Sunday, May 28, 2017

The God Molecule

I am a convinced evolutionist. Having worked in a biotech firm that made genetic analysis equipment and reagents, and so having learned a bit about biology, I can see the relationships among all life on this planet through our shared inheritance of the DNA-RNA-protein coding system. Everything on this planet that we think of as being alive—from bacteria to bats to banyan trees—uses this system. And every species, genus, family, order, class, and on upward through the traditional biological classifications attributed to Carl Linnaeus in the 18th century can be measured and compared by the number of shared genes and genetic mutations the representative organisms possess within this coding system.1

It’s not that every organism has a “DNA-like” system, allowing for some mechanical or chemical variations. No, they all—from slime molds to sea urchins to sparrows—use the same DNA system, intact and whole. That system has four bases—adenosine (A), cytosine (C), guanine (G), and thymine (T)—which are always paired A to T and C to G. It arranges these four bases, which are variously purines or pyrimidines, in a three-base “reading frame” yielding sixty-four possible code combinations, called “codons.” It uses these combinations to call up just twenty amino acids from among the 200 or more amino acids that exist in nature.2

There are minor variations within the system itself. For example, DNA differs from RNA in that the second carbon atom in the sugar ring of each base has an attached hydrogen atom (H) rather than the hydroxyl group (OH) found in RNA—and thus DNA is the “deoxy” ribose nucleic acid. And the RNA strand itself substitutes the base uracil (U) for thymine (T) in transcribing the coding sequence. But those are about the only differences—and they are used in all branches of life.

All organisms use the same DNA start codon ATG—the only codon calling for just one amino acid, methionine—as the beginning of any protein-coding gene and as the start of the messenger RNA strand (where it’s written AUG) that will translate the gene into a protein. So all protein strings start with methionine. And all organisms use one of the three DNA stop codons TAG, TAA, or TGA (in RNA as UAG, UAA, or UGA)—and none of these sequences codes for any amino acid—to end the gene and its corresponding messenger RNA strand.

Nowhere on Earth do we find organisms that use a different coding system; or use different bases from among the eight possible purines and pyrimidines found in nature; or employ a four- or five-base reading frame for more possible combinations, or a two-base frame for more compact and efficient coding; or call on a different set of amino acids to create new and exotic proteins. Some of the mechanisms that support the system are different. For example, single-celled prokaryotes, which have their DNA scattered throughout the cell body (rather than contained within a nucleus, like the multi-celled eukaryotes), use a different ribosome to translate the messenger RNA strand into a protein string. This is one of the reasons you can take an antibiotic to kill the bacteria in your body without harming your own cells: the medicine attacks the bacteria’s protein coding mechanism, and yours is different from that of the bug that’s infecting you.

As a mechanism for evolution, the DNA-RNA-protein coding system is superb. The DNA molecule is fragile, susceptible to environmental abuse through radiation and chemical assaults. But the system itself, with sixty-four bases calling twenty amino acids, has a lot of redundancy. You can change or knock out the third base in the reading frame’s codon—sometimes even the second base—and you still have a good chance of calling the appropriate amino acid.3 And large complex proteins often have parts of their molecular structure that can be modified or removed without changing their essential function. If some smart person were trying to design a chemical system that allowed for environmental change, but not too much and not too fast, the DNA molecule would be it.

And one of the great biological and geological understandings of the past hundred years or so is that the Earth’s environment is constantly changing, and that species must continuously change with it or else they would die out quickly. Our Sun goes through millennial and epochal cycles of warming and cooling, the continents drift over the ages on tectonic plates, mountains rise and erode away, streams meander and shift, lakes form and evaporate. An animal or plant species that could not change its form or function in some degree, large or small, over the generations would not survive in this changing landscape.

So the old Platonic idea, preserved in Genesis, is pure intellectual fantasy. Plato held that, while horses in the field may come in many varieties, different sizes and colors, shapes and strengths, there exists somewhere an ideal form—the Horse, perfected in the mind of God. This gives rise to the notion that a species, like Equus ferus caballus or Homo sapiens has some mystical, “pure” essence. But each variety of horse, as well as those of zebras and donkeys, were all adapted through a haphazard blending of mutational changes to fit its particular niche in an environment that was basically solid, level ground suitable for running over and covered with grass that was good to eat. If it had benefited the horse family to have toes like wolves or lions—or like their ancestor, the multi-toed Eohippus—instead of hooves, then we would now have horses with toes. If an early horse family and its line of ancestors going back millions of generations to some Theropoda dinosaur had evolved the metabolism to fill a niche that profited from eating grubs and worms, then we might now have horses with beaks.

But there’s paradox in all this. While the DNA-RNA-protein coding system is admirably suited to evolve the organism it creates and fit that species into its current environment, the system itself shows no hint of its own evolution.4 Again, the supporting mechanisms may have evolved, like the various forms of ribosomes. For example, the single-cell prokaryotes have DNA chromosomes that are looped in a double-stranded structure, called a “plasmid,” that floats inside their cell bodies, while the multi-cell eukaryotes have chromosomes that are tightly coiled, wrapped around knobs of protein called histones, and segregated inside the cell’s nucleus. In either case—from Salmonella typhi to salmon—it’s the same DNA, transcribing its code onto messenger RNA, which some form of ribosome then translates into a protein.

It is possible that the Earth originally spawned multiple coding systems. DNA-RNA-protein might have been in competition with other molecular forms and chemistries.5 For example, within the domain of our current carbon-based organic chemistry, early life forms might have employed more bases, larger reading frames, and more amino acids from which to choose. The evolutionary development of something as fundamental as a molecular coding system would have taken place so early in the start of life on this planet that other competing forms might have died off before the crust quite cooled. And these complex chemistries, without the skins, shells, and scales of organic bodies to protect them, would have vanished without a trace in the turbulent environment of early Earth. But surely somewhere, hidden among the lichens and fungi, the bacteria and the molds, shouldn’t we have found an example of some poor, under-developed organism that preserved at least one of these alternate coding systems? No, nowhere. Not in the strange tube worms and sea spiders clinging to a volcanic vent in the deep ocean a hundred miles from their nearest organic neighbors. Not in Antarctic lakes buried under miles of ice for millions of years. The entire living world is created from the same DNA-RNA-protein coding system that gives us mangos, manatees, and human beings.

Which raises the tantalizing prospect that this coding system did not evolve here in the first place. Maybe it was seeded when a carbon-based astronaut from a distant star, who was visiting Earth soon after the crust hardened and the oceans formed, dropped a glove with a bit of his/her/its cellular chemistry attached. Maybe a spore of some alien bacteria blew into the solar system on a grain of dust from some other star system.

And there are people who can accept that organisms may evolve through changes in their DNA but who doubt that the basic chemistry—those ribose rings and phosphate bonds, the structures of purines and pyrimidines, and all the rest—could have come together in the first place to record molecular traces. Not here, and maybe not anywhere in the universe. And even if those first long-chain molecules could arise here or elsewhere, why would they? What would they be preserving for posterity, other than their own coding? And then, why would they put together A and T, C and G, in preference to any other combination? For, after all, molecules at that level might form spontaneously, but they wouldn’t create anything. Eventually, they would break apart under the stress of some other chemical reaction. Bare molecules have no reason to preserve one sequence as more successful in their environment than any other.

Although I am not a deist and have no belief in a supreme being, it is possible that the DNA-RNA-protein coding system was designed for the purpose that it so admirably fulfills. DNA and RNA are not even that hard to make. At the biotech company, we had factory that manufactured the ribose rings with their attached bases and their phosphate-bonding tails. We synthesized long chains of single-stranded DNA as primers designed to anneal to the sequences in wild DNA, copy them, and then reproduce to amplify them, in the process known as “polymerase chain reaction.” This is the basis of most techniques of genetic analysis and sequencing. We now know how to knit those synthetic strands of DNA into artificial chromosomes, wrap them in a coat of proteins and lipids similar to a cell membrane, give them a basic metabolism, and nurture them in the laboratory as a primitive cell.6

If human beings can master—or at least start using—this technology a mere sixty years after we first defined the DNA molecule, then a more advanced civilization on a planet around one of the billion stars in the Milky Way, or in one of the trillion other galaxies in our universe, might have become very good at this kind of synthetic creation. Perhaps this forefather civilization was carbon- and DNA-based itself, and they metaphorically plucked a rib from their side and turned it into the seeds that became all life on Earth and perhaps on other planets, here and around other stars. In that case, they might know the secret of how the first DNA coding system itself evolved. Or perhaps these scientists or missionaries—or gods—evolved in some other form and merely thought up the DNA-RNA-protein coding system as a good way for creating that temporary reversal of entropy we call life.

And maybe—I’m just freewheeling here—there really is a Supreme Being, an All Soul, a Divine Spark, Which/Who touched the Earth’s chemistry with its all-seeing inspiration and foreknowledge, and thereby designed a molecular system that would transform a barren planet into one teeming with chemical energy, adaptability, and eventually with thought itself.

1. See also DNA is Everywhere from September 5, 2010.

2. Two additional amino acids in common use are added to some proteins by enzymatic action after the messenger RNA sequence has been translated into the polypeptide chain.

3. See, for example, this chart of the genetic code from a biology course at Kenyon College.

4. Well, one hint. The RNA molecule is always single stranded, and that OH group on the second carbon in each base keeps the long-chain molecule from coiling around itself. DNA is always double stranded, and that missing oxygen lets it form the iconic helix shape. So the RNA form is simpler, straighter, more exposed to chemical damage, and perhaps more primitive. This suggests to some biologists that, as a record-keeping molecular system, RNA may have come first and then DNA, with its tighter, more complex, more robust structure, may have evolved from RNA. But we find no living organisms that use only RNA not in combination with DNA. However, some viruses, called “retroviruses,” have RNA-only coding and use a reverse transcriptase to make DNA copies of their code once they invade a host cell.

5. For example, it’s possible to imagine a silicon-based life form, with silicon taking the place of carbon in its DNA-surrogate’s ribose rings, purines, and pyrimidines, and with arsenic taking the place of phosphorus in the phosphate bonds that provide cellular energy and knit together those ribose rings into the DNA structure. Such a system would have heavier molecules, because the component atoms have a higher atomic weight, and the molecular bonds would be weaker, because the electrons holding the atoms together would be traded among shells farther out from their atomic nuclei. However, such heavy, fragile molecules would be at a disadvantage in competition with a lighter, stronger DNA molecule.

6. See, for example, “ ‘Minimal’ cell raises stakes in race to harness synthetic life” in Nature News, March 16, 2014.

Sunday, May 21, 2017

History a Thousand Years from Now

If historians from the 30th century, the far future, look back on our time, what will they see? What will they know and understand about our period?

First, let’s assume that they have full access to our writings and recordings, but they are not personally subject to our current states of thinking and feeling. That is, future historians might be like a modern audience seeing Romeo and Juliet with the original Shakespearean dialogue. They might hear the words as actors of the late 16th century spoke them, and they might have some sense of their meaning. But a modern audience might not fully understand what social forces drive two powerful families like the Montagues and Capulets to gather their extended kin into rival armies and fight in the streets of medieval Verona. And if they did understand those forces, they still might not feel the hatred in their own breasts. For us moderns, the rage of Tybalt and the wit of Mercutio remain distant curiosities.1

However, even an Elizabethan audience might not have been able to say what exact qualities of mind or habit made the Montagues so loathsome to the Capulets and vice versa. The evidence supporting the feud between these “two households, both alike in dignity” does not exist in the play. Instead, it’s an “ancient grudge”—which is Shakespeare’s version of the MacGuffin that sets his plot in motion.

In similar fashion, what would far-future historians know about the passions that seem to be tearing the United States apart and ravaging many of the other Western democracies as well?

On one side, they might see a radical strain of progressivism or passionate futurism. This is expressed in a number of different popular movements—inspired by the writings of various political philosophers like Marx, Lenin, and Mao—but with the same aim of overturning the adherents’ existing society and its political, economic, and social structures. The radical’s goal is to create a new state, a new basis for economic transactions, a new morality, and a new set of relationships between men and women, between parents and children, and between citizens and the state. This new order is always projected from rational, egalitarian, humanitarian, compassionate, and collectivist principles. It is based on theories about human nature and visions of a future that has never before been experienced on a countywide scale.2 And the fact that every country which has attempted to enact these theories and visions thereby sank itself into chaos, political repression, and self-inflicted poverty is dismissed as a failure, not of the theories and visions themselves, but of the imperfect people making the attempt.

On the other side, the future historians would see a passive strain of conservativism or traditionalism.3 This side of the argument has no popular movements and only weak political associations. This side has no coherent philosophy based on novel thinking but is reflected in writers like Edmund Burke, David Hume, and Adam Smith, who—rather than creating a vision of a new social and economic order—were trying to understand and express how people actually go about their political and economic business in developed societies. The adherents’ goal is not so much to build anything new as to preserve and defend those structures and relationships that have grown up in their own society over the decades and centuries. They don’t mind certain people obtaining and wielding political power and economic advantage, but they haven’t subscribed to the new theories and visions. They don’t mind their society evolving, moving slowly toward different values and accepting different relationships through a kind of unspoken plebiscite. But they resist the notion that a cohesive and doctrinaire group, fired with strong ideas and emotions, should push their society into configurations that are either untested or have been found in the past to be disastrous.

The historians might trace out the sequential steps—the published positions, the party platforms, and the pivotal elections—in this growing social disruption. They might assign causes to the society’s failure to adhere to its former constitutional structures and its market principles, as well as its failure to provide adequate rewards for effort and risk taking. They might read about demands for personal compassion and complete equality among all members of society. They might hear the siren call of an enlightened utopia … but they will not be able to feel its pull. They will remain deaf to the dimension of imagination that drives the collectivist movement. And without an exercise of imagination and empathy, they will not know the depth of revulsion among those others who can accept social evolution but not political revolution.

What the historians will see in our times is a social madness based on masochism and fear. They will see people in the most advanced societies the world has ever known struggling with a loss of existential faith. People on one side insist their lives are impoverished among an outpouring of goods and services. People on the other insist their lives are threatened simply by words and ideas. People on both sides are convinced the other has no understanding of—or respect for—them and their cause. Modern Montagues and Capulets bite their thumbs and spit on each other’s shadows without a clear remembrance of the ancient grudge that separates them.

Modern Americans look back on the political and social tensions of the 19th century that led to the first Civil War, and they grope for an explanation. “It’s all about slavery.” “It’s all about our way of life.” “It’s all about human rights.” “It’s all about my rights.” We look for simple, easy explanations of a complicated past that ended in five years of bitter war and the loss of more than American 600,000 lives.

If the divisions tearing at our society right now result in a second Civil War, what will future historians say? Granted, that first conflict was regional, based on two societies, North and South, which had grown apart—or had never actually been much alike—with their differing social values and economic systems, although with a single constitutional basis.4 The next conflict will be intellectual and visceral, with enclaves of sentiment and purpose concentrated along the country’s two coasts and among its urban elites, but otherwise with neighbor opposing neighbor across the width of a backyard fence. The next war is going to look more like a street fight or a riot—Montague and Capulet style—than any conflict between settled countries.

Will anyone in the far future understand it better than anyone alive today?

1. For a different sense of this family antagonism, here is Prokofiev’s “Montagues and Capulets” from the Romeo and Juliet ballet. It’s one of my favorite pieces.

2. But see When Socialism Works from October 10, 2010.

3. The word of the moment is “populism.” Supposedly, this reflects an aversion by the average person and the populace as a whole from the theories and visions espoused by a radical elite of political, academic, and cultural thinkers and leaders. A decade and more ago, it was the “people,” the populace itself, who were supposed to align with these theories and visions against the repressive forces found in traditional society. See how the language changes?

4. In fact, the Constitution of the Confederate States of America was practically a word-for-word duplicate of the U.S. Constitution, with some significant differences particular to the Confederate cause. Clearly, the foundation and structure of the government were not in serious contention.

Sunday, May 14, 2017

Wolves and Dogs

By now it is generally accepted, although not entirely proven, that dogs evolved from wolves.

The best current theory is that, rather than humans stealing wolf pups and feeding and raising them at their campfires, some subset of wolves domesticated themselves. In this theory, the hunting pack was supposedly attracted to the edible scraps found in the humans’ kitchen middens—waste piles where hunter-gatherer groups tossed their old bones, discarded skins, and other refuse. Because the humans came randomly and often to dispose of these wastes, the wolves could not avoid contact with this large, strange, and unpredictable species. Over time, the wolves which demonstrated the most tolerance of human presence got the best and the freshest scraps. Fearful or hostile wolves kept their distance and got less of the good stuff.

This theory dovetails nicely with the work of Russian biologist Dimitri Belyaev, who bred foxes for tameness. Working sixty years ago, this dissident from Soviet biology began studying foxes in order to disprove Lysenkoism—the Lamarckian theories of Trofim Lysenko, who said traits acquired in life could be passed along to later generations. Stalin loved Lysenko’s ideas, because they proved that the Soviet state could, with sufficient force and enough reeducation camps, create a new “Soviet man,” whose selfless passivity and obedience to the Party would breed true and ensure Communist dominance into the future. Belyaev’s foxes—animals of the same family, Canidae, as dogs but not the same genus—gradually changed their physical appearance as well as their behavior. Through hormonal mutations associated with their tolerance of humans, the foxes over generations developed shorter snouts, rounder heads, and changes in coloring—among the same set of features that differentiates dogs from wolves.

How is this not evidence of Lysenkoism? Because in both cases—the wolves at the kitchen middens, Belyaev with his caged foxes—the changes depended on selective breeding for certain qualities. Both cases depended on various traits—fearfulness and hostility, or their lack, along with the associated neurochemical and hormonal differences—existing in the animal at birth. In the beginning of each transformation, these traits existed as random genetic mutations; in later generations, they were selected and reinforced through breeding. Wolves that could tolerate the human presence ate better and were more successful in mating; wolves that feared or avoided human contact either died out or returned to the forest. Belyaev’s fox pups that could tolerate being handled and liked being played with were allowed to breed at maturity; pups that snarled and snapped like wild animals were discarded from the experiment. Whether the selection is a natural circumstance of the environment around the midden or an intentional choice by a human breeder, the result was the same. A gradient of selection—a test for survival traits—was imposed on the breeding group, and the preferred traits were passed along to succeeding generations.

Every farmer does this, and it’s been going on since human beings first stopped roaming after the wild herds and settled on the land. We find a type of berry we like, plant it separately, control its pollination, and turn it into a brilliant red tomato—or a coffee bean with a particular flavor, or a luscious strawberry, or a conscious hybrid like the loganberry. We find a type of grass whose seeds are palatable and turn it into wheat—or corn, or any other type of grain. We find boars with the tenderest meats or wild horses with the strongest backs and turn them into farm animals. And dog breeders, like my aunt, find poodles with the best combination of form, disposition, and coloring and breed them to create a line of miniature and toy dogs that are exact replicas of their larger cousins. Other breeders find dogs that are attentive to human desires as well as quick and clever with sheep and turn them into herders and healers. We’ve been doing this for ten thousand years.

In most cases the original specimen remains, for the rest of us, obscure. The original and unattended tomato plant has either died out for lack of habitat or hides in a forest glade somewhere, unrecognizable to passing hikers. The original boar might lurk in the forest and become the target of occasional hunting parties, but for the most part the production of pork for barbecue ribs and savory sausages remains hidden from the average customer’s attention.1 Wild horses still exist in the American southwest, but they are only the feral descendants of domestic horses brought to this continent by Spanish explorers. The original, prototypical horse—Przewalski’s wild horse of the Central Asian steppes—had once almost gone extinct and has since been preserved only as a curiosity.

In these cases, the average person has no emotional attachments, either to the farmed pig or the feral boar. But in the case of wolves and dogs we have both attachments and opinions.

Wolves exist in the public imagination as noble creatures. They are bound to the pack, loyal to their mates, fierce in their hunting, sleek in appearance, and bold in their status as predators. Although wolves might be the subject of childish fears born out of fairytales and horror novels, for most people they the emblem of everything that is implacably wild and free—and true to itself. The wolf has its own nature.2

Dogs exist in our homes as loving companions. They are biddable, fawning, loyal to our family, suspicious of strangers, and gentle with our children. Many people sleep in the same bed with their dogs. The average dog, with its rounded head, floppy ears, and wagging tail, is now more our court jester and emotional pillow than our guardian and defender. Yes, a large dog can be trained to become fierce and unfriendly, but they do so only in response to human bidding. Their nature is to trust and depend. The dog has the character we give it.

For many people, the transformation from wolf to dog is a travesty, if not a tragedy. We—or our table scraps—have created something unnatural, in defiance of nature. We have taken an animal that was once self-sufficient and uncompromising and turned it into a beggar and a clown. But the wolf of our imagination would make a poor playmate for our children, have no interest in defending our homes, and would not sleep in our beds or even doze in our strange and dangerous presence.

For others, the wolf in the wild is a menace to livestock, a danger to house pets and babies, and at the very least an unpredictable presence around ranches and farms. There are still people who will shoot a wolf on sight, even while environmentalists are trying to restock and encourage them in habitats where they once roamed. The wolf is a topline predator in an environment that offers ever fewer prey animals and so has become a nuisance.

None of these considerations, of course, is of any concern to either the wolf or the dog. It is performing in its environment and reacting to stimuli exactly as its genes were selected to do. It is fitted for survival under the circumstances in which it finds itself. And this is perfectly natural.

Wolves and dogs are both still fresh in the human consciousness and imagination. They are a reminder that our species has changed the natural world in ways that we believe are both good and bad. We bend species to our will. We change forest and field into plantation and farmland. We occupy so much of the land and use so much of the rivers flowing across it that, in many areas, “nature” is a thing that must be preserved behind a fence.3

Which is preferable—wolf or dog? That depends, like so much else, on your viewpoint and your purpose. I for one am glad that the distinction exists. I am proud that we have had a hand in engineering a companion who can remind us to be kind to creatures that are different from and less capable than ourselves. And I am pleased that we can still value the wolves of our imagination while petting the dog that stands at our side.

1. The visceral distinction between husbanded animals in production on the farm and their prepared flesh on the customer’s fork is linguistically preserved in English as a relic of the Norman Conquest. The words “pig” and “cow,” from Middle English, are retained for livestock, while the words “pork” and “beef,” from Old French, are kept for meats in the kitchen and on the table. This verbal distinction came about when the Anglo-Saxon field hand still worked to raise the food for his Norman overlord.

2. We have friends who once had a pet dog that had been bred from a line intended for pulling sleds in races like the Iditarod. Its genetic mix was part Siberian, part husky, and part wolf—the latter added for endurance in long races. This particular animal was devoted and loyal to its humans, but it did maintain a certain aloofness and dignity which the owners attributed to its wolf nature. For example, the dog would enjoy cuddling and being petted but would not allow you to touch it with your feet. The animal seemed to sense that feet were different from hands and represented an indignity.

3. However, the people who think we’re “destroying the planet” need to get out of their apartments in Berkeley. Great tracts on this continent—and on most of the others—still manage themselves pretty well under natural conditions. Humans, for the most part, live clustered along the coasts and in the river valleys. We are still thin on the ground over much of the Earth.

Sunday, May 7, 2017

On Safety Measures

Human nature seems to have a built-in equilibrium system. We are very good at evaluating situations and systems and then invoking a sort of psychological compensator.

Take, for example, the latest models of full-featured cars. They all come with advanced safety options like lane-departure warnings, backup cameras, adaptive cruise control—which adjusts its speed to that of the car ahead and even stops—and other technology that helps the human driver guide and control the car. These vehicles are halfway between the old-fashioned automobile with just human hand-and-foot controls and a clear glass windshield, and the prototype self-driving cars that can follow the road and make complex decisions without human assistance.1

I predict that, rather than make us all safer, these devices—especially lane departure and collision avoidance—will make the person behind the steering wheel less attentive to driving. Many drivers will now think that it’s okay to text or chat on the phone, even with strict laws against these practices, because the car will warn them if anything really important is happening. That’s the psychological compensator in action.

Of course, people still text and chat without any such assistance. When I was doing the long commute down to the biotech company each day, for a while I rode in the company-sponsored vanpool. Sitting high above traffic, we could look down into the cockpit of the cars moving alongside the van. I would routinely see a woman applying eye makeup using the rearview mirror, a man shaving, or someone reading a book propped against the steering wheel. The trouble was, they were all doing sixty miles an hour in dense traffic. But because the road was fairly straight and all the cars around them seemed to be holding their position, these drivers thought it was safe to keep just part of their attention—the eye not getting the makeup, or an occasional glance at the road every other sentence—on the business of driving. With automatic helpers like side cameras and front-mounted radar, these drivers will spend even more of their time on personal business.

In the same way, I’m pretty sure that people who have robotic vacuum cleaners—those flat disk-things that prowl around the room sweeping up crumbs and pet hair—are less conscious about picking up after themselves. And now that every processed food is designed for the microwave, and people are already less conscientious about preparing their own meals, many are careless about reading and following the instructions on the box or can. Just put it in and “nuke it” for a minute and thirty seconds on full power. See how that turns out and repeat as necessary.

People are not necessarily scofflaws or careless. They just have an evolved sense of how to read a situation and judge their own safety and efficiency. Sometimes this sense is faulty—as we can see from those humorous “fail” video clips on Facebook, showing young men attempting parkour jumps from a second-story roof onto a dumpster, or riding a motorcycle at speed up a plank into the bed of a pickup truck. But for the most part people look at their life situation with some precision, and they weigh their expenditures of attention, energy, and time against what they see.

For example, we live in a high-rise condominium with a three-level garage that has one entry point at the top of the structure—the garage is built into a hillside—and an exit on each of the lower floors. Everyone parking there must go some distance around the garage to get to their stall, and many people with stalls on the bottom floor must make two full circuits. Crosswalks are well marked but sometimes blind, and each of walkway is protected with a stop sign for oncoming vehicles. Still, most people travel through the garage at about fifteen to twenty miles an hour. Given the available sight lines, that feels like a safe speed. Some people travel thirty miles an hour or more, and that’s just too fast if others are backing out of or walking away from their stalls. And yet the condo association has rules limiting the garage speed to five miles per hour and has posted this limit on every other pillar in the structure.

Five miles per hour is just a fraction above human walking speed. Given the distances involved, that means most people will take ten to twenty minutes to drive from the entrance to their stall, or from their stall to an exit.2 Most people don’t factor that kind of delay into any of the trips for which they want to use their car: starting on the morning commute, getting back in the evening, of just dashing over to the shopping center. Nobody in our garage drives five miles an hour. They don’t have to, because their internal sensor says that three to four times that speed is still safe. There’s no cop around to ticket them—just occasional newsletter blasts from the homeowners association reminding us of the speed limit. And yet, at those higher speeds, massive carnage does not take place.

In the broader society, we have town councils, state lawmakers,3 and federal legislators passing all kinds of rules and regulations designed to make people safer. For example, the State of California posts sixty-five miles per hour as the freeway speed in most areas, only going up to seventy on certain long-distance freeways out in the countryside, like Interstate 5, where the sight lines stretch for miles. I can tell you from experience that if you’re not doing seventy-five or eighty on the road, you’ll get run over. And I have had Highway Patrol cruisers careen past me—sans lights, sirens, or any other sign of authority in a hurry—as if I was blocking their lane. When all the fish in the stream are breaking the speed limit by ten to fifteen miles an hour, I guess you save your tickets for the ones doing ninety or a hundred and weaving in and out of lanes.

The city might put a stop sign at every corner and a traffic light every other block, and people would still roll through if they could see that nothing’s coming at them for a quarter-mile. More safety measures, especially those that fly in the face of a human being’s internal evaluation of the situation, don’t make us safer. They just make us feel guilty—well, mildly—as we go about our business.

When cars are truly self-driving, like little personal buses, then we won’t even bother to look out the window or close the door when we get in or out.

1. See The Future of Self-Driving Cars from March 12, 2017.

2. I’ve walked through the garage—and I’m a fast walker. It takes time to make a full circuit.

3. Don’t get me started on the Proposition 65 warnings about “chemicals known to the State of California to cause cancer and reproductive harm.” They are posted on virtually every building and enclosed structure because, hey, modern life is full of chemicals. Who among us pauses in thought and then decides to stay outside?