means that the current representation of women, underprivileged and disabled people, and other minorities, is smaller than it would be in that ideal world which we don’t live in. So what to do about it?

One way to deal with the situation is to wait until the world catches up. Educate people about bias, work to remove obstacles to education, change societal gender images. This works – but it works very slowly.

Worse, one of the biggest obstacles that minorities face is a chicken-and-egg problem that time alone doesn’t cure. People avoid professions in which there are few people like them. This is a hurdle which affirmative action can remove, fast and efficiently.

But there’s a price to pay for preferably recruiting the presently underrepresented. Which is that people supported by diversity efforts face a new prejudice: They weren’t hired because they’re skilled. They were hired because of some diversity policy!

I used to think this backlash has to be avoided at all costs, hence was firmly against affirmative action. But during my years in Sweden, I saw that it does work – at least for women – and also why: It makes their presence unremarkable.

In most of the European North, a woman in a leading position in politics or industry is now commonplace. It’s nothing to stare at and nothing to talk about. And once it’s commonplace, people stop paying attention to a candidate’s gender, which in return reduces bias.

I don’t know, though, if this would also work in science which requires an entirely different skill-set. And social science is messy – it’s hard to tell how much of the success in Northern Europe is due to national culture. Hence, my attitude towards affirmative action remains conflicted.

And let us be clear that, yes, such policies mean every once in a while you will not hire the most skilled person for a job. Therefore, a value judgement must be made here, not a logical deduction from data. Is diversity important enough for you to temporarily tolerate an increased risk of not hiring the most qualified person? That’s the trade-off nobody seems willing to spell out.

I also have to spell out that I am writing this as a European who now works in Europe again. For me, the most relevant contribution to equal opportunity is affordable higher education and health insurance, as well as governmentally paid maternity and parental leave. Without that, socially disadvantaged groups remain underrepresented, and companies continue to fear for revenue when hiring women in their fertile age. That, in all fairness, is an American problem not even Google can solve.

But one also doesn’t solve a problem by yelling “harassment” each time someone asks to discuss whether a diversity effort is indeed effective. I know from my own experience, and a poll conducted at Google confirms, that Damore’s skepticism about current practices is widespread.

It’s something we should discuss. It’s something Google should discuss. Because, for better or worse, this case has attracted much attention. Google’s handling of the situation will set an example for others.

Damore was fired, basically, for making a well-meant, if amateurish, attempt at institutional design, based on woefully incomplete information he picked from published research studies. But however imperfect his attempt, he was fired, in short, for thinking on his own. And what example does that set?

Dear Dr B: Is science democratic?

“Hi Bee,

One of the often repeated phrases here in Italy by so called “science enthusiasts” is that “science is not democratic”, which to me sounds like an excuse for someone to justify some authoritarian or semi-fascist fantasy.

We see this on countless “Science pages”, one very popular example being Fare Serata Con Galileo. It's not a bad page per se, quite the contrary, but the level of comments including variations of “Democracy is overrated”, “Darwin works to eliminate weak and stupid people” and the usual “Science is not democratic” is unbearable. It underscores a troubling “sympathy for authoritarian politics” that to me seems to be more and more common among “science enthusiasts". The classic example it’s made is “the speed of light is not voted”, which to me, as true as it may be, has some sinister resonance.

Could you comment on this on your blog?

Luca S.”

Dear Luca,

Wow, I had no idea there’s so much hatred in the backyards of science communication.

Hand count at convention of the German
party CDU. Image Source: AFP

It’s correct that science isn’t democratic, but that doesn’t mean it’s fascistic. Science is a collective enterprise and a type of adaptive system, just like democracy is. But science isn’t democratic any more than sausage is a fruit just because you can eat both.

In an adaptive system, small modifications create a feedback that leads to optimization. The best-known example is probably Darwinian evolution, in which a species’ genetic information receives feedback through natural selection, thereby optimizing the odds of successful reproduction. A market economy is also an adaptive system. Here, the feedback happens through pricing. A free market optimizes “utility” that is, roughly speaking, a measure of the agents’ (customers/producers) satisfaction.

Democracy too is an adaptive system. Its task is to match decisions that affect the whole collective with the electorate’s values. We use democracy to keep our “is” close to the “ought.”

Democracies are more stable than monarchies or autocracies because an independent leader is unlikely to continuously make decisions which the governed people approve of. And the more governed people disapprove, the more likely they are to chop off the king’s head. Democracy, hence, works better than monarchy for the same reason a free market works better than a planned economy: It uses feedback for optimization, and thereby increases the probability for serving peoples’ interests.

The scientific system too uses feedback for optimization – this is the very basis of the scientific method: A hypothesis that does not explain observations has to be discarded or amended. But that’s about where similarities end.

The most important difference between the scientific, democratic, and economic system is the weight of an individual’s influence. In a free market, influence is weighted by wealth: The more money you can invest, the more influence you can have. In a democracy, each voter’s opinion has the same weight. That’s pretty much the definition of democracy – and note that this is a value in itself.

In science, influence is correlated with expertise. While expertise doesn’t guarantee influence, an expert is more likely to hold relevant knowledge, hence expertise is in practice strongly correlated with influence.

There are a lot of things that can go wrong with scientific self-optimization – and a lot of things do go wrong – but that’s a different story and shall be told another time. Still, optimizing hypotheses by evaluating empirical adequacy is how it works in principle. Hence, science clearly isn’t democratic.

Democracy, however, plays an important role for science.

For science to work properly, scientists must be free to communicate and discuss their findings. Non-democratic societies often stifle discussion on certain topics which can create a tension with the scientific system. This doesn’t have to be the case – science can flourish just fine in non-democratic societies – but free speech strongly links the two.

Science also plays an important role for democracy.

Politics isn’t done with polling the electorate on what future they would like to see. Elected representatives then have to find out how to best work towards this future, and scientific knowledge is necessary to get from “is” to “ought.”

But things often go wrong at the step from “is” to “ought.” Trouble is, the scientific system does not export knowledge in a format that can be directly imported by the political system. The information that elected representatives would need to make decisions is a breakdown of predictions with quantified risks and uncertainties. But science doesn’t come with a mechanism to aggregate knowledge. For an outsider, it’s a mess of technical terms and scientific papers and conferences – and every possible opinion seems to be defended by someone!

As a result, public discourse often draws on the “scientific consensus” but this is a bad way to quantify risk and uncertainty.

To begin with, scientists are terribly disagreeable and the only consensuses I know of are those on thousand years-old questions. More important, counting the numbers of people who agree with a statement simply isn’t an accurate quantifier of certainty. The result of such counting inevitably depends on how much expertise the counted people have: Too little expertise, and they’re likely to be ill-informed. Too much expertise, and they’re likely to have personal stakes in the debate. Worse, still, the head-count can easily be skewed by pouring money into some research programs.

Therefore, the best way we presently have make scientific knowledge digestible for politicians is to use independent panels. Such panels – done well – can both circumvent the problem of personal bias and the skewed head count. In the long run, however, I think we need a fourth arm of government to prevent politicians from attempting to interpret scientific debate. It’s not their job and it shouldn’t be.

But those “science enthusiasts” who you complain about are as wrong-headed as the science deniers who selectively disregard facts that are inconvenient for their political agenda. Both of them confuse opinions about what “ought to be” with the question how to get there. The former is a matter of opinion, the latter isn’t.

That vaccine debate that you mentioned, for example. It’s one question what are the benefits of vaccination and who is at risk from side-effects – that’s a scientific debate. It’s another question entirely whether we should allow parents to put their and other peoples’ children at an increased risk of early death or a life of disability. There’s no scientific and no logical argument that tells us where to draw the line.

Personally, I think parents who don’t vaccinate their kids are harming minors and society shouldn’t tolerate such behavior. But this debate has very little to do with scientific authority. Rather, the issue is to what extent parents are allowed to ruin their offspring’s life. Your values may differ from mine.

There is also, I should add, no scientific and no logical argument for counting the vote of everyone (above some quite arbitrary age threshold) with the same weight. Indeed, as Daniel Gilbert argues, we are pretty bad at predicting what will make us happy. If he’s right, then the whole idea of democracy is based on a flawed premise.

So – science isn’t democratic, never has been, never will be. But rather than stating the obvious, we should find ways to better integrate this non-democratically obtained knowledge into our democracies. Claiming that science settles political debate is as stupid as ignoring knowledge that is relevant to make informed decisions.

Science can only help us to understand the risks and opportunities that our actions bring. It can’t tell us what to do.

Thanks for an interesting question.

May-day Pope-hope

Pope Francis meets Stephen Hawking.
[Photo: Piximus.]

My husband is a Roman Catholic, so is his whole family. I’m a heathen. We’re both atheists, but dear husband has steadfastly refused to leave the church. That he throws out money with the annual “church tax” (imo a great failure of secularization) has been a recurring point of friction between us. But as of recently I’ve stopped bitching about it – because the current Pope is just so damn awesome.

Pope Francis, born in Argentina, is the 266th leader of the Catholic Church. The man’s 80 years old, but within only two years he has overhauled his religion. He accepts Darwinian evolution as well as the Big Bang theory. He addresses ecological problems – loss of biodiversity, climate change, pollution – and calls for action, while worrying that “international politics has [disregarded] well-founded scientific opinion about the state of our planet.” He also likes exoplanets:

“How wonderful would it be if the growth of scientific and technological innovation would come along with more equality and social inclusion. How wonderful would it be, while we discover faraway planets, to rediscover the needs of the brothers and sisters orbiting around us.”

I find this remarkable, not only because his attitude flies in the face of those who claim religion is incompatible with science. More important, Pope Francis succeeds where the vast majority of politicians fail. He listens to scientists, accepts the facts, and bases calls for actions on evidence. Meanwhile, politicians left and right bend facts to mislead people about what’s in whose interest.

And Pope Francis is a man whose word matters big time. About 1.3 billion people in the world are presently members of his Church. For the Catholics, the Pope is the next best thing to God. The Pope is infallible, and he can keep going until he quite literally drops dead. Compared to Francis, Tweety-Trump is a fly circling a horse’s ass.

Global distribution of Catholics.
[Source: Wikipedia. By Starfunker226, CC BY-SA 3.0, Link.]

This current Pope is demonstrably not afraid of science, and this gives me hope for the future. Most of the tension between science and religion that we witness today is caused by certain aspects of monotheistic religions that are obviously in conflict with science – if taken literally. But it’s an unnecessary tension. It would be easy enough to throw out what are basically thousand years old stories. But this will only happen once the religious understand it will not endanger the core of their beliefs.

Science advocates like to argue that religion is incompatible with science for religion is based on belief, not reason. But this neglects that science, too, is ultimately based on beliefs.

Most scientists, for example, believe in an external reality. They believe, for the biggest part, that knowledge is good. They believe that the world can be understood, and that this is something humans should strive for.

In the foundations of physics I have seen more specific beliefs. Many of my colleagues, for example, believe that the fundamental laws of nature are simple, elegant, even beautiful. They believe that logical deduction can predict observations. They believe in continuous functions and that infinities aren’t real.

None of this has a rational basis, but physicists rarely acknowledge these beliefs as what they are. Often, I have found myself more comfortable with openly religious people, for at least they are consciously aware of their beliefs and make an effort to prevent it from interfering with research. Even my own discipline, I think, would benefit from a better awareness of the bounds of human rationality. Even my own discipline, I think, could learn from the Pope to tell Is from Ought.

You might not subscribe to the Pope’s idea that “tenderness is the path of choice for the strongest, most courageous men and women.” Honestly, to me doesn’t sound so different from believing that love will quantize gravity. But you don’t have to share the values of the Catholic Church to appreciate here is a world leader who doesn’t confuse facts with values.

Not all publicity is good publicity, not even in science.

“Any publicity is good publicity” is a reaction I frequently get to my complaints about flaky science coverage. I find this attitude disturbing, especially when it comes from scientists.

[img src: gamedesigndojo.com]

To begin with, it’s an idiotic stance towards journalism in general – basically a permission for journalists to write nonsense. Just imagine having the same attitude towards articles on any other topic, say, immigration: Simply shrug off whether the news accurately reports survey results or even correctly uses the word “immigrant.” In that case I hope we agree that not all publicity is good publicity, neither in terms of information transfer nor in terms of public engagement.

Besides, as United Airlines and Pepsi recently served to illustrate, sometimes all you want is that they stop talking about you.

But, you may say, science is different. Scientists have little to lose and much to win from an increased interest in their research.

Well, if you think so, you either haven’t had much experience with science communication or you haven’t paid attention. Thanks to this blog, I have a lot first-hand experience with public engagement due to science writers’ diarrhea. And most of what I witness isn’t beneficial for science at all.

The most serious problem is the awakening after overhype. It’s when people start asking “Whatever happened to this?” Why are we still paying string theorists? Weren’t we supposed to have a theory of quantum gravity by 2015? Why do physicists still don’t know what dark matter is made of? Why can I still not have a meaningful conversation with my phone, where is my quantum computer, and whatever happened to negative mass particles?

That’s a predictable and wide-spread backlash from disappointed hope. Once excitement fades, the consequence is a strong headwind of public ridicule and reduced trust. And that’s for good reasons, because people were, in fact, fooled. In IT development, it goes under the (branded but catchy) name Hype Cycle

[Hype Cycle. Image: Wikipedia]

There isn’t much data on it, but academic research plausibly goes through the same “through of disillusionment” when it falls short of expectations. The more hype, the more hangover when promises don’t pan out, which is why, eg, string theory today takes most of the fire while loop quantum gravity – though in many regards even more of a disappointment – flies mostly under the radar. In the valley of disappointment, then, researchers are haunted both by dwindling financial support as well as by their colleagues’ snark. (If you think that’s not happening, wait for it.)

This overhype backlash, it’s important to emphasize, isn’t a problem journalists worry about. They’ll just drop the topic and move on to the next. We, in science, are the ones who pay for the myth that any publicity is good publicity.

In the long run the consequences are even worse. Too many never-heard-of-again breakthroughs leave even the interested layman with the impression that scientists can no longer be taken seriously. Add to this a lack of knowledge about where to find quality information, and inevitable some fraction of the public will conclude scientific results can’t be trusted, period.

If you have a hard time believing what I say, all you have to do is read comments people leave on such misleading science articles. They almost all fall into two categories. It’s either “this is a crappy piece of science writing” or “mainstream scientists are incompetent impostors.” In both cases the commenters doubt the research in question is as valuable as it was presented.

If you can stomach it, check the I-Fucking-Love-Science facebook comment section every once in a while. It's eye-opening. On recent reports from the latest LHC anomaly, for example, you find gems like “I wish I had a job that dealt with invisible particles, and then make up funny names for them! And then actually get a paycheck for something no one can see! Wow!” and “But have we created a Black Hole yet? That's what I want to know.” Black Holes at the LHC were the worst hype I can recall in my field, and it still haunts us.

Another big concern with science coverage is its impact on the scientific community. I have spoken about this many times with my colleagues, but nobody listens even though it’s not all that complicated: Our attention is influenced by what ideas we are repeatedly exposed to, and all-over-the-news topics therefore bring a high risk of streamlining our interests.

Almost everyone I ever talked to about this simply denied such influence exists because they are experts and know better and they aren’t affected by what they read. Unfortunately, many scientific studies have demonstrated that humans pay more attention to what they hear about repeatedly, and we perceive something as more important the more other people talk about it. That’s human nature.

Other studies that have shown such cognitive biases are neither correlated nor anti-correlated with intelligence. In other words, just because you’re smart doesn’t mean you’re not biased. Some techniques are known to alleviate cognitive biases but the scientific community does not presently used these techniques. (Ample references eg in “Blind Spot,” by Banaji, Greenwald, and Martin.)

I have seen this happening over and over again. My favorite example is the “OPERA anomaly” that seemed to show neutrinos could travel faster than the speed of light. The data had a high statistical significance, and yet it was pretty clear from the start that the result had to be wrong – it was in conflict with other measurements.

But the OPERA anomaly was all over the news. And of course physicists talked about it. They talked about it on the corridor, and at lunch, and in the coffee break. And they did what scientists do: They thought about it.

The more they talked about it, the more interesting it became. And they began to wonder whether not there might be something to it after all. And if maybe one could write a paper about it because, well, we’ve been thinking about it.

Everybody who I spoke to about the OPERA anomaly began their elaboration with a variant of “It’s almost certainly wrong, but...” In the end, it didn’t matter they thought it was wrong – what mattered was merely that it had become socially acceptable to work on it. And every time the media picked it up again, fuel was added to the fire. What was the result? A lot of wasted time.

For physicists, however, sociology isn’t science, and so they don’t want to believe social dynamics is something they should pay attention to. And as long as they don’t pay attention to how media coverage affects their objectivity, publicity skews judgement and promotes a rich-get-richer trend.

Ah, then, you might argue, at least exposure will help you get tenure because your university likes it if their employees make it into the news. Indeed, the “any publicity is good” line I get to hear mainly as justification from people whose research just got hyped.

But if your university measures academic success by popularity, you should be very worried about what this does to your and your colleagues’ scientific integrity. It’s a strong incentive for sexy-yet-shallow, headline-worthy research that won’t lead anywhere in the long run. If you hunt after that incentive, you’re putting your own benefit over the collective benefit society would get from a well-working academic system. In my view, that makes you a hurdle to progress.

What, then, is the result of hype? The public loses: Trust in research. Scientists lose: Objectivity. Who wins? The news sites that place an ad next to their big headlines.

But hey, you might finally admit, it’s just so awesome to see my name printed in the news. Fine by me, if that's your reasoning. Because the more bullshit appears in the press, the more traffic my cleaning service gets. Just don’t say I didn’t warn you.

No, physicists have not created “negative mass”

Thanks to BBC, I will now for several years get emails from know-it-alls who think physicists are idiots not to realize the expansion of the universe is caused by negative mass. Because that negative mass, you must know, has actually been created in the lab:

The Independent declares this turns physics “completely upside down”

And if you think that was crappy science journalism, The Telegraph goes so far to insists it’s got something to do with black holes

Not that they offer so much as a hint of an explanation what black holes have to do with anything.

These disastrous news items purport to summarize a paper that recently got published in Physics Review Letters, one of the top journals in the field:

Negative mass hydrodynamics in a Spin-Orbit--Coupled Bose-Einstein Condensate
M. A. Khamehchi, Khalid Hossain, M. E. Mossman, Yongping Zhang, Th. Busch, Michael McNeil Forbes, P. Engels
Phys. Rev. Lett. 118, 155301 (2017)
arXiv:1612.04055 [cond-mat.quant-gas]

This paper reports the results of an experiment in which the physicists created a condensate that behaves as if it has a negative effective mass.

The little word “effective” does not appear in the paper’s title – and not in the screaming headlines – but it is important. Physicists use the preamble “effective” to indicate something that is not fundamental but emergent, and the exact definition of such a term is often a matter of convention.

The “effective radius” of a galaxy, for example, is not its radius. The “effective nuclear charge” is not the charge of the nucleus. And the “effective negative mass” – you guessed it – is not a negative mass.

The effective mass is merely a handy mathematical quantity to describe the condensate’s behavior.

The condensate in question here is a supercooled cloud of about ten thousand Rubidium atoms. To derive its effective mass, you look at the dispersion relation – ie the relation between energy and momentum – of the condensate’s constituents, and take the second derivative of the energy with respect to the momentum. That thing you call the inverse effective mass. And yes, it can take on negative values.
 
If you plot the energy against the momentum, you can read off the regions of negative mass from the curvature of the resulting curve. It’s clear to see in Fig 1 of the paper, see below. I added the red arrow to point to the region where the effective mass is negative.

Fig 1 from arXiv:1612.04055 [cond-mat.quant-gas]

As to why that thing is called effective mass, I had to consult a friend, David Abergel, who works with cold atom gases. His best explanation is that it’s a “historical artefact.” And it’s not deep: It’s called an effective mass because in the usual non-relativistic limit E=p²/m, so if you take two derivatives of E with respect to p, you get the inverse mass. Then, if you do the same for any other relation between E and p you call the result an inverse effective mass.

It's a nomenclature that makes sense in context, but it probably doesn’t sound very headline-worthy:

“Physicists created what’s by historical accident still called an effective negative mass.”

In any case, if you use this definition, you can rewrite the equations of motion of the fluid. They then resemble the usual hydrodynamic equations with a term that contains the inverse effective mass multiplied by a force.

What this “negative mass” hence means is that if you release the condensate from a trapping potential that holds it in place, it will first start to run apart. And then no longer run apart. That pretty much sums up the paper.

The remaining force which the fluid acts against, it must be emphasized, is then not even an external force. It’s a force that comes from the quantum pressure of the fluid itself.

So here’s another accurate headline:

“Physicists observe fluid not running apart.”

This is by no means to say that the result is uninteresting! Indeed, it’s pretty cool that this fluid self-limits its expansion thanks to long-range correlations which come from quantum effects. I’ll even admit that thinking of the behavior as if the fluid had a negative effective mass may be a useful interpretation. But that still doesn’t mean physicists have actually created negative mass.

And it has nothing to do with black holes, dark energy, wormholes, and the like. Trust me, physics is still upside up.

Catching Light – New Video!

I have many shortcomings, like leaving people uncertain whether they’re supposed to laugh or not. But you can’t blame me for lack of vision. I see a future in which science has become a cultural good, like sports, music, and movies. We’re not quite there yet, but thanks to the Foundational Questions Institute (FQXi) we’re a step closer today.



This is the first music video in a series of three, sponsored by FQXi, for which I’ve teamed up with Timo Alho and Apostolos Vasileiadis. And, believe it or not, all three music videos are about physics!

You’ve met Apostolos before on this blog. He’s the one who, incredibly enough, used his spare time as an undergraduate to make a short film about gauge symmetry. I know him from my stay in Stockholm, where he completed a masters degree in physics. Apostolos then, however, decided that research wasn’t for him. He has since founded a company – Third Panda  – and works as freelance videographer.

Timo Alho is one of the serendipitous encounters I’ve made on this blog. After he left some comments on my songs (mostly to point out they’re crappy) it turned out not only is he a theoretical physicist too, but we were both attending the same conference a few weeks later. Besides working on what passes as string theory these days, Timo also plays the keyboard in two bands and knows more than I about literally everything to do with songwriting and audio processing and, yes, about string theory too.

Then I got a mini-grant from FQXi that allowed me to coax the two young men into putting up with me, and five months later I stood in the hail, in a sleeveless white dress, on a beach in Crete, trying to impersonate electromagnetic radiation.

This first music video is about Einstein’s famous thought experiment in which he imagined trying to catch light. It takes on the question how much can be learned by introspection. You see me in the role of light (I am part of the master plan), standing in for nature more generally, and Timo as the theorist trying to understand nature’s working while barely taking notice of it (I can hear her talk to me at night).

The two other videos will follow early May and mid of May, so stay tuned for more!

Update April 21: 

Since several people asked, here are the lyrics. The YouTube video has captions - to see them, click on the CC icon in the bottom bar.

[Chorus]
I am part of the master plan
Every woman, every man
I have seen them come and go
Go with the flow

I have seen that we all are one
I know all and every one
I was here when the sun was born
Ages ago

[Verse]
In my mind
I have tried
Catching light
Catching light

In my mind
I have left the world behind

Every time I close my eyes
All of nature's open wide
I can hear her
Talk to me at night

In my mind I have been trying
Catching light outside of time
I collect it in a box
Collect it in a box

Every time I close my eyes
All of nature's open wide
I can hear her
Talk to me at night

[Repeat Chorus]

[Interlude, Einstein recording]
The scientific method itself
would not have led anywhere,
it would not even have been formed
Without a passionate striving for a clear understanding.
Perfection of means
and confusion of goals
seem in my opinion
to characterize our age.

[Repeat Chorus]

Book rant: “Universal” by Brian Cox and Jeff Forshaw

Universal: A Guide to the Cosmos
Brian Cox and Jeff Forshaw
Da Capo Press (March 28, 2017)
(UK Edition, Allen Lane (22 Sept. 2016))

I was meant to love this book.

In “Universal” Cox and Forshaw take on astrophysics and cosmology, but rather than using the well-trodden historic path, they offer do-it-yourself instructions.

The first chapters of the book start with every-day observations and simple calculations, by help of which the reader can estimate eg the radius of Earth and its mass, or – if you let a backyard telescope with a 300mm lens and equatorial mount count as every-day items – the distance to other planets in the solar system.

Then, the authors move on to distances beyond the solar system. With that, self-made observations understandably fade out, but are replaced with publicly available data. Cox and Forshaw continue to explain the “cosmic distance ladder,” variable stars, supernovae, redshift, solar emission spectra, Hubble’s law, the Herzsprung-Russell diagram.

Set apart from the main text, the book has “boxes” (actually pages printed white on black) with details of the example calculations and the science behind them. The first half of the book reads quickly and fluidly and reminds me in style of school textbooks: They make an effort to illuminate the logic of scientific reasoning, with some historical asides, and concrete numbers. Along the way, Cox and Forshaw emphasize that the great power of science lies in the consistency of its explanations, and they highlight the necessity of taking into account uncertainty both in the data and in the theories.

The only thing I found wanting in the first half of the book is that they use the speed of light without explaining why it’s constant or where to get it from, even though that too could have been done with every-day items. But then maybe that’s explained in their first book (which I haven’t read).

For me, the fascinating aspect of astrophysics and cosmology is that it connects the physics of the very small scales with that of the very large scales, and allows us to extrapolate both into the distant past and future of our universe. Even though I’m familiar with the research, it still amazes me just how much information about the universe we have been able to extract from the data in the last two decades.

So, yes, I was meant to love this book. I would have been an easy catch.

Then the book continues to explain the dark matter hypothesis as a settled fact, without so much as mentioning any shortcomings of LambdaCDM, and not a single word on modified gravity. The Bullet Cluster is, once again, used as a shut-up argument – a gross misrepresentation of the actual situation, which I previously complained about here.

Inflation gets the same treatment: It’s presented as if it’s a generally accepted model, with no discussion given to the problem of under-determination, or whether inflation actually solves problems that need a solution (or solves the problems period).

To round things off, the authors close the final chapter with some words on eternal inflation and bubble universes, making a vague reference to string theory (because that’s also got something to do with multiverses you see), and then they suggest this might mean we live in a computer simulation:

“Today, the cosmologists responsible for those simulations are hampered by insufficient computing power, which means that they can only produce a small number of simulations, each with different values for a few key parameters, like the amount of dark matter and the nature of the primordial perturbations delivered at the end of inflation. But imagine that there are super-cosmologists who know the String Theory that describes the inflationary Multiverse. Imagine that they run a simulation in their mighty computers – would the simulated creatures living within one of the simulated bubble universes be able to tell that they were in a simulation of cosmic proportions?”

Wow. After all the talk about how important it is to keep track of uncertainty in scientific reasoning, this idea is thrown at the reader with little more than a sentence which mentions that, btw, “evidence for inflation” is “not yet absolutely compelling” and there is “no firm evidence for the validity of String Theory or the Multiverse.” But, hey, maybe we live in a computer simulation, how cool is that?

Worse than demonstrating slippery logic, their careless portrayal of speculative hypotheses as almost settled is dumb. Most of the readers who buy the book will have heard of modified gravity as dark matter’s competitor, and will know the controversies around inflation, string theory, and the multiverse: It’s been all over the popular science news for several years. That Cox and Forshaw don’t give space to discussing the pros and cons in a manner that at least pretends to be objective will merely convince the scientifically-minded reader that the authors can’t be trusted.

The last time I thought of Brian Cox – before receiving the review copy of this book – it was because a colleague confided to me that his wife thinks Brian is sexy. I managed to maneuver around the obviously implied question, but I’ll answer this one straight: The book is distinctly unsexy. It’s not worthy of a scientist.

I might have been meant to love the book, but I ended up disappointed about what science communication has become.

[Disclaimer: Free review copy.]

No, we probably don’t live in a computer simulation

According to Nick Bostrom of the Future of Humanity Institute, it is likely that we live in a computer simulation. And one of our biggest existential risks is that the superintelligence running our simulation shuts it down.

The simulation hypothesis, as it’s called, enjoys a certain popularity among people who like to think of themselves as intellectual, believing it speaks for their mental flexibility. Unfortunately it primarily speaks for their lacking knowledge of physics.

Among physicists, the simulation hypothesis is not popular and that’s for a good reason – we know that it is difficult to find consistent explanations for our observations. After all, finding consistent explanations is what we get paid to do.

Proclaiming that “the programmer did it” doesn’t only not explain anything - it teleports us back to the age of mythology. The simulation hypothesis annoys me because it intrudes on the terrain of physicists. It’s a bold claim about the laws of nature that however doesn’t pay any attention to what we know about the laws of nature.

First, to get it out of the way, there’s a trivial way in which the simulation hypothesis is correct: You could just interpret the presently accepted theories to mean that our universe computes the laws of nature. Then it’s tautologically true that we live in a computer simulation. It’s also a meaningless statement.

A stricter way to speak of the computational universe is to make more precise what is meant by ‘computing.’ You could say, for example, that the universe is made of bits and an algorithm encodes an ordered time-series which is executed on these bits. Good - but already we’re deep in the realm of physics.

If you try to build the universe from classical bits, you won’t get quantum effects, so forget about this – it doesn’t work. This might be somebody’s universe, maybe, but not ours. You either have to overthrow quantum mechanics (good luck), or you have to use qubits. [Note added for clarity: You might be able to get quantum mechanics from a classical, nonlocal approach, but nobody knows how to get quantum field theory from that.]

Even from qubits, however, nobody’s been able to recover the presently accepted fundamental theories – general relativity and the standard model of particle physics. The best attempt to date is that by Xiao-Gang Wen and collaborators, but they are still far away from getting back general relativity. It’s not easy.

Indeed, there are good reasons to believe it’s not possible. The idea that our universe is discretized clashes with observations because it runs into conflict with special relativity. The effects of violating the symmetries of special relativity aren’t necessarily small and have been looked for – and nothing’s been found.

For the purpose of this present post, the details don’t actually matter all that much. What’s more important is that these difficulties of getting the physics right are rarely even mentioned when it comes to the simulation hypothesis. Instead there’s some fog about how the programmer could prevent simulated brains from ever noticing contradictions, for example contradictions between discretization and special relativity.

But how does the programmer notice a simulated mind is about to notice contradictions and how does he or she manage to quickly fix the problem? If the programmer could predict in advance what the brain will investigate next, it would be pointless to run the simulation to begin with. So how does he or she know what are the consistent data to feed the artificial brain with when it decides to probe a specific hypothesis? Where does the data come from? The programmer could presumably get consistent data from their own environment, but then the brain wouldn’t live in a simulation.

It’s not that I believe it’s impossible to simulate a conscious mind with human-built ‘artificial’ networks – I don’t see why this should not be possible. I think, however, it is much harder than many future-optimists would like us to believe. Whatever the artificial brains will be made of, they won’t be any easier to copy and reproduce than human brains. They’ll be one-of-a-kind. They’ll be individuals.

It therefore seems implausible to me that we will soon be outnumbered by artificial intelligences with cognitive skills exceeding ours. More likely, we will see a future in which rich nations can afford raising one or two artificial consciousnesses and then consult them on questions of importance.

So, yes, I think artificial consciousness is on the horizon. I also think it’s possible to convince a mind with cognitive abilities comparable to that of humans that their environment is not what they believe it is. Easy enough to put the artificial brain in a metaphoric vat: If you don’t give it any input, it would never be any wiser. But that’s not the environment I experience and, if you read this, it’s not the environment you experience either. We have a lot of observations. And it’s not easy to consistently compute all the data we have.

Besides, if the reason you build an artificial intelligences is consultation, making them believe reality is not what it seems is about the last thing you’d want.

Hence, the first major problem with the simulation hypothesis is to consistently create all the data which we observe by any means other than the standard model and general relativity – because these are, for all we know, not compatible with the universe-as-a-computer.

Maybe you want to argue it is only you alone who is being simulated, and I am merely another part of the simulation. I’m quite sympathetic to this reincarnation of solipsism, for sometimes my best attempt of explaining the world is that it’s all an artifact of my subconscious nightmares. But the one-brain-only idea doesn’t work if you want to claim that it is likely we live in a computer simulation.

To claim it is likely we are simulated, the number of simulated conscious minds must vastly outnumber those of non-simulated minds. This means the programmer will have to create a lot of brains. Now, they could separately simulate all these brains and try to fake an environment with other brains for each, but that would be nonsensical. The computationally more efficient way to convince one brain that the other brains are “real” is to combine them in one simulation.

Then, however, you get simulated societies that, like ours, will set out to understand the laws that govern their environment to better use it. They will, in other words, do science. And now the programmer has a problem, because it must keep close track of exactly what all these artificial brains are trying to probe.

The programmer could of course just simulate the whole universe (or multiverse?) but that again doesn’t work for the simulation argument. Problem is, in this case it would have to be possible to encode a whole universe in part of another universe, and parts of the simulation would attempt to run their own simulation, and so on. This has the effect of attempting to reproduce the laws on shorter and shorter distance scales. That, too, isn’t compatible with what we know about the laws of nature. Sorry.

Stephen Wolfram (from Wolfram research) recently told John Horgan that:

“[Maybe] down at the Planck scale we’d find a whole civilization that’s setting things up so our universe works the way it does.”

I cried a few tears over this.

The idea that the universe is self-similar and repeats on small scales – so that elementary particles are built of universes which again contain atoms and so on – seems to hold a great appeal for many. It’s another one of these nice ideas that work badly. Nobody’s ever been able to write down a consistent theory that achieves this – consistent both internally and with our observations. The best attempt I know of are limit cycles in theory space but to my knowledge that too doesn’t really work.

Again, however, the details don’t matter all that much – just take my word for it: It’s not easy to find a consistent theory for universes within atoms. What matters is the stunning display of ignorance – for not to mention arrogance –, demonstrated by the belief that for physics at the Planck scale anything goes. Hey, maybe there’s civilizations down there. Let’s make a TED talk about it next. For someone who, like me, actually works on Planck scale physics, this is pretty painful.

To be fair, in the interview, Wolfram also explains that he doesn’t believe in the simulation hypothesis, in the sense that there’s no programmer and no superior intelligence laughing at our attempts to pin down evidence for their existence. I get the impression he just likes the idea that the universe is a computer. (Note added: As a commenter points out, he likes the idea that the universe can be described as a computer.)

In summary, it isn’t easy to develop theories that explain the universe as we see it. Our presently best theories are the standard model and general relativity, and whatever other explanation you have for our observations must first be able to reproduce these theories’ achievements. “The programmer did it” isn’t science. It’s not even pseudoscience. It’s just words.

All this talk about how we might be living in a computer simulation pisses me off not because I’m afraid people will actually believe it. No, I think most people are much smarter than many self-declared intellectuals like to admit. Most readers will instead correctly conclude that today’s intelligencia is full of shit. And I can’t even blame them for it.

Fake news wasn’t hard to predict – But what’s next?

In 2008, I wrote a blogpost which began with a dark vision – a presidential election led astray by fake news.

I’m not much of a prophet, but it wasn’t hard to predict. Journalism, for too long, attempted the impossible: Make people pay for news they don’t want to hear.

It worked, because news providers, by and large, shared an ethical code. Journalists aspired to tell the truth; their passion was unearthing and publicizing facts – especially those that nobody wanted to hear. And as long as the professional community held the power, they controlled access to the press – the device – and kept up the quality.

But the internet made it infinitely easy to produce and distribute news, both correct and incorrect. Fat headlines suddenly became what economists call an “intangible good.” No longer does it rely on a physical resource or a process of manufacture. News now can be created, copied, and shared by anyone, anywhere, with almost zero investment.

By the early 00s, anybody could set up a webpage and produce headlines. From thereon, quality went down. News makes the most profit if it’s cheap and widely shared. Consequently, more and more outlets offer the news people want to read –that’s how the law of supply and demand is supposed to work after all.

What we have seen so far, however, is only the beginning. Here’s what’s up next:

• 1. Fake News Get Organized
  
  An army of shadow journalists specializes in fake news, pitching it to alternative news outlets. These outlets will mix real and fake news. It becomes increasingly hard to tell one from the other.
  
  
• 2. Fake News Becomes Visual
  
  “Picture or it didn’t happen,” will soon be a thing of the past. Today, it’s still difficult to forge photos and videos. But software becomes better, and cheaper, and easier to obtain, and soon it will take experts to tell real from fake.
  
  
• 3. Fake News Get Cozy
  
  Anger isn’t sustainable. In the long run, most people want good news – they want to be reassured everything’s fine. The war in Syria is over. The earthquake risk in California is low. The economy is up. The chocolate ratio has been raised again.
  
  
• 4. Cooperations Throw the Towel
  
  Facebook and Google and Yahoo conclude out it’s too costly to assess the truth value of information passed on by their platforms, and decide it’s not their task. They’re right.
• 5. Fake News Has Real-World Consequences
  
  We’ll see denial of facts leading to deaths of thousands of people. I mean lack of earthquake warning systems because the risk was believed fear-mongering. I mean riots over terrorist attacks that never happened. I mean collapsed buildings and toxic infant formula because who cares about science. We’ll get there.
  
  

The problem that fake news poses for democratic societies attracted academic interest already a decade ago. Triggered by the sudden dominance of Google as search engine, it entered the literature under the name “Googlearchy.”

Democracy relies on informed decision making. If the electorate doesn’t know what’s real, democratic societies can’t identify good ways to carry out the people’s will. You’d think that couldn’t be in anybody’s interest, but it is – if you can make money from misinformation.

Back then, the main worry focused on search engines as primary information providers. Someone with more prophetic skills might have predicted that social networks would come to play the central role for news distribution, but the root of the problem is the same: Algorithms are designed to deliver news which users like. That optimizes profit, but degrades the quality of news.

Economists of the Chicago School would tell you that this can’t be. People’s behavior reveals what they really want, and any regulation of the free market merely makes the fulfillment of their wants less efficient. If people read fake news, that’s what they want – the math proves it!

But no proof is better than its assumptions, and one central assumption for this conclusion is that people can’t have mutually inconsistent desires. We’re supposed to have factored in long-term consequences of today’s actions, properly future-discounted and risk-assessed. In other words, we’re supposed to know what’s good for us and our children and grand-grand-children and make rational decisions to work towards that goal.

In reality, however, we often want what’s logically impossible. Problem is, a free market, left unattended, caters predominantly to our short-term wants.

On the risk of appearing to be inconsistent, economists are right when they speak of revealed preferences as the tangible conclusion of our internal dialogues. It’s just that economists, being economists, like to forget that people have a second way of revealing preferences – they vote.

We use democratic decision making to ensure the long-term consequences of our actions are consistent with the short-term ones, like putting a price on carbon. One of the major flaws of current economic theory is that it treats the two systems, economic and political, as separate, when really they’re two sides of the same coin. But free markets don’t work without a way to punish forgery, lies, and empty promises.

This is especially important for intangible goods – those which can be reproduced with near-zero effort. Intangible goods, like information, need enforced copyright, or else quality becomes economically unsustainable. Hence, it will take regulation, subsidies, or both to prevent us from tumbling down into the valley of alternative facts.

In the last months I’ve seen a lot of finger-pointing at scientists for not communicating enough or not communicating correctly, as if we were the ones to blame for fake news. But this isn’t our fault. It’s the media which has a problem – and it’s a problem scientists solved long ago.

The main reason why fake news is hard to identify, and why it remains profitable to reproduce what other outlets have already covered, is that journalists – in contrast to scientists – are utterly intransparent about their doings.

As a blogger, I see this happening constantly. I know that many, if not most, science writers closely follow science blogs. And the professional writers frequently report on topics previously covered by bloggers – without doing as much as naming their sources, not to mention referencing them.

This isn’t merely a personal paranoia. I know this because in several instances science writers actually told me that my blogpost about this-or-that has been so very useful. Some even asked me to share links to their articles they wrote based on it. Let that sink in for a moment – they make money from my expertise, don’t give me credits, and think that this is entirely appropriate behavior. And you wonder why fake news is economically profitable?

For a scientist, that’s mindboggling. Our currency is citations. Proper credits is pretty much all we want. Keep the money, but say my name.

I understand that journalists have to protect some sources, so don’t misunderstand me. I don’t mean they have to spill beans about their exclusive secrets. What I mean is simply that a supposed news outlet that merely echoes what’s been reported elsewhere should be required to refer to the earlier article.

Of course this would imply that the vast majority of existing news sites were revealed as copy-cats and lose readers. And of course it isn’t going to happen because nobody’s going to enforce it. If I saw even a remote chance of this happening, I wouldn’t have made the above predictions, would I?

What’s even more perplexing for a scientist, however, is that news outlets, to the extent that they do fact-checks, don’t tell customers that they fact-check, or what they fact-check, or how they fact-check.

Do you know, for example, which science magazines fact-check their articles? Some do, some don’t. I know for a few because I’ve been border-crossing between scientists and writers for a while. But largely it’s insider knowledge – I think it should be front-page information. Listen, Editor-in-Chief: If you fact-check, tell us.

It isn’t going to stop fake news, but I think a more open journalistic practice and publicly stated adherence to voluntary guidelines could greatly alleviate it. It probably makes you want to puke, but academics are good at a few things and high community standards are one of them. And that is what journalisms need right now.

I know, this isn’t exactly the cozy, shallow, good news that shares well. But it will be a great pleasure when, in ten years, I can say: I told you so.

Stephen Hawking turns 75. Congratulations! Here’s what to celebrate.

If people know anything about physics, it’s the guy in a wheelchair who speaks with a computer. Google “most famous scientist alive” and the answer is “Stephen Hawking.” But if you ask a physicist, what exactly is he famous for?

Hawking became “officially famous” with his 1988 book “A Brief History of Time.” Among physicists, however, he’s more renowned for the singularity theorems. In his 1960s work together with Roger Penrose, Hawking proved that singularities form under quite general conditions in General Relativity, and they developed a mathematical framework to determine when these conditions are met.

Before Hawking and Penrose’s work, physicists had hoped that the singularities which appeared in certain solutions to General Relativity were mathematical curiosities of little relevance for physical reality. But the two showed that this was not so, that, to the very contrary, it’s hard to avoid singularities in General Relativity.

Since this work, the singularities in General Relativity are understood to signal the breakdown of the theory in regions of high energy-densities. In 1973, together with George Ellis, Hawking published the book “The Large Scale Structure of Space-Time” in which this mathematical treatment is laid out in detail. Still today it’s one of the most relevant references in the field.

Only a year later, in 1974, Hawking published a seminal paper in which he demonstrates that black holes give off thermal radiation, now referred to as “Hawking radiation.” This evaporation of black holes results in the black hole information loss paradox which is still unsolved today. Hawking’s work demonstrated clearly that the combination of General Relativity with the quantum field theories of the standard model spells trouble. Like the singularity theorems, it’s a result that doesn’t merely indicate, but prove that we need a theory of quantum gravity in order to consistently describe nature.

While the 1974 paper was predated by Bekenstein’s finding that black holes resemble thermodynamical systems, Hawking’s derivation was the starting point for countless later revelations. Thanks to it, physicists understand today that black holes are a melting pot for many different fields of physics – besides general relativity and quantum field theory, there is thermodynamics and statistical mechanics, and quantum information and quantum gravity. Let’s not forget astrophysics, and also mix in a good dose of philosophy. In 2017, “black hole physics” could be a subdiscipline in its own right – and maybe it should be. We owe much of this to Stephen Hawking.

In the 1980s, Hawking worked with Jim Hartle on the no-boundary proposal according to which our universe started in a time-less state. It’s an appealing idea whose time hasn’t yet come, but I believe this might change within the next decade or so.

After this, Hawking tries several times to solve the riddle of black hole information loss that he posed himself, most recently in early 2016. While his more recent work has been met with interest in the community, it hasn’t been hugely impactful – it attracts significantly more attention by journalists than by physicists.

As a physicist myself, I frequently get questions about Stephen Hawking: “What’s he doing these days?” – I don’t know. “Have you ever met him?” – He slept right through it. “Do you also work on the stuff that he works on?” – I try to avoid it. “Will he win a Nobel Prize?” – Ah. Good question.

Hawking’s shot at the Nobel Prize is the Hawking radiation. The astrophysical black holes which we can presently observe have a temperature way too small to be measured in the foreseeable future. But since the temperature increases for smaller mass, lighter black holes are hotter, and could allow us to measure Hawking radiation.

Black holes of sufficiently small masses could have formed from density fluctuations in the early universe and are therefore referred to as “primordial black holes.” However, none of them have been seen, and we have tight observational constraints on their existence from a variety of data. It isn’t yet entirely excluded that they are around, but I consider it extremely unlikely that we’ll observe one of these within my lifetime.

For what the Nobel is concerned, this leaves the Hawking radiation in gravitational analogues. In this case, one uses a fluid to mimic a curved space-time background. The mathematical formulation of this system is (in certain approximations) identical to that of an actual black hole, and consequently the gravitational analogues should also emit Hawking radiation. Indeed, Jeff Steinhauer claims that he has measured this radiation.

At the time of writing, it’s still somewhat controversial whether Steinhauer has measured what he thinks he has. But I have little doubt that sooner or later this will be settled – the math is clear: The radiation should be there. It might take some more experimental tinkering, but I’m confident sooner or later it’ll be measured.

Sometimes I hear people complain: “But it’s only an analogy.” I don’t understand this objection. Mathematically it’s the same. That in the one case the background is an actually curved space-time and in the other case it’s an effectively curved space-time created by a flowing fluid doesn’t matter for the calculation. In either situation, measuring the radiation would demonstrate the effect is real.

However, I don’t think that measuring Hawking radiation in an analogue gravity system would be sufficient to convince the Nobel committee Hawking deserves the prize. For that, the finding would have to have important implications beyond confirming a 40-years-old computation.

One way this could happen, for example, would be if the properties of such condensed matter systems could be exploited as quantum computers. This isn’t as crazy as it sounds. Thanks to work built on Hawking’s 1974 paper we know that black holes are both extremely good at storing information and extremely efficient at distributing it. If that could be exploited in quantum computing based on gravitational analogues, then I think Hawking would be in line for a Nobel. But that’s a big “if.” So don’t bet on it.

Besides his scientific work, Hawking has been and still is a master of science communication. In 1988, “A Brief History of Time” was a daring book about abstract ideas in a fringe area of theoretical physics. Hawking, to everybody’s surprise, proved that the public has an interest in esoteric problems like what happens if you fall into a black hole, what happed at the Big Bang, or whether god had any choice when he created the laws of nature.

Since 1988, the popular science landscape has changed dramatically. There are more books about theoretical physics than ever before and they are more widely read than ever before. I believe that Stephen Hawking played a big role in encouraging other scientists to write about their own research for the public. It certainly was an inspiration for me.

So, Happy Birthday, Stephen, and thank you.

How to use an "argument from authority"

I spent the holidays playing with the video animation software. As a side-effect, I produced this little video.



If you'd rather read than listen, here's the complete voiceover:

It has become a popular defense of science deniers to yell “argument from authority” when someone quotes an experts’ opinion. Unfortunately, the argument from authority is often used incorrectly.

What is an “argument from authority”?

An “argument from authority” is a conclusion drawn not by evaluating the evidence itself, but by evaluating an opinion about that evidence. It is also sometimes called an “appeal to authority”.

Consider Bob. Bob wants to know what follows from A. To find out, he has a bag full of knowledge. The perfect argument would be if Bob starts with A and then uses his knowledge to get to B to C to D and so on until he arrives at Z. But reality is never perfect.

Let’s say Bob wants to know what’s the logarithm of 350,000. In reality he can’t find anything useful in his bag of knowledge to answer that question. So instead he calls his friend, the Pope. The Pope says “The log is 4.8.” So, Bob concludes, the log of 350,000 is 4.8 because the Pope said so.

That’s an argument from authority – and you have good reasons to question its validity.

But unlike other logical fallacies, an argument from authority isn’t necessarily wrong. It’s just that, without further information about the authority that has been consulted, you don’t know how good the argument it is.

Suppose Bob hadn’t asked the Pope what’s the log of 350,000 but instead he’d have asked his calculator. The calculator says it’s approximately 5.544.

We don’t usually call this an argument from authority. But in terms of knowledge evaluation it’s the same logical structure as exporting an opinion to a trusted friend. It’s just that in this case the authority is your calculator and it’s widely known to be an expert in calculation. Indeed, it’s known to be pretty much infallible.

You believe that your friend the calculator is correct not because you’ve tried to verify every result it comes up with. You believe it’s correct because you trust all the engineers and scientists who have produced it and who also use calculators themselves.

Indeed, most of us would probably trust a calculator more than our own calculations, or that of the Pope. And there is a good reason for that – we have a lot of prior knowledge about whose opinion on this matter is reliable. And that is also relevant knowledge.

Therefore, an argument from authority can be better than an argument lacking authority if you take into account evidence for the authority’s expertise in the subject area.

Logical fallacies were widely used by the Greeks in their philosophical discourse. They were discussing problems like “Can a circle be squared?” But many of today’s problems are of an entirely different kind, and the Greek rules aren’t always helpful.

The problems we face today can be extremely complex, like the question “What’s the origin of climate change?” “Is it a good idea to kill off mosquitoes to eradicate malaria?” or “Is dark matter made of particles?” Most of us simply don’t have all the necessary evidence and knowledge to arrive at a conclusion. We also often don’t have the time to collect the necessary evidence and knowledge.

And when a primary evaluation isn’t possible, the smart thing to do is a secondary evaluation. For this, you don’t try to answer the question itself, but you try to answer the question “Where do I best get an answer to this question?” That is, you ask an authority.

We do this all the time: You see a doctor to have him check out that strange rush. You ask your mother how to stuff the turkey. And when the repair man says your car needs a new crankshaft sensor, you don’t yell “argument from authority.” And you shouldn’t, because you’ve smartly exported your primary evaluation of evidence to a secondary system that, you are quite confident, will actually evaluate the evidence *better* than you yourself could do.

But… the secondary evidence you need is how knowledgeable the authority is on the topic of question. The more trustworthy the authority, the more reliable the information.

This also means that if you reject an argument from authority you claim that the authority isn’t trustworthy. You can do that. But it’s here’s where things most often go wrong.

The person who doesn’t want to accept the opinion of scientific experts implicitly claims that their own knowledge is more trustworthy. Without explicitly saying so, they claim that science doesn’t work, or that certain experts cannot be trusted – and that they themselves can do better. That is a claim which can be made. But science has an extremely good track record in producing correct conclusions. Questioning that it’s faulty therefore carries a heavy burden of proof.

So. To use an argument from authority correctly, you have to explain why the authority’s knowledge is not trustworthy on the question under consideration.

But what should you do if someone dismisses scientific findings by claiming an argument from authority?

I think we should have a name for such a mistaken use of the term argument from authority. We could call it the fallacy of the “omitted knowledge prior.” This means it’s a mistake to not take into account evidence for the reliability of knowledge, including one’s own knowledge. You, your calculator, and the pope aren’t equally reliable when it comes to evaluating logarithms. And that counts for something.

The 2017 Edge Annual Question: Which Scientific Term or Concept Ought To Be More Widely Known?

My first thought when I heard the 2017 Edge Annual Question was “Wasn’t that last year's question?” It wasn’t. But it’s almost identical to the 2011 question, “What scientific concept would improve everybody’s cognitive toolkit.” That’s ok, I guess, the internet has an estimated memory of 2 days, so after 5 years it’s reasonable to assume nobody will remember their improved toolkit.

After that first thought, the reply that came to my mind was “Effective Field Theory,” immediately followed by “But Sean Carroll will cover that.” He didn’t, he went instead for “Bayes's Theorem.” But Lisa Randall went for “Effective Theory.”

I then considered, in that order, “Free Will,” “Emergence," and “Determinism,” only to discard them again because each of these would have required me to first explain effective field theory. You find “Emergence” explained by Garrett Lisi, and determinism and free will (or its absence, respectively), is taken on by Jerry A. Coyne, whom I don’t know, but I entirely agree with his essay. My argument would have been almost identical, you can read my blogpost about free will here.

Next I reasoned that this question calls for a broader answer, so I thought of “uncertainty” and then science itself, but decided that had been said often enough. Lawrence Krauss went for uncertainty. You find Scientific Realism represented by Rebecca Newberger Goldstein, and the scientist by Stuart Firestein.

I then briefly considered social and cognitive biases, but was pretty convinced these would be well-represented by people who know more about sociology than me. Then I despaired for a bit over my unoriginality.

Back to my own terrain, I decided the one thing that everybody should know about physics is the principle of least action. The name hides its broader implications though, so I instead went for “Optimization.” A good move, because Janna Levin went for “The Principle of Least Action.”

I haven’t read all essays, but it’ll be a nice way to start the new year by browsing them. Happy New Year everybody!

Physics is good for your health

Book sandwich
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Yes, physics is good for your health. And that’s not only because it’s good to know that peeing on high power lines is a bad idea. It’s also because, if they wheel you to the hospital, physics is your best friend. Without physics, there’d be no X-rays and no magnetic resonance imaging. There’d be no ultrasound and no spectroscopy, no optical fiber imaging and no laser surgery. There wouldn’t even be centrifuges.

But physics is good for your health in another way – as the resort of sanity.

Human society may have entered a post-factual era, but the laws of nature don’t give a shit. Planet Earth is a crazy place, full with crazy people, getting crazier by the minute. But the universe still expands, atoms still decay, electric currents still take the path of least resistance. Electrons don’t care if you believe in them and supernovae don’t want your money. And that’s the beauty of knowledge discovery: It’s always waiting for you. Stupid policy decisions can limit our collective benefit from science, but the individual benefit is up to each of us.

In recent years I’ve found it impossible to escape the “mindfulness” movement. Its followers preach that focusing on the present moment will ease your mental tension. I don’t know about you, but most days focusing on the present moment is the last thing I want. I’ve done a lot of breaths and most of them were pretty unremarkable – I’d much rather think about something more interesting.

And physics is there for you: Find peace of mind in Hubble images of young nebulae or galaxy clusters billions of light years away. Gauge the importance of human affairs by contemplating the enormous energies released in black hole mergers. Remember how lucky we are that our planet is warmed but not roasted by the Sun, then watch some videos of recent solar eruptions. Reflect on the long history of our own galaxy, seeded by tiny density fluctuations whose imprint still see today in the cosmic microwave background.

Or stretch your imagination and try to figure out what happens when you fall into a black hole, catch light like Einstein, or meditate over the big questions: Does time exist? Is the future determined? What, if anything, happened before the big bang? And if there are infinitely many copies of you in the multiverse, does that mean you are immortal?

This isn’t to say the here and now doesn’t matter. But if you need to recharge, physics can be a welcome break from human insanity.

And if everything else fails, there’s always the 2nd law of thermodynamics to remind us: All this will pass.

Math blind

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Why must school children suffer through so much math which they will never need in their life? That’s one of these questions which I see opinion pieces about every couple of months. Most of them go back to a person by name Andrew Hacker whose complaint is that:

“Every other subject is about something. Poetry is about something. Even most modern art is about something. Math is about nothing. Math describes much of the world but is all about itself, and it has the most fantastic conundrums. But it is not about the world.”

Yes, mathematics is an entirely self-referential language. That’s the very reason why it’s so useful. Complaining that math isn’t about some thing is like complaining that paint isn’t an image – and even Hacker concedes that math can be used to describe much of the world. For most scientists the discussion stops at this point. The verdict in my filter bubble in unanimous: mathematics is the language of nature, and if schools teach one thing, that’s what they should teach.

I agree with that of course. And yet, the argument that math is the language of nature preaches to the converted. For the rest it’s meaningless rhetoric, countered by the argument that schools should teach what’s necessary: necessary to fill in a tax return, calculate a mortgage rate, or maybe estimate how many bricks you need to build a wall along the US-Mexican border.

School curriculums have to be modernized every now and then, no doubt about this. But the goal cannot be to reduce a subject of education based on the reasoning that it’s difficult. Math is the base of scientific literacy. You need math to understand risk assessments, to read statistics, and to understand graphs. You need math to understand modern science and tell it from pseudoscience. Much of the profusion of quack medicine like quantum healing or homeopathy is due to people’s inability to grasp even the basics of the underlying theories (or their failure to notice the absence thereof). For that you’d need, guess what, math.

But most importantly, you need math to understand what it even means to understand. The only real truths are mathematical truths, and so proving theorems is the only way to learn how to lead watertight arguments. That doesn’t mean that math teaches you how to lead successful arguments, in the sense of convincing someone. But it teaches you how to lead correct arguments. And that skill should be worth something, even if Hacker might complain that the arguments are about nothing.

I thought of this recently when my daughters had their school enrollment checkup.

One of the twins, Lara, doesn’t have stereo vision. We know this because she’s had regular eye exams, and while she sees well on both eyes separately, she doesn’t see anything on the 3d test card. I’ve explained to her why it’s important she wears her eye-cover and I try to coax her into doing some muscle building exercises. But she doesn’t understand.

And how could she? She’s never seen 3d. She doesn’t know what she doesn’t see. And it’s not an obvious disability: Lara tells distances by size and context. She knows that birds are small and cars are large and hence small cars are far away. For all she can tell, she sees just as well as everybody else. There are few instances when stereo-vision really makes a difference, one of them is catching a ball. But at 5 years she’s just as clumsy as all the other kids.

Being math-blind too is not an obvious disability. You can lead a pleasant life without mathematics because it’s possible to fill in the lack of knowledge with heuristics and anecdotes. And yet, without math, you’ll never see reality for what it is – you’ll lead your life in the fudgy realm of maybe-truths.

Lara doesn’t know triangulation and she doesn’t know vector spaces, and when I give her examples for what she’s missing, she’ll just put on this blank look that children reserve for incomprehensible adult talk, listen politely, and then reply “Today I built a moon rocket in kindergarten.”

I hear an echo of my 5 year old’s voice in these essays about the value of math education. It’s trying to tell someone they are missing part of the picture, and getting a reply like “I have never used the quadratic formula in my personal life.” Fine then, but totally irrelevant. Rather than factoring polynomials, let’s teach kids differential equations or network growth, which is arguably more useful to understand the world.

Math isn’t going away. On the very contrary it’s bound to dramatically increase in significance as the social sciences become more quantitative. We need that precision to make informed decisions and to avoid reinventing the wheel over and over again. And like schools teach the basics of political theory so that children understand the use of democracy, they must teach mathematics so that they understand the use of quantitative forecasts, uncertainties, and, most of all, to recognize the boundary between fact and opinion.