Darwin in Old Age

I have just posted a video about what Darwin might have thought about old age. He walked on his thinking-path (the sandwalk) every day that he could even in old age. He was pretty much an invalid when he died, but not as much of an invalid as he would have been had he not walked on his thinking path so often.

First, in the video, Darwin speculates on why walking improved his thinking. I have already summarized this in an earlier essay. Gentle walking increases blood flow to the brain. Also, thinking, like walking, is a series of steps.

Second, in the video, Darwin speculates on why old age evolved. Humans are unique among animals in having decades of post-reproductive life span. One explanation is that natural selection has provided us with whatever we need to be young, but not whatever we need to be old. But if old age is just the dumping ground of bad genes and defective body parts, why hasn’t evolution gotten rid of it?

The more likely reason that humans grow old, rather than just dying, is that old people provide important benefits to their offspring and to their tribe. Old people are repositories of knowledge and wisdom (well, knowledge, anyway) especially before books and AI. Us old people know things that young people haven’t even thought to ask about. Also, old people help to take care of the grandkids while the parents are searching for food or status. This is also the time when old people can pass on a lot of culturally important information to later generations. Finally, old people may not travel very far but they can forage for food near the camp.

Old age doesn’t seem quite so bad when Darwin explains it to you.

The Thinking, Walking Biped, part eight. Famous Nature Walks: Henry David Thoreau

Probably every American student has had to read something by Henry David Thoreau. His literary immortality is thus guaranteed forever. Pretty good for a man who never had a steady job. He published a few books, gave a few talks, and walked for (he says) four hours every day as he lived out his life in Concord, Massachusetts during the middle nineteenth century. He was one of many writers who walked a lot; Thoreau mentions William Wordsworth as a writer who walked. He was a friend of (and, I suspect, a dependent upon) Ralph Waldo Emerson.

Thoreau is most famous for living out in the woods (on Emerson’s land) in a little hut that he built himself, at very little expense near the shore of Walden Pond. In case you think he lived in the hut all of his life, this is not true: he only lived there a couple of years. He just wanted to prove that it could be done.

I thought I would find a well-thought-out explanation of how and why he walked in his essay Walking. Given the essay title, it was not an unreasonable thing to expect. But in this essay, Thoreau actually had very little to say about walking other than that he would start off with no clear destination in mind and usually find himself heading southwest “toward Oregon” (which is not southwest of Concord).

But maybe this is the point. He would start walking with no particular topic to think about or problem on his mind. He would wait until he saw something that made him think, and then he would write about it later. That’s what I do, only I do not have a very good memory, so I make notes on my cell phone to remind me what I was supposed to write about. Thoreau was very observant, although (or because) he did not know what to observe.

He noticed patterns that others overlooked, especially Emerson. Emerson thought in big brush strokes and ignored details (or, in some cases, made them up). It was the details that mattered to Thoreau. As I walk around in French forests, I notice that the wild cherries ripen first, then the wild blackberries a couple of weeks later, and the wild dewberries last of all. Blackberries and dewberries look enough alike that it is easy to mistake one for the other. Thoreau had to notice the seasonal patterns of flowers and fruits, as he was passionate about eating wild fruits, especially huckleberries. I also eat wild fruits on my walks, cherries first in the summer, then blackberries, then dewberries toward autumn. Thoreau said that young people can learn more about the world in a day of huckle-berrying than a year of learning Latin.

One major example of Thoreau’s attention to detail was that many people assumed the pine woods had always been pine woods and the hardwood forests had always been hardwood forests. But Thoreau saw birds in pine trees dropping hardwood seeds onto the ground. Apparently pine woods became hardwood forests, which, when they burned or were cut, reverted to being pine woods. Thoreau may not have been the first to come up with this ecological observation, but he certainly came up with it himself. He even reconstructed the population history of pine woods by counting tree rings.

Thoreau was also a man of scientific faith. That is, he wrote down observations in his voluminous notebooks for which he had no use, but which he thought might be useful to somebody someday. Among his observations were the dates on which various species of wildflowers bloomed in the spring. He was not the first person to keep such records, which we today call phenology; in Japan, some records of cherry blossoms go back for centuries. But Thoreau’s records came in very handy when modern botanists such as Richard Primack and Abe Miller-Rushing compared Thoreau’s data with recent data. The flowers bloom much earlier today than they did in Thoreau’s time, consistent with global warming. Many other scientists, including me, have come up with similar results based on entirely separate sets of plants.

Another thing about Thoreau’s scientific faith. He kept walking because you never know what you might see, and if you are not out walking you might miss it.

And us modern scientists acknowledge the details that Thoreau noticed on his nature walks, even though he did not set out with the intention of noticing them.

The Thinking, Walking Biped, part seven. Famous nature walks: Alexander von Humboldt and John Muir

Alexander von Humboldt was one of the great travelers of world history. He went all over the world, hiking in mountains everywhere. His spirit of exploration inspired generations of scholars after him, including Charles Darwin who took Humboldt’s book with him and followed his footsteps in South America.

But Humboldt did not just travel and hike. He made scientific observations which would later prove fundamental in the study of geography, particularly plant geography. Lots of people have noticed that trees tend to be found higher on mountain slopes, but Humboldt was the one who discovered that trees were higher on the south-facing than on the north-facing slopes. This is evidence that temperature and humidity are the important factors: the trees prefer the cooler temperatures and more humid conditions of the north slopes. After Humboldt’s detailed observations, the patterns of nature started to make sense.

Perhaps most famously, Humboldt ascended the slopes of the Andean volcano Chimborazo, in Ecuador. Because the top is covered by a glacier, and because of the crevasses, Humboldt could not actually reach the top of Chimborazo. When I climbed up the slope of Chimborazo in 1989—likewise not reaching the top—I felt inspired not just by the amazing geography but by the fact that almost two hundred years earlier, Humboldt had stood in that very spot.

 

It is particularly inspiring to stand in the exact location of an historical event. I have had this experience numerous times, including when I walked on part of the Cherokee Trail of Tears, but also on a remnant of the Native American trails near Tulsa, Oklahoma, and also a World War One graveyard in the Vosges Mountains of Alsace, France. I walked to these places.

The image of John Muir is inseparable from the Sierra Nevada Mountains of California. It seems that he walked practically everywhere in the Sierras, and not just during nice weather the way I did in my Sierra explorations. He would not hesitate to climb a tree during a fierce snowstorm and revel in the forces of the wind. He seemed to need only a blanket for shelter and only bread and tea for nourishment.

The Thinking, Walking Biped, part five. Famous Nature Walks: Rousseau Thinking about Himself

Jean-Jacques Rousseau (he called himself J.J.) was a famous writer and thinker of the eighteenth century. His specialty was to pugnaciously disagree with political and religious philosophers. One of his ideas was the social contract. He said that humans were basically good—not passionately good, but inclined to enjoy being good to one another. They did not need political systems (kings, knights, dictators, etc.) or religions (the threat of excommunication and hell) to be good, but just to be given the chance to form a contract of goodness with one another. I realize the full idea is more complex than this, and you are welcome to read more about it.

Rousseau was a great and almost daily walker. It is easy to assume that he used his daily walks to think of new and inspiring ideas about which to write. He stopped in a wooded area after visiting Diderot in prison in 1749. The hike was only three miles, but it is where he had his revelation about the social contract. This was not a wilderness area, but within metropolitan Paris. Still, it was not in a house or library or church, at least. Many writers, including myself, get a lot of ideas while walking. Is this why Rousseau walked?

For the most part the answer is no. His personal views can be kindly described as utter despair, and were most likely paranoia. His daily walks were to forget his past and to be the good man that Nature intended him to be. He described ten walks in his Reveries of a Solitary Walker. None of them were actual walks that he had taken, but were mostly unsorted piles of gripes and complaints. In his First Walk, Rousseau said that nobody could force you to be miserable. He was calm, because, he said, there is nothing more his enemies could do to him. He continued his self-pity in Walk Three, where he said he hoped for little, and received less. But he kept walking, saying that “I need to endure the miseries of my life.” He almost gave up trying to figure out his tribulations; I found myself wishing he had, in fact, given up. He said Solon, the Roman thinker, learned something new every day. But Rousseau said his old brain was worn out and he could not learn anything new. I just hope that as I get older I will never believe this about myself. He believed himself to be the most miserable of humans because literally everyone hated him, except his wife. And so on, with Walks 8, 9, and 10. He had to be a solitary walker, he said, because to understand society he had to stand outside of it. Also, I’m not sure he would have been such a good traveling companion for anyone.

He had some reason to be paranoid. When he lived in Môtiers, France, his house was stoned, breaking his window. The hostility of the local people was probably because he questioned the goodness of religion. During Rousseau’s life, many pamphlets were published against him. Some were apparently written by Voltaire. As Will and Ariel Durant describe it,

In Voltaire and Rousseau we see again the old clash between intellect and instinct. Voltaire believed in reason always; but Rousseau had little faith in reason; he desired action. In spite of his disagreement, Voltaire respected Rousseau’s right to speak what he believed in… Voltaire didn’t agree with Rousseau’s denunciation of civilization. He informs Rousseau that man is by nature a beast of prey, and that civilized society means a chaining of this beast…

But I have not seen evidence (not being an historian, this is not surprising) that people were preparing false and defamatory documents to be inserted into his works to be “discovered” upon his death. Rousseau was not an easy man to like; he could like you and then, as with David Hume and Dénis Diderot, change his mind about you completely.

For most of his life, Rousseau’s walks were nearly blind, as he thought only about himself. He looked at his path only enough to keep from tripping over sticks and stones. But for a brief time, this was not the case. See the next essay.

The Thinking, Walking Biped, part four. Famous Nature Walks: Petrarch and the Great Mt. Ventoux Hoax

I first heard about the Italian poet Petrarch’s famous ascent of Mt. Ventoux in southern France (April 26, 1336) during a high school humanities class. Petrarch supposedly presaged the Renaissance by making this artistic, as opposed to religious, pilgrimage. Some people have called him the first mountain climber because he made his ascent for no reason other than to see the view. An earlier monk (Jean Buridan) had ascended it on his way to see the Pope at Avignon, to make meteorological observations. And other people had probably climbed this mountain for strategic or economic reasons. Petrarch said he met a shepherd on the lower slopes of the mountain who claimed to have been the only person to have climbed the mountain, and he said it was just a bunch of rocks and not worth the effort.

How different it is today. Thousands of people hike, bike, or drive on this mountain. Its steep incline is a famous point on the Tour de France.

Many scholars have concluded that Petrarch did not climb this mountain at all. It was all a hoax.

Here are some reasons for believing Petrarch’s ascent of Ventoux to be a hoax. Petrarch mentions precisely nothing about the natural wonders that he would have seen all around him. Foremost among these is the wind. Ventoux means “windy.” The mistral winds average 90 kilometers an hour for 240 days a year. Mt. Ventoux sticks up into a mass of cold air that moves from the north to the Mediterranean. No mention of it. Also, Mt. Ventoux is famous for its white limestone cap visible from a great distance. No mention of this either. A lot of the bare limestone has resulted from deforestation, which might not have been as extensive in the fourteenth century as today. But most mountains in France have been deforested, and yet few have such visible summits. Certainly there would have been something that Petrarch might have noticed, had he actually been there.

Perhaps most of all, Petrarch made his entire ascent and descent in one day, then went back to the inn and wrote about it before supper. Might we suspect Petrarch, not noted for physical prowess, to have exaggerated his vigor a little bit? Conveniently, he had no eyewitnesses other than his little brother.

Instead of Petrarch being an early Thoreau or Muir, he was actually writing in the tradition of pilgrimage fiction, a tradition that began before Bunyan’s Pilgrim’s Progress and has continued long after C. S. Lewis’s Pilgrim’s Regress. Petrarch wrote about how he kept taking descending trails, hoping to find an easier path, only to have to climb back up and do it the hard way. This, he said, is a symbol of how, when we choose the easier path in life toward spiritual salvation, we have to keep starting over and over again. Bunyan could have done no better.

So if Petrarch is to be remembered today, and taught about in humanities classes, let it least be for something he actually did or wrote, and not for the Mount Ventoux hoax.

The Thinking, Walking Bipded, part three. Jesus

In the past, great religious leaders did a lot of walking. More recently, they have preferred limousines and jets paid for by rich donors who think God wants them to do this. Mahatma Gandhi did a lot of walking. In 1944, a back country preacher named Guy Howard published his biography, Walkin’ Preacher of the Ozarks.

Jesus of Nazareth walked everywhere during his short ministry on Earth. He gave the impression of wandering aimlessly—at least, he did not explain his itinerary to his disciples. He wandered in the desert, and took his disciples north into Galilee, the country-bumpkin part of Israel where he was born. He briefly rode on a donkey, when he triumphally entered Jerusalem on his last Passover.

Can you imagine how different Jesus’ impact would have been on his listeners, and on history, if he had ridden around on a horse and preached down at the people, with his sword sticking out?

He certainly gave the impression of poor planning in his walks. He did not arrange for his disciples to have enough food for them to eat, and wouldn’t you know it, he was leading them right through Samaria. Samaria was the place with the remnants of the northern kingdom who worshipped in a way Jerusalem Jews considered unholy. Righteous Jews did not want to even be in Samaria, much less get caught there without food. The disciples went off to find food, leaving Jesus alone at a well.

We see now that Jesus had planned it this way all along. A woman came to the well to draw water. She noticed Jesus did not have a bucket and wondered if he would like a drink. He offered her living water, which confused her. He surprised her by telling her about her past: she had had a succession of lovers. It couldn’t get much worse for a righteous Jew—having a personal conversation with a Samaritan woman of loose morals. The disciples were not pleased. Long afterwards, Christians realized that Jesus was teaching them, and the Samaritans, something important about how God does not look down on certain cultures of people.

Jesus summarized his whole way of life as not just walking, but walking on narrow, difficult paths. It is on such paths that you learn about the world and about yourself. Can I, in fact, complete this path, and more, can I learn from it and enjoy it? “Enter in at the narrow gate,” he said. “For the way is narrow and the path difficult that leads to life, but the way to hell is smooth and wide.” I preached a sermon on this topic to a bunch of Boy Scouts about 1969, when I was a scout myself. We were camping and hiking in the lower Sierra Nevada mountains.

As a botanist who walks nearly every day, I can tell you that the easy roads are mostly bordered by weeds; to find the beautiful wildflowers, you need to hike the narrow trails.

 

The Thinking, Walking Biped, part three. Epic Journeys

A lot of the celebrated epic journeys in human history have been on foot. The alpine ice man Ötzi was beginning such a journey when he was shot in the back with an arrow five thousand years ago. These journeys show up in literature and movies a lot. One recent example is the movie Revenant with Leonardo di Caprio.

I will tell you about one such journey you’ve probably never heard about, from the 1959 French movie La Vache et le Prisonnier (the cow and the prisoner). We think of Nazis as keeping prisoners in special camps, such as the one in The Great Escape. But there were so many prisoners of war that the Nazis had to literally “farm out” their prisoners to farms and ranches in the countryside. German farmers, rather than soldiers, kept the prisoners from escaping, which they could not do anyway since their only garments marked them as prisoners. This was the same thing that the American army did with German prisoners in sending them to agricultural work camps in California. I grew up across the street from the ruins of one such work camp in Lindsay, California.

One prisoner in the movie had a brilliant plan. He took a cow from the farm where he was interned, got a map, and decided to walk back to his home in France. The German farmers who watched him did not care very much if he escaped. The only enthusiastic Nazis were the officers. But the prisoner had an excuse: he said he was taking the cow from the farm where he was imprisoned to another farm; that is, it was part of his work to take the cow someplace else. He had one humorous mishap after another until he finally got on the train to Strasbourg. The movie was famous enough in France that many cows were named Marguerite in honor of the cow that helped the man escape.

Many epic journeys are on foot. I tell about more of them later. The more on foot, the more epic the journey.

The Thinking, Walking Biped, part one. Pascal Picq and Human Evolution

This essay begins a series about the importance of walking in human evolution and history.

Cogito, ergo sum, said Pascal, or someone. I think, therefore I am. In French it would be je pense, donc je suis. But one French writer, an anthropologist named Pascal Picq, has changed this a little. He says, je marche, donc je pense. I walk, therefore I think. He has made the case that we are not just bipeds who think, but we think because we are bipeds. He attributes the evolution of human intelligence not just to the fact we are bipeds, but because we are bipeds who can walk and run for long distances, with outstanding endurance not found in other mammal species. Maybe this is obvious to you, but I’d never thought of it until I read Picq’s book La Marche.

Picq overviewed the history of scientific explanations for why humans walk upright. This has always been somewhat of an enigma. Quadrupeds can run a lot faster than we can. Anthropologists have come up with all kinds of advantages that bipedalism conferred on our ancestors, such as being able to look out over the vegetation to see either danger or opportunity, or to use our forelegs as arms that can carry things such as food and kids and weapons. Long distance migration is what evolution has favored in our species: even old people can walk long distances unless they have health problems or are injured (I do it nearly every day), and there are a lot more elderly marathon runners than elderly speed sprinters.

While these things are all true, Picq has added another: bipedalism has altered the evolution of our minds. Bipedalism (as in Australopithecus) preceded intelligence (as in Homo), and here are some reasons why.

Humans are superb wanderers and have been so throughout our evolutionary history. National Geographic writer Paul Salopek is retracing, on foot, the epic journey of humankind from our African genesis to the end of the journey in South America. Other mammals run faster, but do not migrate as far as humans have. Starting about a hundred thousand years ago, prehistoric humans spread from Africa to every continent except Antarctica. These migrations set up an advantage for intelligence, because our ancestors had to decide whether to migrate (that is, is migration worth the cost of leaving home), and then how to get someplace and know that the new place was where we wanted to stay. This required superb observation and memory of the environment and ability to analyze opportunities. This was true on the short scale (we want to go this way, but there is a river, and we have to figure out how to cross it, which may involve turning around and going back the way we came) and the long scale (we want to get to that hill, from which we can see into the distance and plan what to do next, if anything). Homo sapiens was apparently better than this than Homo neanderthalensis. Our intelligent ancestors also had to think ahead about, and remember, the migration routes and habits of their prey. Neanderthals killed mastodons; humans planned ahead about where the mastodons would be before trying to kill them.

In all these ways, our thinking evolved as a series of logical steps. That is, it required reasoning ability. A primitive (or modern) philosopher or scientist will try out ideas to see if they work, then come up with a backup plan if it doesn’t. This, Picq speculates, uses a similar mental network to figuring out where to go and how to get there on foot.

On top of all that, walking and running makes us feel good and releases us from stress. Picq said he got some of his best ideas while walking. I have the same experience. And perhaps the best example is Charles Darwin, whose “walking path” at Down House was where he got, and perfected, his major ideas. He did not get them sitting at his desk. Many famous composers, as well as other scholars, carried writing equipment with them. I have heard that Beethoven and Dvořák wrote musical ideas as they walked (see a later essay on this topic). Today, we have cell phones on which the thinking walker can record ideas.

According to Picq, what science and philosophy needs more of is people who walk and think, rather than sit at desks and read what other people have written.

Springtime Secrets (Something to Do During the Pandemic)

I am posting this from the midst of the coronavirus pandemic in America. Many of us are down two only two major activities: working online, and taking walks. Like most universities and colleges, the one where I work is closed the rest of the spring semester, and students will complete their classes online. My wife and I take walks out away from other people, and watch all the wonders of nature, even when it is despoiled by human activity. This is what we have always done, but for some people, taking a nature walk might be a new activity. If you are one of those people, let me tell you some of the things you might notice.

Spring has been underway for some time in Oklahoma, where I live and work. But it has only recently been making itself obvious. Spring comes, but not all at once. The first thing to notice as you take your walk is that not all the trees open their buds at the same time. The elms opened their buds over a month ago, and they are now fully displaying their green seeds. Whole forests of elms are blushing a light green right now. This color is due to seeds, not leaves, which are only now beginning to emerge from their own buds.

Meanwhile, other tree species appear to still be dormant. In the photo below, the elms are green but the Kentucky coffee-tree (identifiable by its big seed pods) is still dormant.

Notice, then, that each kind of tree follows its own spring schedule.

The trees also display diversity within each species. The photo below shows two cottonwood trees. One is in full bloom (on the right, with clusters of little reddish flowers), the other is not. In this case, the tree in full bloom is a male tree, while the other one is female. Its greenish flowers will open up a little bit later. Just as male birds migrate before female birds, the male cottonwoods open their buds before the female cottonwoods. In trees, as in animals, the males compete with one another for access to the females even when, as in cottonwoods, it is completely without intelligence.

This is also the time of year that birds begin their social activities. In Oklahoma, mockingbirds and cardinals are already singing.

The final thing to notice is the garbage. Before the leaves open and the grass grows, thousands of pieces of garbage are visible all around the “natural” areas of Tulsa. (We have counted some of them; I do not exaggerate.) March is the best time of the year to see one of the ugly impacts that humans have upon the natural world.

Take a walk. It doesn’t cost anything, and it doesn’t expose you to viruses. You don’t need to download a movie. The natural world around you has plenty to see.

Walking—A Connection to Our Evolutionary Past

Our bodies evolved to enable prolonged exercise, which is quite absent from our modern lifestyle. We have used technology to create artificial environments, but not environments to which our bodies are adapted. My preferred form of exercise (one which, unlike organized sports, is consistent with my general clumsiness) is walking.

Walking uses up blood glucose, and it does so happily: you can relax, you can notice things about trees and birds and people, and it doesn’t cost anything, except for some cheap shoes. And it is something that most people (including most diabetics) can do. There is no minimum amount of walking less than which is useless. And it brings lots of oxygen into your alveoli. Once in a while I even break into a jog, though not for very far.

Of course, unexpected problems can arise. For me, it is the fact that in rural Oklahoma, nearly everyone drives a pickup truck that belches out huge billows of fumes. Even the new ones. I wonder if part of the standard detailing of new trucks in rural Oklahoma is to attach a little spigot that sprays fumes into the air directly from the fuel tank. (I just made that up. That doesn’t mean it isn’t true.) Almost every man in rural Oklahoma is so worried about his manhood that he feels he has to compensate for whatever he has to compensate for by getting a big truck (sometimes with truck balls). (I didn’t make that part up.) And of course they leave a stream of fumes that the wind blows into my alveoli for an entire block. If there is one truck on the road, it will find me and pickle me in its hydrocarbons. And of course almost everybody lets their dogs run loose. The dogs would probably eat me if I were not glazed with petroleum derivatives.

Walking creates a positive feedback loop. The more walking, the more capacity for walking.

Walking allows me to notice things about trees. What I did not expect was that my observations would become useful. In 2006, I started making maps of the trees along my walking route, and writing down the day in spring when each tree burst its buds. It turns out that, from 2008 to the present, the trees have been opening their buds about two days earlier each year, a rather striking record of global warming. A research presentation at the world meeting of scientists who study phenology came out of these observations.

By pursuing a healthy lifestyle, I make myself a better participant in the health of the planet, create a positive feedback loop for even greater health, and open myself up to serendipity.