What Is Life?
Every spring in ancient Egypt the Nile River flooded neighboring land, and when it subsided it left behind nutrient-rich mud that enabled people to grow the crops that would sustain them. The muddy soil also gave rise to something else that wasn’t around in drier times: a large number of frogs. The frogs came so suddenly that it seemed they had arisen from the mud itself—which was indeed how the Egyptians believed that they came into being. Medieval Europeans had analogous experiences. Butchers found that maggots and flies would soon appear on meat that had been left out in the open. Barnacle geese, which migrate by night, showed up suddenly on the coast of western Europe, apparently born from flotsam. Mice, too, seemed to generate themselves, in the grain stored in barns. In the seventeenth century a mystic and chemist, Jan Baptist van Helmont, even created a “recipe” for making mice: place dirty underwear in an open pot with a few grains of wheat, and wait twenty-one days. Though the theory was flawed, this was a successful recipe. For most of human history, it seemed obvious that simple living organisms could come into being spontaneously, a process that was called spontaneous generation.
But then different explanations began to emerge. In 1668 an Italian physician and naturalist named Francesco Redi suspected that the maggots that arose on meat—and the flies into which they developed—were due to tiny invisible eggs that other flies had lain. Redi performed one of biology’s first truly scientific experiments to test his idea. He placed samples of snake meat, fish, and veal in wide-mouthed jars, leaving some uncovered, and covering others, some with paper, some with a gauzelike material. He hypothesized that if his theory was wrong, flies and maggots would appear on the meat in all three situations. But if he was correct, they would soon infest the uncovered meat, but not the meat covered by paper. He also expected to see flies buzzing around outside the gauze-covered jar, but not inside it. Later, he expected, maggots would appear on the gauze, and then drop onto the meat below. That is exactly what happened.
Redi’s experiment threw a wet blanket on spontaneous generation, but the idea was not extinguished. With the development and refinement of the microscope, by 1700 people had for the first time been able to see all sorts of unfamiliar life-forms such as bacteria and other unicellular organisms. No one knew where these came from, but most people did suspect they were associated with the spoilage of meats and other foods that went bad. However, there were some who still favored the idea of spontaneous generation, because it seemed proof of a life force immanent in the universe. It could also be taken as evidence of how God could have created life from nothing. And so in 1745 a biologist and Roman Catholic priest named John Needham performed an experiment similar to Redi’s, but on the microscopic scale. Knowing that heat killed the bacteria associated with spoilage, he heated chicken broth for a few minutes to kill anything that was living within it, then let it cool and sealed the vessel. A few days later, the broth showed signs of rotting. An Italian abbot named Lazzaro Spallanzani repeated Needham’s experiments with a stricter protocol for sterilization, and the broth did not spoil. But Needham’s experiment had breathed new life into the idea of spontaneous generation, and the abbot’s more meticulous scientific work was not enough to kill it off.
The belief that there is some sort of essence—a life force—present in the universe was (and still is) appealing to many whose religious or spiritual views tell them that life is imbued with a special quality that can’t be explained by the forces of nature. People had observed since ancient times that living things seem essentially different from the inanimate, so even apart from religious motives, it was natural to see in spontaneous generation evidence of some force that might be the carrier of this essence. About a century after the Needham/Spallanzani controversy, however, Louis Pasteur put the matter of spontaneous generation to rest through careful experiments that provided convincing evidence that microorganisms carried through the air, not born of the broth itself, are what causes broth to spoil.
So what is life? What does it mean to be alive? Deepak approaches consciousness as the foundation of a living universe. His views are reminiscent of a theory known as vitalism, which holds that life arises from a vital principle, or life force, that permeates the cosmos and lies outside the domain of chemistry and physics. If there were a life force that imbued each living organism, then the act of determining what is alive would be on the same footing as, say, that of determining whether an object is a magnet. Just as a magnet is a source of, and responds to, magnetic force, if there were a life force, a living object would interact with it and we could use that interaction to define and measure what is alive. But if there is no life force, then what is it that makes living things “essentially different”? How do we decide what is alive?
Biologists don’t agree on the best way to define life. The living organisms we meet in our everyday world have some common properties, similar to the criteria Deepak gave in chapter 6: they undergo metabolism, which means they convert or use nutrients and energy; they reproduce; they grow; they respond to stimuli, such as when the leaves of a plant turn toward the sun; on a larger scale of time, their species change by adapting their characteristics to the demands of the environment; and they exhibit homeostasis, the self-regulating processes (having to do with everything from body temperature to the balance of biochemical substances in the bloodstream) that allow organisms to maintain a consistent internal state. For example, an ice cube tossed into a swimming pool is colder than the pool, but after a short time, it will melt and warm up, while the pool grows ever so slightly cooler. The forces of heat and cold, in other words, battle it out and come to equilibrium in the form of a uniform temperature. Similarly, a pot of boiling water placed in a cold stream will cool down, while the stream heats up ever so slightly, until the two reach the same temperature. A person tossed into a swimming pool or a cold stream, however, is capable of homeostasis and will maintain body temperature.
Though the above list of properties works well as a definition of life for turtles, redwood trees, and fungi, it is controversial in borderline cases like viruses, self-replicating proteins, and computer viruses. And who knows how exotic lifelike creatures we may someday discover on other planets might fit into our definitions? We’ve already seen that here on Earth, in an arsenic-rich environment, the sacred molecule of DNA operates in an alternate form, in which the phosphorus atoms in its backbone are replaced by arsenic, an element in the same family as phosphorus, yet quite different.
One can make a good argument that biologists don’t need a single definition of life—the solution may be to accept that there are different categories of life, each exhibiting different combinations of lifelike characteristics. A virus may not satisfy all the traditional criteria, rock salt may satisfy just one or two, and a Martian microorganism three, but the details of how we choose to define life are unimportant as long as we are all aware of the criteria each of us is using.
Biologists want to know what makes living things tick, and so they need a definition of life for operational reasons. But here both Deepak and I are interested in a deeper question: what is the relation of living things to the physical universe? That is, if we consider squirrels, redwood trees, and fungi to be alive, and viruses, or even computer viruses, to be at least “lifelike,” what physical qualities distinguish the atoms and molecules those things are made of, from the atoms and molecules in a chunk of metal, or sea salt?
If there were indeed a life force, one could say it instills into each of our molecules a quantum of vitality, making every atom within us alive. We’d be like a cake in which the sweetness of each crumb adds up to the sweetness of the whole. A living being, however, is not as alive as the sum of its parts. Life is what scientists call an “emergent property.” An ocean wave depends on the interactions between many molecules, so to analyze a wave you must understand concepts like temperature and pressure that have no meaning when speaking of just a few molecules. Similarly, it is difficult or impossible, by studying individual molecules alone, to understand what it means to be alive. The atoms and molecules of something that has qualities fitting the definition of life are no different from those in a chunk of metal. It is only their organization that is different.
From the point of view of physics, living things are distinguished through their order, and their ability to maintain it. There are far more ways of rearranging the components in a pot of minestrone soup without destroying its identity as soup than there are ways to rearrange the parts of a cat without destroying its identity as a living thing, and so organization and order are more important to the cat than they are to the soup. Mess with how your molecules are put together, or which organs connect with which, and you won’t last long. When we stop maintaining order, we die, and revert to a highly disordered state.
This idea was first popularized by Erwin Schrödinger, one of the founders of quantum theory, who gave a series of public lectures in Ireland that were published in 1944 as a book entitled What Is Life? I don’t normally quote long-dead physicists, for a couple of reasons. For one, unlike religion, physics does not put much weight on authority. Certainly physicists listen carefully to the arguments of brilliant colleagues, but then we check their equations. More important, because science marches forward, every decent physics graduate student today knows far more than Schrödinger, Heisenberg, Bohr, Planck, Einstein, or any other pioneer of quantum theory ever knew about quantum theory, or any other fundamental theory in physics. And anyone who reads Scientific American knows more about the brain and neuroscience than they did. That doesn’t mean that everything these scientists said was wrong; it just means that not everything they said was right, and for good and understandable reasons.
What Is Life? is famous in part because in it Schrödinger speculated about how genetic information might be encoded in living things. The book was later acknowledged as a source of inspiration by physicist turned molecular biologist Francis Crick, who with James Watson and Rosalind Franklin discovered the double-helix structure of DNA. In tackling the question posed by the book’s title, Schrödinger also offered a pearl that still inspires the way physicists look at life, and describes that outlook very clearly:
What is the characteristic feature of life? When is a piece of matter said to be alive? When it goes on “doing something,” moving, exchanging material with its environment, and so forth, and that for a much longer period than we would expect an inanimate piece of matter to “keep going” under similar circumstances.… It is by avoiding the rapid decay into the inert state of “equilibrium” that an organism appears so enigmatic.
Living things are not like lifeless boulders rolling down a hill: thanks to homeostasis, our fluids keep their precise mix, our internal structures maintain their composition, and in warm-blooded animals, our temperature stays within a certain range.
When I talked about homeostasis I said a pot of boiling water tossed into a cold stream will cool down, while a human being won’t. Of course, if you remain there for too long, your homeostatic mechanisms may be overwhelmed to the point that you develop hypothermia, and eventually die—at which time your body temperature will indeed be the same as that of the water, and you will be in equilibrium with your environment. However, most people will eventually feel uncomfortably cold and get out of the stream. So two of the fundamental characteristics of life are at work in thus resisting the fate of the pot of boiling water—metabolism (which helps you maintain your body temperature, at least for a while) and response to stimuli. That’s life functioning on its most fundamental level—as a complex of energy-hungry molecules temporarily organized in a form that resists the inevitable return to equilibrium.
But the return is indeed inevitable. In this case I happen to believe rather literally what the Bible says in Genesis: “out of [the ground] you were taken; for dust you are and to dust you will return.” Dust is a disorderly conglomeration of all sorts of tiny particles; but in between our beginnings from dust and our end as dust, the universe has given all of us living things the ability to maintain a strict order. For human beings this gift means that, for a time, our cells can stay organized and preserve the integrity of their content; our blood can flow through its proper channels within our bodies; our muscles, organs, and bones can maintain their structure and function. And, most important to our sense of who we are, it means that our brains can operate, and give us the capacity to reason, to store fond moments from childhood, to grow attached to others.
I spoke to my father while writing this book. For as long as I can remember I have feared for his health. When I spoke to him the other night he reassured me that he is alive and well, in the same way he has reassured me each time I’ve seen him over the last twenty years—in my dreams. My father died two decades ago but I’d obviously rather not accept it. I’d rather believe that he has rejoined the universe, or gone on living in some other form. Unfortunately, for me the desire is not strong enough to outweigh the skepticism. Deepak’s metaphysics is not a religion, but like the answers of many religions, his answers are reassuring. It takes special courage to instead believe in science—to face the fact that after death our bodies return to the temperature of the inanimate objects around us, that we and our loved ones reach equilibrium with our environment, that we again become one with the dust.
It takes a huge perspective to know what life is. If life arose from the most basic physical mechanisms that Leonard describes, such as homeostasis and heat exchange, blue-green algae would understand themselves better. But the rich depths of life haven’t been plumbed by science, and that’s what spirituality wants to address. In an earlier chapter, Leonard defended the superiority of science by saying that metaphysics can’t build an MRI scanner. True, but the other edge of the sword is that metaphysics doesn’t build high-tech weapons, either. Science can make life better in material ways, but no one could say that the world is suffering from a lack of materialism; in fact, the world is suffering from the exact opposite: a lack of self-knowledge.
Science could add to self-knowledge by expanding its sights. It could take heed of Einstein’s core belief: “I maintain that the cosmic religious feeling is the strongest and noblest motive for scientific research.” To my way of thinking, Einstein, Schrödinger, Pauli, and other so-called quantum mystics showed real wisdom in honoring the spiritual side of the human mind. After dedicating a lifetime to scientific research they came to the conclusion that spirituality offers a much broader exploration of life than science will ever come to on its own.
So, what is life? Life is the essence of existence. “Essence” doesn’t mean a divine elixir that God poured into the ear of Adam and Eve. Nor is it the “life force” (more about that later). Essence refers to that which is most basic, the thing we cannot take away and still have creation. Evolution has given rise to millions of different forms, but let’s not be distracted because plants and animals look different from stars and galaxies. Life is woven into the very fabric of the universe. You can’t pet a star or walk an electron in the park, but deep down, they are both alive.
Why? Because, as we saw, the universe passes the same tests that biology applies to microbes, viruses, liver cells, white mice, and so forth. Every living creature is born and dies. The physical part decays and gets recycled into new life. Last year’s fallen leaves become fertilizer for next spring’s green buds. (It may make you queasy, but if a dead worm sends nitrogen into the earth, allowing an oak tree to grow, which drops acorns for pigs to gobble up, and you eat bacon for breakfast—well, draw your own conclusion about where your body comes from.) This cycle of rebirth isn’t on automatic pilot, however. If an amoeba dies and decays, its raw materials don’t have to come back as another amoeba. Any life-form, including the human body, can use those materials.
In other words, birth and rebirth are intensely creative. Something old and familiar leads to something new and original. The universe has been perfecting its creative abilities for billions of years. This creative drive is what I would call the “life force.” Leonard maintains that real forces can be measured; some kind of meter, like the electrical meter fixed to the side of your house, must be able to measure it. But the life force is more like the power of imagination. If you measured the calories put out by Leonardo da Vinci’s brain, you wouldn’t be measuring the power of his imagination. His brain happens to give off heat, but that is a side effect, not the real power, which is invisible and immeasurable.
Materialists may tut-tut their disapproval, but forces exist that don’t register on scientific instruments. (The force of desire, the force of curiosity, and the force of love could head the list.) Spirituality argues that creativity lies at the heart of everything that can be called alive. Does that mean that a rock in your shoe is alive? Yes, because it is part of the same creative process that includes you, a process that keeps endlessly emerging with new products. (It is fascinating to note that rocks needed life in order to evolve. The earliest phase of Earth’s history began with 250 minerals, which came as we saw from the dust of supernovas and asteroid collisions. The turbulent forces on the Earth’s crust, including the tremendous heat released by volcanoes, raised the number of minerals to around 1,500. But about two billion years ago living organisms began to process these minerals—feeding off them, and using them to build shells and skeletons. Tiny ocean plankton, whose skeletons are primarily made of calcium, laid down the White Cliffs of Dover and most other limestone formations. Amazingly, living things allowed minerals to keep evolving to reach the present number found on Earth, which is now 4,500—three times the original number. Cosmic evolution has relied upon life as a major cocreator.)
Leonard pleads with us not to fall for the delusions of metaphysics, as comforting as they may be: life is only the interval before dust returns to dust. But science has made a metaphysical decision of its own by putting its faith in matter. To say “We can do away with God” is metaphysics. To say “Life was created only by molecules” is also metaphysics. I’d call it bad metaphysics, actually. Basic physiology tells us that our brains are fed by glucose, or blood sugar. I couldn’t write a word or have a thought without using up molecules of glucose. Yet even if a super-MRI in the future could match a molecule of blood sugar to the exact instant that a neuron fired the signal corresponding to a word on this page, it wouldn’t mean that glucose is thinking.
Let’s say that you track a brain cell back to the atoms that make it up, then farther back to subatomic particles, and finally across the divide into the invisible domain that lies beyond. No one can point to a specific physical process and say, “Aha, that’s where thinking comes from” or “That’s where glucose came alive.” The effort to find such a starting point continues, but materialism is fooling itself. If a young child asked how gasoline learned to drive a car, he would be making the same mistake as some of our leading neuroscientists.
Every molecule that gets transformed into a living process poses an enigma. How does it go from an inert, random state (death) into a vital, creative state (life)? Spirituality takes the approach that nothing is dead. Because we fear our own disintegration and dissolution, we have projected onto death much more power than it actually has. Death is just a transitional stage, as one living form is reborn into another. (I’m not making a religious statement about the soul here, but I will later on.) Materialism can hypothetically trace the path of an oxygen atom in the jet stream until it enters the lungs of a future Michelangelo or Mozart, but it is useless in explaining how that atom is connected to genius, beauty, and art.
In order to explain how matter suddenly becomes part of the dance of life, with all the creativity that life exhibits, you must go to a more essential level. I’ve been arguing that consciousness is innate in Nature. It’s part of our essence. So are the other qualities that distinguish life; intelligence, creativity, organization, and evolution are all essential to living beings. DNA didn’t create them. Saying that DNA creates life is like saying that paint creates paintings. I believe we’ll arrive at the truth by reversing the sequence: life came first, and eventually matter brought it into visible form. Physicist Freeman Dyson points the way to accepting the spiritual viewpoint as part of an expanded science: “I have found a universe growing without limit in richness and complexity, a universe of life surviving forever.”
Some scientists seem to be willing to split the difference. Let biology tell us how life arose, they contend, while religion or metaphysics asks why. This is really a polite form of declaring victory, however, by giving life over entirely to science. Having identified DNA and having set out to map it, genetics is attempting to gobble up everything. There is supposedly a love gene, a criminal gene, even a faith gene. In fact no such genes have been found, and the leading speculation is that they never will be. An apparently simple problem like predicting a child’s height involves more than twenty genes interacting with one another, and even if each of those genes could be isolated, researchers concede that less than half the story would have been told. Why have the Dutch shot up to be the tallest people in the world? Why are the Japanese now among the top ten? Their genes haven’t changed. The answer lies somewhere with diet, environment, an unknown genetic switch, and perhaps an X factor (such as whether the mind can affect the body in its growth. Don’t be incredulous—medicine already knows that psychological abuse can lead to stunted babies, through a process know as psychological dwarfism).
Science keeps getting greedier about the subjects it wants to gobble up. There is no room, as Leonard would have it, for wishful thinking, which we should have left behind in childhood. Don’t talk to me about such fanciful things as intelligence existing everywhere. The best rebuttal I can offer is an eight-year-old border collie named Betsy who lives just outside Vienna, Austria. Betsy’s owner trained her to fetch things by name. If she said “bone,” Betsy fetched a bone. If she said “ball,” Betsy fetched a ball. Any dog owner can tell you this isn’t difficult, but this particular owner was more ambitious. She taught Betsy to fetch dolls, cheese, and a set of keys—until, against all odds, Betsy could understand 340 commands without getting them confused.
Cognitive psychologist Juliane Kaminski tested this phenomenon, which was filmed by public television’s science journal, Nova. Human babies understand about three hundred words when they are around two years old. The next stage in human development, which no other primate has reached, is to grasp symbols. For example, if you hold up a tiny toy car and ask a toddler to find the same thing in the room, she knows that the tiny car is a model, so it poses no difficulty, at around age three, for a child to bring back a bigger toy car. News flash: so can Betsy the border collie. She understands that models represent things symbolically. (I can’t resist mentioning that dogs are the only creatures besides human beings who know what pointing means. At six weeks old a puppy will go to an object if you point at it. At six months old, so will a human baby. But chimpanzees, our nearest primate relatives, cannot. If you point to a cup that hides a treat under it, chimps don’t know what you mean. They don’t catch on even after hundreds of repetitions.)
Betsy isn’t the only smart border collie; at least two others can understand up to two hundred words, which runs counter to almost every old assumption about intelligence, the brain, the evolutionary ladder, and human pride in our exclusive mental abilities. Betsy has one more accomplishment to humble us with. It has long been claimed that only humans can understand abstract renderings. If I show you a picture of a bone, for example, you can run and bring me a real bone. So can Betsy. When shown a picture of any object she knows how to fetch, she goes and gets it. Researchers are left in awe, not before the grandeur of the universe but before an animal who has no right, scientifically, to do what she does. Yet she does it anyway.
Once we open our minds, Betsy can be the wedge to an all-embracing theory of life. The reader faces a clear choice between wholeness and parts. If science is right, life is a puzzle with lots of tiny pieces that, once assembled, turned inert matter into living creatures. If spirituality is right, life is part of Nature’s wholeness, an aspect that becomes visible through living creatures but doesn’t depend on them. The choice you make here reflects your worldview, and the universe will present itself accordingly.
The real problem with the theory of a life force is when it tries to be materialistic. But because it can’t be measured, the “life” part of the life force has no material validity. Ironically, DNA runs into the same objection. I’m well aware that genetics is considered the greatest triumph in modern biology, the breakthrough that made it possible to decode life itself. DNA is the chemical carrier of an incredibly complex message, but it’s not the message itself, any more than the letters of a telegram are the same as the thought that goes into the telegram. Life is Nature experiencing itself in as many different ways as possible. We can choose other words than “Nature.” That’s the message. We can speak of God looking at his (or her) creation, or the universal mind. Each term points toward a self-creating universe that unfolds as a living entity. Spirituality doesn’t need a special moment when life suddenly appeared. Life has always been.