Human Errors

by Nathan H. Lents

  Our impending collapse may be unavoidable, given our evolutionary design. Our desires, instincts, and drives are the product of natural selection, which does not make long-term plans. Chaos, death, and destruction may be the true natural state of the universe and of all species, including ours. To borrow a quote from the legendary science-fiction writer Arthur C. Clarke, “Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying.”

  Immortality Within Our Reach?

  Death is a fact of life for every living thing, and humans are no exception. Nevertheless, humanity has been obsessed with death and how to prevent it—or at least delay it—since the dawn of time. The oldest recorded story in the world, The Epic of Gilgamesh, is about the hero’s quest for everlasting life. In the West, the legends of the philosopher’s stone, the Fountain of Youth, and the Holy Grail center on the secret to immortality. In the East, foundational stories in Hinduism (the Amrita elixir), Chinese medicine (Ling Zhi, the supernatural mushroom), Zoroastrianism (the sacred drink Soma), and many others center on magic that promises everlasting life. Even the Greek word nektar, from the legend of the nectar of the gods, translates literally to overcoming (tar) death (nek).

  If we can’t stave off death, we can at least deny its obliterating effects. Most mythologies and religions center on the afterlife, an abstraction drawn from the very human refusal to believe that this life is all there is and we’ll never see our lost loved ones again. But ironically, this widely shared belief in an afterlife has done little to stem the pursuit of everlasting life. (Is it not odd that Juan Ponce de Léon’s desire to find the Fountain of Youth was in no way tempered by his devout Catholicism, a belief that promised him everlasting life already?)

  Human technology—medicine and alchemy back then and, in modern times, engineering and computing—has been heavily focused on prolonging life. Immortality has always been the biggest prize, and countless prophets, kings, heroes, deities, and adventurers have taken enormous risks in pursuit of it. Today, for the first time, perpetual life may actually be within reach.

  Science has been working hard to reveal the underlying mechanism of aging. As with all things in biology, the process is far more complex than we ever thought. Early research into aging revealed the discouraging truth that aging is caused by the accumulation of random damage to DNA and proteins. I call this discouraging because random damage is very hard to prevent. Modern medicine’s ability to repair damaged tissue is laughable compared with the ability of the body to heal itself. If our own bodies cannot figure out how to stop the cumulative onslaught of molecular damage, what hope do our brains possibly have? The damage is not on the microscale but on the nano scale, and our blunt instruments can barely see it, let alone repair it.

  Nevertheless, new, wholly different strategies to prolong life are beginning to emerge. For one thing, science has wisely given up on the idea that cellular damage is something that physicians can repair. Instead, efforts have largely been focused on understanding how stem cells work and determining whether they can be harnessed. Stem cells are the body’s built-in renewal system for tissues. Stem cells, while few in number, are dispersed strategically throughout most organs and usually lie dormant until called upon. When specialized cells are lost to injury, illness, or mutation, stem cells jump into action and proliferate, producing replacement cells that can then differentiate into specialized cells and begin to function.

  Scientists are finding stem cells in every tissue they examine, and it turns out that the body is more capable of self-renewal than previously thought. It was once considered a canonical truth that every human is born with all the neurons that he or she will ever have and that the gradual loss of neurons in aging adults is inevitable and irreversible. It turns out that the brain has neuronal stem cells that can replace lost or damaged neurons in specific instances. While the information stored by a lost neuron is probably lost forever, the brain does appear able to grow new neurons.

  Stem cells are thus one avenue through which biomedical scientists are attempting to prolong human life indefinitely. If they can figure out how to enhance human stem cells so that they don’t lose the race against cellular damage, we’d have a real chance at living much longer.

  But other, more science-fiction-inspired efforts to prolong life are also under way. Technologies around tissue and organ transplants are developing so rapidly that doctors will soon attempt the transplant of a human head. Actually, this frames it backward. Because an individual’s personality, memories, and consciousness are housed wholly in the brain, this procedure should really be considered a body transplant. If these transplants become successful and efforts to keep brain tissue refreshed and functioning are successful, a person could live indefinitely by simply transplanting her head from body to body. (Let’s not stop to worry about where the bodies would come from.)

  An even more futuristic but perhaps more realistic possibility is the continuing development of xenobiotic and synthetic bionic implants. Beginning with horsehair sutures to close wounds in ancient times and continuing with hooks and peg legs to replace lost appendages in the Middle Ages, humans have long sought to overcome biological limitations with synthetic alternatives. More recently, physicians have advanced from using pig parts to replace failing heart valves to using artificial valves that are sure to outlast their recipients. In fact, scientists have now developed a whole artificial heart that can completely replace its biological counterpart.

  While the current limitations of artificial hearts means that the recipients must await the more lasting solution of a transplant, people have gone for years with something called a left-ventricular assist device, which almost completely takes over the pumping function of the heart. Just a few decades ago, who would have thought that someone could live indefinitely and nearly symptom-free after his own heart had almost failed? That’s exactly what former U.S. vice president Dick Cheney did until he finally received a heart transplant.

  Even our current arsenal of bionic implants reads like the science fiction I grew up reading in the 1980s. Cochlear implantation is now routine, as are arterial stents, artificial hips and knees, and glucose monitors paired with insulin pumps. Already on the horizon are artificial eyes to send visual information directly to the brain, like Geordi La Forge on Star Trek: The Next Generation. The big breakthrough will likely come as we pair our understanding of tissue renewal with the capabilities of nanotechnology. We have nearly all the tools and knowledge necessary to engineer tiny repair robots to scavenge organs for aging cells and recruit fresh stem cells to replace them. It’s only a matter of time.

  Eventually, we may not even need to go to all of that trouble. A new technology called CRISPR/Cas9 has revolutionized science’s ability to safely edit the DNA of living cells. Until recently, the promise of gene therapy was limited by practical difficulties. It seemed impossible and had proved unsafe in even modest attempts. However, CRISPR has changed all of that, and the means to slice and dice our genomes appears tantalizingly close. Biomedical scientists in all fields are racing to see if—or, rather, how—CRISPR can be used to cure disease, repair damage, and renew tissues.

  Genetic testing and counseling have already affected human evolution in this regard. Many people who have a history of certain genetic diseases in their families or ethnic backgrounds elect to get genetic counseling. Couples who discover that both are carriers of a serious genetic illness can choose to go their separate ways, eschew having biological children, or employ amniocentesis to detect whether a fetus will have the dreaded malady. The effect of these efforts is that the prevalence of these diseases in the population is decreasing. This phenomenon will likely be further enhanced through CRISPR. Couples wishing to have a child may one day be able to have their eggs and sperm not just analyzed but repaired prior to fertilization. CRISPR could slice out the disease-causing version of the gene, replace it with the healthy version, and voilà! The technology to do this already exists and wil
l no doubt be tested in fertility clinics soon.

  Even more incredibly, in addition to fixing genetic diseases, CRISPR could easily be used in sperm and eggs to alter the genetics of the planned child to extend his or her lifespan even further. As we come to understand the genetic control of aging, scientists may one day be able to make tweaks to the genes of future generations such that they don’t grow old in the first place.

  Of course, as I noted earlier, the real prize is the search for immortality. As the full picture of cellular aging and tissue renewal comes into focus, we may be able to deploy CRISPR-armed nanobots to fix damaged cells before they begin to show their age. This is not wild speculation. The first steps toward this approach are already being envisioned in animal models. Yes, the initial attempts will be modest, but if they are successful, this genie will never go back in the bottle.

  All the technology I’ve discussed here is nearly at hand, and its arrival in your doctor’s office may be only a few decades away. Certainly, medical technology for prolonging life is developing rapidly even by conventional standards, and for people who manage to stay alive until the deployment of these new measures, doctors may be able to stop, or at least slow, the hands of time. As the technology continues to develop, as it surely will, doctors may even be able to reverse (not just pause) the effects of aging, and individuals will get to live as twenty-somethings forever. This notion is driving many of those near the middle of their lives, including myself, to get in shape and try to “live long enough to live forever,” the prescient subtitle of a book published in 2004.

  Where we will fit all these newly immortal people is another question—but given our species’ tendency to kill one another in large numbers, this problem may solve itself when resources become scarce. Another possibility is the colonization of other planets and moons in our solar system or nearby ones. While this may seem far-fetched because aerospace technology has not developed as rapidly as biomedical technology has, we may be approaching a watershed moment on that front as well.

  The upshot: Never underestimate science or our species’ ability to overcome its own flaws. In fact, many anthropologists credit the development of humans’ impressive ingenuity to the dramatic climate changes that occurred in Africa, Europe, and Central Asia over the past two million years. Biology alone could never have gotten humans through the ice age. We needed cleverness too. And today we are in desperate need of that crucial quality, perhaps more than ever before.

  Coda: Swords or Plowshares?

  While no one knows for sure what the future holds for humanity, we can get an idea by looking at our past. We are a beautiful but imperfect species. What has defined our past will define our future. Because the past is filled with stories of struggle and misery giving way to triumph and prosperity, there is hope that the same will be true for our future. The struggle is clear: Our population growth, environmental destruction, and poor stewardship of natural resources threaten the prosperity that we have sought to create for ourselves.

  What is the answer to that struggle? How can we turn the impending doom into triumphant peace? Simple. By using the same tools and processes that helped us overcome our previous challenges, the same means that brought us prosperity and abundance in the first place: science.

  You might be thinking, Maybe science itself is the problem. Maybe our reliance on science and technology is our ultimate flaw. That’s an understandable suspicion. But I don’t think it’s the reality.

  It is true that scientific progress led to the development of the coal- and petroleum-based energy industry that is devastating the carbon balance in our atmosphere. But science has also provided the solution: solar, wind, water, and geothermal power. It is true that agricultural and textile technologies have led to massive deforestation and tremendous pollution from factory farms. But science has also cultivated the clean crops and synthetic alternatives that could one day phase out their polluting predecessors. The same commitment to scientific progress that conjured coal-powered steam engines has now developed a solar-powered airplane. While every piece of plastic ever made is now sitting in a landfill or on its way to doing so, chemists have created biodegradable plastics, and biologists have engineered bacteria that can eat plastic. Every problem that science has created, science can solve.

  If that sounds overly optimistic, consider this: Green buildings are going up left and right, and we are increasingly meeting our demands for energy and materials in sustainable and environmentally friendly ways. Per square foot, the average American home runs on less than half the electricity annually than it did twenty-five years ago. Per gallon of gasoline, the average new car goes twice as many miles as it did thirty-five years ago. And for both homes and cars, solar and other carbon-neutral power are increasingly pushing down the demand for combustion-based energy. Several European nations have the goal of being carbon-neutral squarely within their sights, and these countries have nowhere near the harvestable sunshine that countries in the Global South have.

  A better future is within our reach. The question is, will we be able to grasp it? Or, to put it a different way: Will our advanced intelligence prove to be our biggest asset or our biggest flaw?

  We already have the science that can save our species from itself. We are waiting only for the will. And if we can’t muster it in time to prevent a global collapse, we will have the ultimate proof of our poor design.

  Acknowledgments

  This book has benefited from the hard work of so many whose names should rightly be on the cover. Marly Rusoff, you gave this project life. As with our previous book together, Tara VanTimmeren took the first pass on everything in this book. Only after it has benefited from her shaping and polishing do I ever dare send a manuscript to anyone else. From our first breakfast meeting, I knew that you were “the one” and I immediately trashed the list of agents to whom I had planned to pitch this. You took my scattered thoughts and helped me produce a coherent manuscript from them. Bruce Nichols and Alexander Littlefield, you both have been incredibly insightful editors whose contributions have improved this book tenfold. Thanks to all four of you talented editors for believing in this project and bringing the skill and professionalism needed to transform it from a nice idea to a finished book. Tracy Roe also deserves buckets of praise for her spectacular eleventh-hour contributions to this manuscript, which strengthened it immeasurably. This book really was a team effort and it was humbling to work with people of such intellect.

  I must also acknowledge the work of the incredibly talented artist whose playful but illuminating drawings grace these pages. It was so gratifying to watch Don Ganley take my often vague and unhelpful guidelines and make wonderful illustrations from them. His art really brings the content of this book to life. I hope you take a minute to fully appreciate these drawings. Each one is the result of many hours and many revisions. It took Don like three hours to finish the shading on the upper lip of the skull in the figure on page 11. It’s probably the best drawing he’s ever done.

  And to my students, my friends, and my family, thank you so much for letting me drone on and on about these topics over the years. I always strive for a writing style that is best described as a fun conversation with a friend; that is to say, I try to write as though I am talking with you. If you have ever indulged me in a conversation about any of these topics, you unwittingly helped me write this book. And for that, I cannot possibly thank you enough.

  As with everything else I do, this book would not have been possible without the support of my family, whose patience was surely tested over the years that I, among the most flawed members of our species, worked on this manuscript. Oscar, Richard, Alicia, and, of course, Bruno, thank you for the encouragement. I love you.

  Notes

  1. Pointless Bones and Other Anatomical Errors

  30 to 40 percent of the population: Seang-Mei Saw et al., “Epidemiology of Myopia,” Epidemiologic Reviews 18, no. 2 (1996): 175–87.

  migrating birds detect: Thorsten Rit
z, Salih Adem, and Klaus Schulten, “A Model for Photoreceptor-Based Magnetoreception in Birds,” Biophysical Journal 78, no. 2 (2000): 707–18.

  For a human to achieve: Julie L. Schnapf and Denis A. Baylor, “How Photoreceptor Cells Respond to Light,” Scientific American 256, no. 4 (1987): 40.

  how long the RLN must have been: Mathew J. Wedel, “A Monument of Inefficiency: The Presumed Course of the Recurrent Laryngeal Nerve in Sauropod Dinosaurs,” Acta Palaeontologica Polonica 57, no. 2 (2012): 251–56.

  Japanese fishermen caught a dolphin: Seiji Ohsumi and Hidehiro Kato, “A Bottlenose Dolphin (Tursiops truncatus) with Fin-Shaped Hind Appendages,” Marine Mammal Science 24, no. 3 (2008): 743–45.

  2. Our Needy Diet

  the GULO gene suffered a mutation: Morimitsu Nishikimi and Kunio Yagi, “Molecular Basis for the Deficiency in Humans of Gulonolactone Oxidase, a Key Enzyme for Ascorbic Acid Biosynthesis,” American Journal of Clinical Nutrition 54, no. 6 (1991): 1203S–8S.

  Take fruit bats: Jie Cui et al., “Progressive Pseudogenization: Vitamin C Synthesis and Its Loss in Bats,” Molecular Biology and Evolution 28, no. 2 (2011): 1025–31.