On having multiple hypotheses which all fit the data

For every fact there is an infinity of hypotheses.” – from Robert Pirsig, Zen and the Art of Motorcycle Maintenance


‘I will read the inventory… First item: A very considerable hoard of precious stones, nearly all diamonds, and all of them loose, without any setting whatever… Second item: Heaps and heaps of loose snuff, not kept in a horn, or even a pouch, but lying in heaps… Third item: Here and there about the house curious little heaps of minute pieces of metal, some like steel springs and some in the form of microscopic wheels… Fourth item: The wax candles, which have to be stuck in bottle necks because there is nothing else to stick them in… By no stretch of fancy can the human mind connect together snuff and diamonds and wax and loose clockwork.’

‘I think I see the connection,’ said the priest. ‘This Glengyle was mad against the French Revolution. He was an enthusiast for the ancien regime, and was trying to re-enact literally the family life of the last Bourbons. He had snuff because it was the eighteenth century luxury; wax candles, because they were the eighteenth century lighting; the mechanical bits of iron represent the locksmith hobby of Louis XVI; the diamonds are for the Diamond Necklace of Marie Antoinette.’

Both the other men were staring at him with round eyes. ‘What a perfectly extraordinary notion!” cried Flambeau. “Do you really think that is the truth?’

‘I am perfectly sure it isn’t,’ answered Father Brown, ‘only you said that nobody could connect snuff and diamonds and clockwork and candles. I give you that connection off-hand. The real truth, I am very sure, lies deeper.’

He paused a moment and listened to the wailing of the wind in the turrets. Then he said, ‘The late Earl of Glengyle was a thief. He lived a second and darker life as a desperate housebreaker. He did not have any candlesticks because he only used these candles cut short in the little lantern he carried. The snuff he employed as the fiercest French criminals have used pepper: to fling it suddenly in dense masses in the face of a captor or pursuer. But the final proof is in the curious coincidence of the diamonds and the small steel wheels. Surely that makes everything plain to you? Diamonds and small steel wheels are the only two instruments with which you can cut out a pane of glass.’

The bough of a broken pine tree lashed heavily in the blast against the windowpane behind them, as if in parody of a burglar, but they did not turn round. Their eyes were fastened on Father Brown. ‘Diamonds and small wheels,’ repeated Craven ruminating. ‘Is that all that makes you think it the true explanation?’

‘I don’t think it the true explanation,’ replied the priest placidly; ‘but you said that nobody could connect the four things. The true tale, of course, is something much more humdrum. Glengyle had found, or thought he had found, precious stones on his estate. Somebody had bamboozled him with those loose brilliants, saying they were found in the castle caverns. The little wheels are some diamond-cutting affair. He had to do the thing very roughly and in a small way, with the help of a few shepherds or rude fellows on these hills. Snuff is the one great luxury of such Scotch shepherds; it’s the one thing with which you can bribe them. They didn’t have candlesticks because they didn’t want them; they held the candles in their hands when they explored the caves.’

‘Is that all?’ asked Flambeau after a long pause. ‘Have we got to the dull truth at last?’ ‘Oh, no,’ said Father Brown.

As the wind died in the most distant pine woods with a long hoot as of mockery Father Brown, with an utterly impassive face, went on: ‘I only suggested that because you said one could not plausibly connect snuff with clockwork or candles with bright stones. Ten false philosophies will fit the universe; ten false theories will fit Glengyle Castle. But we want the real explanation of the castle and the universe.” – from G. K. Chesterton, “The Honour of Israel Gow


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The R100 and the R101

An instructive saga in the history of engineering is the story of the British airships R100 and R101. As part of a grand social experiment, the R100 was built by private industry (it was designed by Barnes Wallis), while the R101 was built by the British government (specifically, by the Air Ministry, under Lord Thomson). The R100 worked fine, and made a test flight to Canada in August 1930 (the trip took 78 hours). Here is the R100 over a Toronto building:

The R100 was huge. Here is a size comparison of the R100 (219 m long) and an Airbus A380 (73 m long):

While the government-built R101 used servo motors to control its gigantic rudder, the R100 team had worked out that the rudder could actually be operated quite easily by hand, using a steering wheel and cables. The government-built R101 was beset by poor choices, in fact. It contained overly heavy engines, a steel frame, and too much dead weight overall. After construction, the R101 had to be lengthened by inserting a new 14-metre section in the centre, in order to increase lift. This alteration caused a number of problems. Its design also allowed the internal hydrogen-filled gasbags to chafe against the frame, there were serious problems with the outer covering, and several “innovative” design ideas were never properly tested.

There was enormous political pressure for the R101 to fly before it was ready to do so. On the evening of 4 October 1930, it departed for India with a crowd of VIPs on board. It never arrived, crashing in bad weather over France, and bursting into flames. The disaster led to the R100 also being grounded, and the British government abandoned any thoughts of flying airships (as the rest of the world was to do after the Hindenburg disaster).

There are all kinds of lessons to be drawn from the saga of the R100 and the R101. One of them is that optimism is not a viable strategy for safety-critical engineering. Another is that engineers test things. As Kipling says, “They do not preach that their God will rouse them a little before the nuts work loose.” A third is that risky designs and fixed deadlines simply do not mix.


World Solar Challenge: doing media right

I’ve often pointed out that a solar car team is more like a startup company than anything else. A little like the early days of Google, really. The main product (the solar car, the search engine) is a gigantic money sink, and any cash coming in relates to something else (sponsorship, advertising). Overall success requires multiple skill sets working together. In particular, making sponsorship work requires an excellent media team (as well as a car fast enough to generate lots of good news). A number of teams have a track record of doing this well – Twente, for example, and Punch.


Deufol Technics packs Punch’s car and gear yesterday

An important example of sponsorship relates to transport. Here, the team acts as a kind of giant billboard for a tricky logistics problem handled well. This year, Punch provided a textbook example of superb media handling on this topic:

‘Voor mij is het de eerste keer dat ik voor zo een uitdaging sta,’ zegt logistiek manager Pieter Galle uit Leuven. ‘Het batterijpakket versturen is de grootste uitdaging voor het team. De batterijcellen die wij gebruiken zijn vaak niet toegelaten op vluchten. Om deze toch te kunnen versturen moeten er veel veiligheidsmaatregelen getroffen worden. Gelukkig heeft DHL Global Forwarding, in samenwerking met Deufol als verpakker van de goederen en batterijen alles tot in de puntjes kunnen regelen, zodat wij ons met het team volledig op het wereldkampioenschap konden concentreren.’” (Translation: “‘It’s the first time I’ve faced a challenge like this,’ says logistics manager Pieter Galle from Leuven. ‘Transporting the battery pack was the biggest challenge for the team. The batteries we use are often forbidden on flights. To be able to send them, many safety measures need to be taken. Fortunately, DHL Global Forwarding, in cooperation with Deufol our packer, has managed all the details, making it possible for us to focus our attention on the world championship.’”)

And Pieter Galle wasn’t just engaged in hyperbole there – transporting lithium battery packs really is tricky. In 2015, and again this year, there have been horror stories involving battery packs. I should also point out that some good photos really help the sponsorship game too, like these from Twente this year, or this one from Michigan, or this one from Nuon in 2015:


Nuon’s 2015 flightcase being loaded (photo: Jorrit Lousberg)

Another important sponsorship category relates to the team’s university. Here Western Sydney provides an excellent example, with their 2015 car being part of a major university rebranding exercise:


Western Sydney University’s 2015 car (photo: A. Dekker)

Michigan always does a great job of this during the American Solar Challenge. Their media team generates local news coverage everywhere they go. And the University of Michigan can afford to take the long view. If a 12-year-old boy or girl somewhere in rural America gets excited by the car, and decides to study engineering at Michigan one day, that’s a win. And not just for the university – if the sponsorship money keeps rolling in, the cars keep rolling on, and the fans can keep watching.


Killer robots: it’s not the AI that’s the problem

In a recent open letter, Tesla’s Elon Musk and others called for a ban on autonomous weapons, saying “Lethal autonomous weapons threaten to become the third revolution in warfare. Once developed, they will permit armed conflict to be fought at a scale greater than ever, and at timescales faster than humans can comprehend. These can be weapons of terror, weapons that despots and terrorists use against innocent populations, and weapons hacked to behave in undesirable ways. We do not have long to act. Once this Pandora’s box is opened, it will be hard to close.

Yet autonomous weapons are already with us, after a fashion. And artificial intelligence isn’t actually the biggest problem.

A bullet, during the second or so that it is in flight, autonomously follows the laws of physics. But the world is not likely to have changed much during that time. If shooting the bullet was appropriate, that will still be true when it hits. A cruise missile can fly for several hours, and home in on a precise spot, specified by GPS coordinates – although things may have changed during those hours of flight.

Smarter again is a heat-seeking or radar-guided missile, which can home in on an aircraft, even one doing it’s best to evade the threat – yet it cannot distinguish passenger aircraft from military aircraft. The next step up are systems guided by IFF, which can distinguish friend from foe. After that comes the kind of AI that Elon Musk is talking about.

The ultimate extreme is the “Menschenjäger” of Cordwainer Smith’s 1957 short story “Mark Elf.” The Menschenjägers were built by the “Sixth German Reich” to seek out and kill their non-German enemies (whom they could infallibly detect by their non-German thoughts). Being virtually indestructible, the last Menschenjäger had travelled around the planet on this mission 2328 times by the time the story is set. Since no Germans were alive at that point, there was nobody left to shut it down.

The real problem with the Menschenjägers was not their AI, but their persistence in time. A similar problem arises with that most stupid of autonomous weapons, the landmine. Sown in their tens of millions, landmines continue to kill and maim for decades after the war that buried them is over.

It isn’t really a matter of whether the weapon has AI or not – it’s whether the weapon has an off switch or a self-destruct mechanism. No weapon should keep on pointlessly killing people.


The demise of the Western?

I recently came across a discussion on the demise of the Western genre. Where did all the great Western novels and movies go?

But has there actually been a demise? For data, I turned to rottentomatoes.com, who have a list of the top 66 Western films, based on movie critic reviews. Their list is headed by The Treasure of the Sierra Madre (1948), The Good, the Bad, and the Ugly (1966), High Noon (1952), The Searchers (1956), Once Upon a Time in the West (1968), True Grit (2010), The Wild Bunch (1969), A Fistful of Dollars (1964), Unforgiven (1992), and Sweetgrass (2009).

This histogram shows an increasing number of Western films over time:

But this is not the full story. Being based on movie reviews, the list is biased toward recent films, plus some “greats” of the past. In the histogram, colour shows film rating, with dark colours indicating higher ratings. Many of the recent films are clearly mediocre. Plotting the top 20 films tells a clearer story – there are about 2 good Western films each decade (except for the 80’s), with a peak of 8 during the 60’s:

The 60’s peak contains 3 Sergio Leone films, being composed of The Good, the Bad, and the Ugly (1966), Once Upon a Time in the West (1968), The Wild Bunch (1969), A Fistful of Dollars (1964), The Man Who Shot Liberty Valance (1962), the original True Grit (1969), The Magnificent Seven (1960), and Butch Cassidy and the Sundance Kid (1969). Perhaps that was a golden age for the genre.


When the towers fell


The World Trade Center towers (photo: Carol M. Highsmith)

I continue to see bizarre and ill-informed conspiracy theories on the Internet about the 2001 collapse of the World Trade Center towers (above). This is in spite of the detailed investigations of, and voluminous reports on, the event.


Steel softens at temperatures well below the melting point of 1400°C

In fact, it has long been known that structural steel buildings like the World Trade Center can collapse due to fire. In 1967, the structural steel roof of McCormick Place in Chicago collapsed because of softening due to a fire. This collapse began only about 30–45 minutes after the fire was reported.


The World Trade Center under construction (photo: Eric Shaw White)

In the case of the World Trade Center, this fundamental problem with structural steel was combined with building-specific design flaws. Still, in my view, concrete construction is simply safer. Concrete resists fire far better than steel, and locating fire escapes inside a thick concrete core assists evacuation, should that be needed. The 9/11 conspiracy theories are just silly, though.


A concrete tower under construction in Australia (photo: Erin Silversmith,)


Gender and glaciers?

There has been some controversy about the 2016 NSF-funded paper “Glaciers, gender, and science: A feminist glaciology framework for global environmental change research” (see here for a detailed analysis). The paper refers, inter alia, to the Forbes/Tyndall debate of the century before last (although I believe it is misinterpreting that saga). But, interesting as that episode was in the history of science, it has little to say about the epistemology of modern glaciology. In the 1800s, observing glaciers required extensive (perhaps even “heroic”) mountain climbing. Today, remote sensing methods and computer models are also important, and we understand glaciers much better than either Forbes or Tyndall did.

I don’t think that the gender studies lens adds anything to our understanding of glaciers. And I suspect that Elisabeth Isaksson, Moira Dunbar, Helen Fricker, Julie Palais, Kumiko Goto-Azuma, or Jemma Wadham would not think so either. Nor are race relations particularly important in studying ice. And as to “alternative ways of knowing,” I would prefer to stick with the scientific method – it’s worked very well so far (didn’t we just have a march against “alternative facts”?). Indeed, to subordinate science to the modern politicised humanities would be to abandon the concept of scientific truth, and to make it impossible to gain widespread agreement on the crises currently facing humanity.