Thursday, January 31, 2019


No reason, I just like them. Roman griffin, possibly from a helmet, found attached to a German chieftain's standard in the Vimose bog.

Alexander lifted into the air by four griffins, a scene from the Alexander Romance; this is the Talbot Shrewsbury book, 15th century.

Gold ring from Phourni, Bronze Age Greece.

The ancient Persians were particularly fond of griffins. Column from Persepolis and relief from the Palace of Darius I at Susa.

Relief from Old Kingdom Egypt showing an assortment of demons. The oldest surviving depiction of a griffin comes from Egypt, dating to around 3100 BC, but a fusion of lions and eagles seems rather obvious to me so the idea may be much older.

Pebble mosaic from Sikyon, Greece, 350-300 BC.

Pitcher or aquamanile in the form of a griffin, from Nuremberg, Germany, 1425-1450 AD.

Restored fresco from the Minoan palace at Knossos.

Silver stater from Teos, c 500 BC.

Scythian felt applique from one of the frozen tombs of the Altai.

Byzantine relief, 1250-1300 AD.

Peter Thiel's Theory of Entrepreneurship

Scott Alexander reviews Zero to One, a book based on a course about entrepreneurship Thiel taught at Stanford some years ago. Most of the book, he says, is
less directly about the startup world, and more about deep social trends that good startup founders will have to buck. One such trend – which Thiel approaches in a lot of different equivalent ways – is the loss of belief in secrets. People no longer believe that there are important things that they don’t know, but which they could discover if they tried a little harder.

Past scientific discoveries came from a belief in secrets. Isaac Newton wondered why apples fell, thought “Maybe if I work really hard on this problem, I can discover something nobody has ever learned before”, and then set out to do it. Modern people aren’t just less likely to think this way. They’re actively discouraged from it by a culture which mocks stories like Newton’s as “the myth of the lone genius”. Nowadays people get told that if they think they’ve figured out something about gravity, they’re probably a crackpot. Instead, they should wait for very large government-funded programs full of well-credentialled people to make incremental advances.

Good startups require a belief in secrets, where “secret” is equivalent to “violation of the efficient market hypothesis”. You believe you’ve discovered something that nobody else has: for example, that if you set up an online bookstore in such-and-such a way today, in thirty years you’ll be richer than God. This is an outrageously arrogant claim: that you have spotted a hundred-billion-dollar bill lying on the sidewalk that everyone else has missed. But only people who believe something like it can noncoincidentally found great companies. You must believe there are lucrative secrets hidden in plain sight. . . .

Belief in secrets is connected to belief in one’s own reasoning abilities. Modern conventional wisdom says armchair reasoning never works; any idea you prove true in your head is useless until it’s been exhaustively tested in real life, and you’re more likely to get some other (true) idea out of the exhaustive testing than to validate your armchair speculation. As a corollary, the more steps in your proof, the less likely it is, since each one exponentially increases the error rate of your final conclusion. Since your armchair reasoning is useless, you are unlikely to ever discover a secret (except perhaps by chance, if you randomly do experiments no one else has ever done). The only thing that might not be useless is large institutions working together to gradually advance knowledge with lots of testing, who effectively buy many lottery tickets hoping one will pay off.
This fascinates me partly because it might be true to some extent about business but can, I think, lead to truly horrible thinking about politics. Of course it might be that billionaire entrepreneurs are mainly just lucky, not in the sense that they don't have good ideas or work hard but in the sense that other people have equally good ideas and work just as hard and the ones who become billionaires rather than just rich have simply won the lottery; but I can certainly see an appealing logic to what Thiel says.

Thiel is one of the world's leading libertarians, and also a great believer in social experiments. He is one of the main backers of the sea-steading movement. He assumes that these human-created islands would be libertarian paradises, but he has on occasion said that they will actually be laboratories in which people might try all sorts of different governments. Here we see the faith in armchair reasoning that Alexander highlighted: Thiel thinks some guy on an artificial island might just imagine a system of government as much better than any previous form as Amazon is better than Sears.

I, of course, think this is nonsense; I think that managing a society is a problem several orders of magnitude more complicated than anything done by Google, and that it is in fact a problem beyond the reach of human reason. All attempts to imagine a great form of government from scratch have failed; all successful revolutions preserve more than they destroy.

I say the only way to figure out how to govern a society is to look around the world and see what works. I acknowledge it is possible that some genius might one day come up with a radical social or political innovation that works brilliantly, but I consider it very, very unlikely.

Sea Smoke on Lake Michigan

A phenomenon of very cold mornings, shot by a friend from her apartment window.

Wednesday, January 30, 2019


In California Fog, by Kevin Drum

Accuracy vs. Correctness

The Babylon Bee:
Popular fact-checking site confirmed Wednesday they are debuting a new "Factually inaccurate but morally right" fact check result for claims they don't want to debunk because they coincide with Snopes editors' worldview.
The Babylon Bee may be the only funny conservative web site in the world, or at least the only one liberals ever laugh at.

Monday, January 28, 2019

Elite Capture

Elites across human history have been skilled at recruiting the top rebels into their own ranks, thereby blunting the threat of revolt. The latest prominent case is Greek Prime Minister Alexis Tsipras:
The 44-year-old Greek prime minister is barely recognisable as the leftwing firebrand who threatened to denounce Greece’s eurozone bailout, ban German politicians from visiting Athens and pull the country out of the euro if its creditors rejected his demands for debt forgiveness.

Four years after his first narrow election victory for his radical Syriza party, Mr Tsipras has become a surprising anchor of Greek financial discipline. His government is generating the sort of budget surplus that Athens’ creditors could once only have dreamt of. And he has reinvented himself as a southern European pragmatist, committed to being a co-operative EU partner while deepening relations with Washington in the interests of regional security.

“Tsipras now has a new international profile, that of the mature leader ready to incur political cost to carry out unpopular policies, whether it’s over Macedonia or the difficult economic reforms needed to keep Greece in the eurozone,” said Aris Hatzis, an Athens university professor of law and economics.
As a result, Tsipras is no longer popular and his party is expected to fall from power in the next election.

You can say, well, it's a good thing he failed to follow through on those threats because withdrawal from the Eurozone would have been a disaster for Greece. And maybe that is correct, although I think it is far from certain. But over the long run this sort of thing can breed toxic cynicism.

Consider the background to the revolution of Hugo Chavez in Venezuela: twenty years in which the leaders of both political parties called for reneging on the country's debts while out of power and then never did, in which anti-foreign, anti-banker, pro-people rhetoric never led to any changes in actual policies. Eventually the people got sick of it and fell for Chavez.

I think this is the big lesson for anyone who wants a world led by rational technocrats: if you persistently lie to and otherwise ignore the masses, they will turn to any available alternative, no matter how crazy.

Sunday, January 27, 2019

The Alnwick Poison Garden

Alnwick is the seat of the Dukes of Northumberland, one of the most famous and visited castles in the north of England. The oldest stonework goes back to not long after the Norman Conquest, but of course it has been rebuilt and enlarged many times.

These days the castle itself is a secondary attraction compared to the spectacular gardens, about which there is a story:
In 1995, Jane Percy became the Duchess of Northumberland, a county in northeastern England that stretches to the border with Scotland, after her husband's brother died unexpectedly. With the title came the Alnwick Castle, the traditional seat of the Duke of Northumberland (it also served as the setting for Hogwarts in the first two Harry Potter films). After the family took up residence in the castle, Percy's husband asked her to do something with the gardens, which at the time were a disused commercial forestry boasting nothing more than rows and rows of Christmas trees.

"I think he thought, 'That will keep her quiet, she’ll just plant a few roses and that’ll be it,'" the duchess says. But Percy did more than plant a few roses. In 1996, she hired Jacques Wirtz, a landscape architect who has worked with the Tuileries in Paris and the gardens of the French president's residence, to help reimagine the Alnwick Garden. Today, the gardens encompass 14 acres and attract over 600,000 visitors each year, making them one of North England's most popular tourist attractions.
I have long been fascinated by these stories married couples tell about their relationships, which so often fall into stereotypical patterns. I wonder, where does the stereotyping come in: is it the relationships themselves, or they way we talk about them? Both, I suppose; but which is more important? Do marriages really follow patterns, or is every relationship unique, and we render them commonplace so as to better communicate with others?

Anyway the ambitious duchess was not satisfied with an ordinary garden, and she went out of her way to make hers distinctive. As with the whirlpool fountain.

And especially with the poison garden.

This is a small garden that displays only poisonous plants, some of them very dangerous indeed, like deadly nightshade.

Others are only dangerous if you put a lot of work into refining and concentrating the poison, like the castor bean, from which ricin is made.

What a genius idea, and how pleasing that no busy-body bureaucrat has intervened to put a stop to it. (Yes, laburnum and laurel hedge can both be poisonous.)

John Dunkley

John Dunkley (1891-1947) was an untrained Jamaican artist who has lately gotten a lot of art world attention, including a major retrospective show at the American Folk Art Museum. (Banana Plantation, 1945)

Although Dunkley never took an art class he did study art on his own, and critics think he was influenced by William Blake and Henri Rousseau. (Back to Nature; the rest of these are not dated but they all seem to come from the 1930s and 1940s.

Dunkley was actually quite successful. His paintings were collected by elite Jamaicans who wanted something authentically black and anti-colonial. Politically Dunkley was a pan-Africanist and an admirer of Marcus Garvey. (Panama Scenery)

R and S Going to Market.

Spider's Web. I wonder if the strange lighting -- the current exhibit is called Neither Day nor Night -- relates to dreams or visions. It's certainly very striking.

View of this exhibition, showing one of his sculptures.

Saturday, January 26, 2019

The Dream

Sam explains about the secret entrance to the castle.

Gilly: How do you know all this?

Sam: I read about it in a very old book.

Gilly: You know all that, just from staring at marks on paper? You're, like, a wizard.

--Game of Thrones

Friday, January 25, 2019

Death and the Economy

You might think that death rates would go up in bad economic times and down in good times. But for the past 120 years the opposite has been true. Raw death rates fall in bad times, including the Great Depression and the 2008-2009 recession.

This is somewhat of a puzzle, especially since we know that suicide rates go up in bad times.

The effect is not very large but a century of sociological study has confirmed that it is real in North America, Europe, and Japan. Why?

Some possible factors:
There are many potential contributors. One of the more predictable perks of a poor economy is fewer job-related accidents. The most-experienced workers are the ones most likely to keep their jobs during a recession, and slower production can allow for more attention to safety.

People also tend to drive less, which translates to fewer traffic accidents. And fewer vehicles on the road might also help to explain why air quality is better. “When employment pops up, so do things related to pollution — commerce, industry, trucks on the road,” says Mary Davis, an environmental-policy specialist at Tufts University in Medford, Massachusetts. The air-quality connection might also help explain why studies have also linked recessions to reduced cardiovascular and respiratory problems, as well as infant mortality.
(I doubt air quality is as much of an issue now, but remember that before 1970 more economic activity meant burning more coal in plants without scrubbers, meaning pollution might get a lot worse.)
Researchers have suggested other explanations. In addition to dirty air, cardiovascular issues are known to be exacerbated by stress, a poor diet, lack of exercise, drinking alcohol and smoking tobacco. Working less and having less money to spend could translate into more sleep, exercise and home-cooked meals, as well as less job-related stress and less money for pints of beer and cigarettes. There is some evidence that this logic plays out. Based on data from 1987 through to 2000, Ruhm found that smoking and excess weight declined during economic downturns, whereas leisure-time physical activity increased. When Iceland’s economy crashed in 2008, and the price of imported goods such as tobacco and alcohol rose, citizens consumed fewer of those products. And US data from 1977 to 2008 showed that a husband’s unemployment reduced how much alcohol his wife drank, on average, irrespective of her own employment status. Even people who fear job loss, but remain fully employed, Catalano’s research suggests, might still cut back on alcohol to seem a more indispensable employee.
The impact of work on our physical and mental health is decidedly mixed. Long-term unemployment causes depression, but when people are really busy (as they are more likely to be in economic booms) they are stressed and more likely to grab bad meals on the run.

So we can do nothing and slide into depression and die that way, or work ourselves to death. . . .

Thursday, January 24, 2019

Church of Santa María, Quintanilla de las Viñas

In 1921 a Spanish priest nmed Don Bonifacio Zamora was out for a walk in the countryside near Burgos when he noticed a stone ruin hidden by dense brush.

No historian himself, Don Zamora nonetheless realized that he had found something amazing. He began contacting the authorities but they were uninterested in the opinions of an ignorant rural priest and ignored him for years. Don Zamora eventually interested some university professors in his discovery, notably the German scholar Helmut Schlunk. The experts verified Don Zamora's intuition that he had found a historic site of great significance and the church was declared a historic monument in 1929.

What stands on the site is only a small part of the original church, apparently modified to be used as a hermitage (a retreat for monks who found their monasteries too rowdy) after the nave had fallen down or become uninhabitable.

While the German experts verified that this was a historic site and helped arranged its preservation, they dragged the church into a new controversy. They insisted that this was a work of the Visigothic period before the Arab conquest, most likely the 7th century. There is no written record of a church in this location before 1038, and there has been no decisive archaeological evidence for the early date either, so many experts think this is an 11th-century church. The question remains unresolved.

The glory of the place is the stone carving, in a wonderfully distinctive style.


And the wonder of these carvings explains why, back in 2004, two Spanish thugs drove out to the site with a crane and lifted two carvings into their truck, thinking they had struck it rich. But stolen art is difficult to sell – it typically fetches only 5 to 10 percent of its market value – as the thieves discovered. After passing through a couple of intermediaries they were sold for about 50,000 pounds to a British lord, who installed them in his garden.
Somebody with a keen eye saw the “garden ornaments” for sale and thought they was much more to them. He alerted the Art Detective, private investigator Arthur Brand who recovers looted cultural material and stars in a TV show in the Netherlands dedicated to his exploits. Brand traveled to England to follow up, only to find that his informant had just died. His wife only knew a man named “Tony” was connected to the stones. All she had was his first name and a description of him.
Nonetheless Brand eventually located Tony and through him found the reliefs, reclaiming them from their highly embarrassed owners, who had not a clue what they were.

Which I think is a story worthy of this wonderful place.

George Will v. Lindsay Graham

George Will turns his contempt for Donald Trump onto a new target, Trump's new ally Lindsay Graham:
In 2015, Graham said Donald Trump was a “jackass.” In February 2016, he said: “I’m not going to try to get into the mind of Donald Trump, because I don’t think there’s a whole lot of space there. I think he’s a kook, I think he’s crazy, I think he’s unfit for office.” And: “I’m a Republican and he’s not. He’s not a conservative Republican. He’s an opportunist.” Today, Graham, paladin of conservatism and scourge of opportunism, says building the border wall is an existential matter for the GOP: “If we undercut the president, that’s the end of his presidency and the end of our party.” Well.
After marveling that any Republican thinks the party of Lincoln could be ended by disloyalty to Trump, Will continues:
During the government shutdown, Graham’s tergiversations — sorry, this is the precise word — have amazed. On a recent day, in 90 minutes he went from “I don’t know” whether the president has the power to declare an emergency and divert into wall-building funds appropriated by Congress for other purposes, to “Time for President . . . to use emergency powers to build Wall.” The next day, he scrambled up the escalation ladder by using capitalization: “Declare a national emergency NOW. Build a wall NOW.” Two days later, he scampered down a few rungs, calling for his hero to accept a short-term funding measure to open the government while wall negotiations continue. Stay tuned for more acrobatics.

But stay focused on this: Anyone — in Graham-speak, ANYONE — who at any time favors declaring an emergency, or who does not denounce the mere suggestion thereof, thereby abandons constitutional government. Yes, such a declaration would be technically legal. Congress has put on every president’s desk this (to adopt Justice Robert Jackson’s language in his dissent from the Supreme Court’s 1944 Korematsu decision affirming the constitutionality of interning of U.S. citizens and noncitizens of Japanese descent) “loaded weapon, ready for the hand of any authority that can bring forward a plausible claim of an urgent need.” Or an implausible one. However, an anti-constitutional principle would be affirmed. The principle: Any president can declare an emergency and “repurpose” funds whenever any of his policy preferences that he deems unusually important are actively denied or just ignored by the legislative branch.
The partisan leanings of Senators and Representatives used to be somewhat balanced by loyalty to their own institutions, but over the past 25 years this seems to have completely disappeared. Leaving us, as Will says, with nothing but loyalty to the party and its leaders of the moment.

Tuesday, January 22, 2019

The Dating App Ghostwriter

Ms. Golden, 43, has developed these no-fly lists in her four years as a dating app ghostwriter. For $2,000 a month, she swipes, chats and charms, impersonating her clients. Once she has earned a client a date, she tags them in and becomes a more traditional dating coach, reviewing each encounter in detailed post-mortems, helping to guide their next moves. Some clients disclose to their dates that they have used Ms. Golden’s services, and others do not. . . .

Tone is essential to Ms. Golden’s — and her clients’ — success. She learns to imitate their conversational styles through the use of an eight-page intake form that includes specific questions: How do you take your coffee? Have you ever “swam with dolphins or stingrays or enormous turtles”?

By the time a potential client has answered those questions and had an hourlong introductory conversation, Ms. Golden thinks she can mimic them convincingly enough — down to whether they would type “gonna” or “going to” — to start chatting.

Ms. Golden subscribes to a less-is-more mind-set, and much of the work she does is in how little she says. She will not get caught in volleys of conversation, and judges prospective dates who do so.

“They should be wondering more about me, and I’m not going to give it all to them right then and there,” she said. “When I’m messaging someone and they respond right away I’m like, chill out, eager beaver.”

Wolf Moon? What Wolf Moon?

As America got all excited about the Super Wolf Blood Moon, I, the resident pedant, asked myself, "In what culture is the January moon called the Wolf Moon anyway?" I mean, I'm a huge folklore nerd, and I can't remember hearing of the Wolf Moon before.

It isn't Germanic; the old German calendars call this either "Winter Month" or "After Yule." It isn't Celtic. It isn't Roman or Greek or Chinese.

All the popular web sites ginning up enthusiasm for the Super Wolf Blood Moon refer to the Old Farmer's Almanac, which is a dubious source but does include some old American lore drawn from Indians. American Indians certainly did name the moons. However, none of the versions I am familiar with have a Wolf Moon in the winter. Most of the eastern tribes called it something like Ice or Cold or the Sun is Weak or The Moon of Staying Inside. So I did a bit of searching and found this site that lists a whole bunch of Native American calendars (e.g., Choctaw, Moon When the Old Fellow Spreads the Brush; Pueblo, Moon of the Cedar Dust Wind), but precious little about wolves. The Potawotami call the moon after midwinter the Bear Moon, I suppose because that was when they hunted hibernating black bears; in other calendars, and the ethnography of the Cherokee, that is February. The only calendar on this site that mentions wolves is a generic "Sioux" list that has Wolves Run Together for January, but since Sioux is a name for a language family, not a particular tribe or tradition (Lakota is Hard Moon), I am skeptical of the provenance.

This astronomy site says Wolf Moon is Ojibwa, but all the other sources I have found say their January moon was called The Great Spirit Moon, so again I am dubious.

I am not denying that some Native people somewhere, sometime called the January moon the Wolf Moon, but obviously it was not the most common name. Many more people named this month for its most obvious characteristic, the temperature. This whole business of the Wolf Moon seems to have been gotten up by nineteenth-century publishers to sell almanacs.


Monday, January 21, 2019

Troublesome Immigrants from Africa to Europe: the Golden Jackal

Fascinating article by James Gorman in the Times about the golden jackal, a 20-pound predator native to Africa and the Middle East that has been spreading into Europe since the wolves were nearly exterminated in the 1800s. The spread has accelerated in recent decades and now there are more than 100,000 jackals in Europe, compared to fewer than 20,000 wolves. They are most common in the Balkans, especially Bulgaria and Greece, but they have been spotted across the continent.

I guess the jackals are following the same path as coyotes in North America. Their smaller size allows them to survive more easily among people, and the absence of wolves (who hunt and kill both coyotes and jackals) leaves a predatory niche open for them to exploit.

Sunday, January 20, 2019

The Noblest Pleasure

The noblest pleasure is the joy of understanding.

- Leonardo da Vinci

Walter Isaacson, "Leonardo da Vinci"

Walter Isaacson's Leonardo da Vinci (2017) might be the best work of history I have read in the past year. I approached this book with trepidation, because Isaacson is not a historian. He is a technology groupie whose previous biographies have focused on much more modern characters like Steve Jobs, Henry Kissinger, and Albert Einstein, and I feared that without sufficient knowledge of the sixteenth century he would get everything wrong. He did not. He put in the effort to learn enough about Renaissance Italy to put Leonardo in his context, and the result is a terrific book.

Isaacson approaches Leonardo mainly through his notebooks. This is probably the best way for a biographer to proceed, because it is only in the notebooks that Leonardo's distinctiveness really emerges. Yes, he did a handful of amazing paintings, but in an era when other men did equally amazing paintings. His modern fame derives from his polymorphic genius. One might even say that it derives from a belief in genius as a powerful force in itself; it is as an exemplar of genius and a proof that a genius is a recognizable and important thing that Leonardo looms in our consciousness.

We know about Leonardo's ideas mostly from his notebooks. Very little that he imagined was ever published in any other form, let alone actually constructed, so if the notebooks had been lost, so would all record of his genius. Leonardo was a compulsive sketcher and note-taker, and scholars think he created about 13,000 pages of notebooks, more than 7,000 pages of which survive. It makes me wonder; how many other people were creative in this same way, but we don't know because their notebooks don't survive?

We can certainly see that Leonardo was a man of his time, interested in things that also fascinated his contemporaries. For example, perspective in vision and painting, one of the many topics about which Leonardo considered writing a book that he never finished.

Leonardo da Vinci (1452-1519) was certainly a remarkable person. He was the illegitimate son of a provincial lawyer, with no great prospects but on the other hand without any pressure to fill his father's shoes. Since he showed an early talent for art he was apprenticed at he age of 14 to Verrocchio, who ran one of the top artistic workshops in Florence. Since Leonardo's own lifetime art lovers have made a game of guessing which bits of Verrocchio's paintings were by Leonardo, and while some of those guesses must be right, I don't think any are certain. Leonardo was certainly developing as an artist, as the teenage drawing above shows.

Leonardo began completing his own commissions around 1480. He was already a hanger on of the unofficial Medici court -- at that time Florence was a Republic, and the Medici its first citizens -- where he played music and sang as well as painting. At the court he presumably had his first exposure to classical learning, and his first experience of being snobbed off as a rustic because he did not know Latin or anything about the ancient world. Leonardo's immediate reaction was to denounce book learning and to proclaim that experience was the only real source of knowledge. As he got older he began to see some value in scholarship and tried to learn Latin, but he was never very well educated by the standards of his time.

In 1482 Leonardo moved from Florence to Milan, where he entered the service of the mercenary captain turned ruler Ludovico Sforza. Sforza was a thug but the atmosphere of the court agreed with Leonardo. He was already bored with painting and longed to stretch his talents in other directions, and he hated all the committee meetings and expense audits that went with working for a Republic. One of the best things Isaacson does in his book is to show the importance of the connections that Leonardo made to other artists and intellectuals in Milan. For example, the famous drawing of Vitruvian Man emerged from a collaboration with two other men to design a new crossing tower for Milan's cathedral. While working on their design the three men discussed the ideas of the ancient Roman writer Vitruvius, who taught that the proportions of a building should reflect those of the human body. The three men discussed how to design a church according to these principles and all three produced their own drawings of a perfectly proportioned body for use in making the calculations. Leonardo's drawing is of course the best, but it was through working with other men that he came to understand this issue and develop his own version.

To me the most extraordinary thing about Leonardo was his ability to *see.* His drawings are more accurate than other people's partly because he was better at seeing what was actually there rather than what he expected.

My favorite example of Leonardo's amazing eye concerns the trajectory of canon balls. In Leonardo's day the path of a canon ball was usually drawn like this, two straight line segments connected by a curve.

Leonardo realized that this was not so, that in fact a body in flight traces out the curve we call a parabola. Leonardo knew very little math -- he may not even have known the word parabola -- and anyway the first person to actually derive this curve mathematically was Galileo. But Leonardo could see it.

In fact Leonardo later went even farther than Galileo, because he realized -- again, just from seeing canon balls fly by -- that the actual trajectory was not a perfect parabola because it was distorted by air resistance, making the second half shorter. This was a calculation nobody could make until Newton's time, but Leonardo's eye was centuries ahead of the mathematicians.

Isaacson devotes two chapters to Leonardo's work in anatomy, and I found these sections fascinating. Working together with Marcantonio della Torre, a professor at the University of Padua, Leonardo carried out a long series of dissections of human corpses and prepared an amazing set of anatomical drawings. Their goal was to publish these results in the form of a large, expensive book that would set a new standard for anatomy. And they really might have done it, except that della Torre died of the plague and Leonardo ended up dropping the project, as he did so many others. It was left to Andreas Vesalius to publish the new learning that was being developed in Italy as a result of dissecting human bodies, in 1525. This was a loss, because Leonardo's drawings were better, and in a couple of crucial cases more accurate.

Which brings me to another thing about Leonardo, the foreshadowings of future science that people have gleaned from his notebooks. According to Isaacson, Leonardo wrote a detailed description of the aortic valve in the heart that correctly explained the mechanism that closes it between beats, a discovery that had to be remade in the 1960s. This one was new to me but there are others. The most famous is his statement that the air on top of a bird's wing is thinner than the air below it, and that this is part of what holds up birds in flight; now we call this Bernoulli's principle.

This again gets us back to those 7,000 pages of notebooks. It happens often in science that the person who gets the credit for the discovery is not the first one to have the insight, but the one who follows up in detail and publishes the results. A famous example is that Wilhelm Roentgen was not the first person to notice that something coming from radium clouded photographic film, he was the first one to follow up with a program of experiments on what we now call x-rays instead of just deciding to keep the film away from the radium. So if we had voluminous notebooks from thousands of other clever, scientifically inclined people, how many of their random jottings would look like science decades ahead of its time? On the other hand we do have thousands of pages of notes from Newton and they're mostly about the Bible.

Leonardo's notebooks are simply a riot of exploration and invention. They are full of machines, some practical and many more completely absurd. They explore the flight of birds, the movements of water, the expression of emotions on the face, the physics of falling bodies, the growth of plants, so many things that not even a 500-page biography can begin to discuss them all.

Leonardo is a fascination and a puzzle, a great painter, an even better draftsman, an extraordinary observer, a restless imagination, a procrastinator on an epic scale who started far more things than he finished. Walter Isaacson's book is a great place to begin getting to know him.