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 eclipse

Above, a NASA photo of the solar eclipse of August 21.

The second before the sun went out we saw a wall of dark shadow come speeding at us. We no sooner saw it than it was upon us, like thunder. It roared up the valley. It slammed our hill and knocked us out. It was the monstrous swift shadow cone of the moon. I have since read that this wave of shadow moves 1,800 miles an hour. Language can give no sense of this sort of speed – 1,800 miles an hour. It was 195 miles wide. No end was in sight – you saw only the edge. It rolled at you across the land at 1,800 miles an hour, hauling darkness like plague behind it. Seeing it, and knowing it was coming straight for you, was like feeling a slug of anesthetic shoot up your arm. If you think very fast, you may have time to think, ‘Soon it will hit my brain.’ You can feel the deadness race up your arm; you can feel the appalling, inhuman speed of your own blood. We saw the wall of shadow coming, and screamed before it hit.” — Annie Dillard, 1982

I wish I had been there to see it.


Misquotes for Science

It’s a tough call, but the award for silliest statement at the March for Science has to go to the line “Dante said that the hottest places in Hell are reserved for those who remain neutral in times of moral crisis.” Dante never said anything of the sort, of course – the line is derived from something JFK said (“The hottest places in Hell are reserved for those who in time of moral crisis preserve their neutrality”), derived in turn from a chain of misquotes going back to Theodore Roosevelt. I’ve written before about Dante and Science, but suffice to say that in Dante’s Inferno, the worst regions are actually icy cold, and “neutrals” are not found there:

Please, let’s not have any “alternative facts” about Dante. The climate of the Inferno is important too.


In praise of the codex


Charles Emmanuel Biset, Still life with Books, a Letter and a Tulip

The codex (book with pages) has been with us for about 2,000 years now. Because of advantages like rapid access to specific pages, it gradually replaced the older technology of the scroll:

Christians seem to have been early adopters of the codex technology. The oldest known fragment of the Christian New Testament, papyrus P52, dated to around the year 130, is a small fragment of a codex of the Gospel according to John (with parts of verses 18:31–33 on one side of the page, and parts of verses 18:37–38 on the other):

In 2010, Google estimated that the total number of published books had reached 130 million. At times it seems that e-books are taking over from the printed codex format, but there is a friendliness to the printed book that would make me sorry to see it go. I am not the only one.

Robert Darnton, in The Case for Books: Past, Present, and Future, writes: “Consider the book. It has extraordinary staying power. Ever since the invention of the codex sometime close to the birth of Christ, it has proven to be a marvelous machine – great for packaging information, convenient to thumb through, comfortable to curl up with, superb for storage, and remarkably resistant to damage. It does not need to be upgraded or downloaded, accessed or booted, plugged into circuits or extracted from webs. Its design makes it a delight to the eye. Its shape makes it a pleasure to hold in the hand.

How true that is!


I ♥ science books!


Disasters in science #3

Engineers have a moral obligation to take great care with safety-related issues. As Kipling says, “They do not preach that their God will rouse them a little before the nuts work loose. They do not teach that His Pity allows them to leave their job when they damn-well choose.


Blue Jeans and Culture

An earlier post touched on the concept of “cultural appropriation.” This label is often applied inappropriately, because the world is more interconnected than most people realise. It has been that way for longer than most people realise (for example, some 4,000 years ago, tin from England was being traded across the Mediterranean sea for use in making bronze). And ideas go back further than most people realise.

As Michael Crichton says in his excellent novel Timeline, “Yet the truth was that the modern world was invented in the Middle Ages. Everything from the legal system, to nation-states, to reliance on technology, to the concept of romantic love had first been established in medieval times. These stockbrokers owed the very notion of the market economy to the Middle Ages. And if they didn’t know that, then they didn’t know the basic facts of who they were. Why they did what they did. Where they had come from.

Consider blue jeans, for example.

Blue jeans are dyed with indigotin, a chemical derived from the indigo plant, which has long been grown in India. But before someone says “cultural appropriation from India,” indigotin was traditionally derived in Europe from the woad plant (northern Britons painted their skins blue with woad). In China, a different plant was used. Essentially, the use of indigotin was a cultural universal. In Germany, where a culture of excellence in organic chemistry grew up during the 19th century, a practical method for making synthetic indigotin was developed at the BASF company in 1897, and the choice of plant became moot.


A cake of indigo dye (photo: David Stroe)

Blue jeans are made from denim, a fabric named after Nîmes in France. During the California gold rush, Levi Strauss, a Jewish-American businessman of German origin, teamed up with Jacob Davis, a Jewish-American tailor of Latvian origin, to make denim work clothing for miners. These blue jeans were strengthened by metal rivets – an idea due to Davis, patented in 1873.

So which culture produced blue jeans – Indian? French? German? Latvian? Jewish? American? One can only say that blue jeans were produced by human culture.


Illustration from the patent application