Getting back to evolution, a brain wired by information in the genome to perform computations on information coming in from the senses could organize the animal’s behavior in a way that allowed it to capture energy and resist entropy. It could, for example, implement the rule “If it squeaks, chase it; if it barks, flee from it.”
Chasing and fleeing, though, are not just sequences of muscle contractions—they are goal-directed. Chasing may consist of running or climbing or leaping or ambushing, depending on the circumstances, as long as it increases the chances of snagging the prey; fleeing may include hiding or freezing or zigzagging. And that brings up another momentous 20th-century idea, sometimes called cybernetics, feedback, or control. The idea explains how a physical system can appear to be teleological, that is, directed by purposes or goals. All it needs are a way of sensing the state of itself and its environment, a representation of a goal state (what it “wants,” what it’s “trying for”), an ability to compute the difference between the current state and the goal state, and a repertoire of actions that are tagged with their typical effects. If the system is wired so that it triggers actions that typically reduce the difference between the current state and the goal state, it can be said to pursue goals (and when the world is sufficiently predictable, it will attain them). The principle was discovered by natural selection in the form of homeostasis, as when our bodies regulate their temperature by shivering and sweating. When it was discovered by humans, it was engineered into analog systems like thermostats and cruise control and then into digital systems like chess-playing programs and autonomous robots.
The principles of information, computation, and control bridge the chasm between the physical world of cause and effect and the mental world of knowledge, intelligence, and purpose. It’s not just a rhetorical aspiration to say that ideas can change the world; it’s a fact about the physical makeup of brains. The Enlightenment thinkers had an inkling that thought could consist of patterns in matter—they likened ideas to impressions in wax, vibrations in a string, or waves from a boat. And some, like Hobbes, proposed that “reasoning is but reckoning,” in the original sense of reckoning as calculation. But before the concepts of information and computation were elucidated, it was reasonable for someone to be a mind-body dualist and attribute mental life to an immaterial soul (just as before the concept of evolution was elucidated, it was reasonable to be a creationist and attribute design in nature to a cosmic designer). That’s another reason, I suspect, that so many Enlightenment thinkers were deists.
Of course it’s natural to think twice about whether your cell phone truly “knows” a favorite number, your GPS is really “figuring out” the best route home, and your Roomba is genuinely “trying” to clean the floor. But as information-processing systems become more sophisticated—as their representations of the world become richer, their goals are arranged into hierarchies of subgoals within subgoals, and their actions for attaining the goals become more diverse and less predictable—it starts to look like hominid chauvinism to insist that they don’t. (Whether information and computation explain consciousness, in addition to knowledge, intelligence, and purpose, is a question I’ll turn to in the final chapter.)
Human intelligence remains the benchmark for the artificial kind, and what makes Homo sapiens an unusual species is that our ancestors invested in bigger brains that collected more information about the world, reasoned about it in more sophisticated ways, and deployed a greater variety of actions to achieve their goals. They specialized in the cognitive niche, also called the cultural niche and the hunter-gatherer niche.14 This embraced a suite of new adaptations, including the ability to manipulate mental models of the world and predict what would happen if one tried out new things; the ability to cooperate with others, which allowed teams of people to accomplish what a single person could not; and language, which allowed them to coordinate their actions and to pool the fruits of their experience into the collections of skills and norms we call cultures.15 These investments allowed early hominids to defeat the defenses of a wide range of plants and animals and reap the bounty in energy, which stoked their expanding brains, giving them still more know-how and access to still more energy. A well-studied contemporary hunter-gatherer tribe, the Hadza of Tanzania, who live in the ecosystem where modern humans first evolved and probably preserve much of their lifestyle, extract 3,000 calories daily per person from more than 880 species.16 They create this menu through ingenious and uniquely human ways of foraging, such as felling large animals with poison-tipped arrows, smoking bees out of their hives to steal their honey, and enhancing the nutritional value of meat and tubers by cooking them.
Energy channeled by knowledge is the elixir with which we stave off entropy, and advances in energy capture are advances in human destiny. The invention of farming around ten thousand years ago multiplied the availability of calories from cultivated plants and domesticated animals, freed a portion of the population from the demands of hunting and gathering, and eventually gave them the luxury of writing, thinking, and accumulating their ideas. Around 500 BCE, in what the philosopher Karl Jaspers called the Axial Age, several widely separated cultures pivoted from systems of ritual and sacrifice that merely warded off misfortune to systems of philosophical and religious belief that promoted selflessness and promised spiritual transcendence.17 Taoism and Confucianism in China, Hinduism, Buddhism, and Jainism in India, Zoroastrianism in Persia, Second Temple Judaism in Judea, and classical Greek philosophy and drama emerged within a few centuries of one another. (Confucius, Buddha, Pythagoras, Aeschylus, and the last of the Hebrew prophets walked the earth at the same time.) Recently an interdisciplinary team of scholars identified a common cause.18 It was not an aura of spirituality that descended on the planet but something more prosaic: energy capture. The Axial Age was when agricultural and economic advances provided a burst of energy: upwards of 20,000 calories per person per day in food, fodder, fuel, and raw materials. This surge allowed the civilizations to afford larger cities, a scholarly and priestly class, and a reorientation of their priorities from short-term survival to long-term harmony. As Bertolt Brecht put it millennia later: Grub first, then ethics.19
When the Industrial Revolution released a gusher of usable energy from coal, oil, and falling water, it launched a Great Escape from poverty, disease, hunger, illiteracy, and premature death, first in the West and increasingly in the rest of the world (as we shall see in chapters 5–8). And the next leap in human welfare—the end of extreme poverty and spread of abundance, with all its moral benefits—will depend on technological advances that provide energy at an acceptable economic and environmental cost to the entire world (chapter 10).
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Entro, evo, info. These concepts define the narrative of human progress: the tragedy we were born into, and our means for eking out a better existence.
The first piece of wisdom they offer is that misfortune may be no one’s fault. A major breakthrough of the Scientific Revolution—perhaps its biggest breakthrough—was to refute the intuition that the universe is saturated with purpose. In this primitive but ubiquitous understanding, everything happens for a reason, so when bad things happen—accidents, disease, famine, poverty—some agent must have wanted them to happen. If a person can be fingered for the misfortune, he can be punished or squeezed for damages. If no individual can be singled out, one might blame the nearest ethnic or religious minority, who can be lynched or massacred in a pogrom. If no mortal can plausibly be indicted, one might cast about for witches, who may be burned or drowned. Failing that, one points to sadistic gods, who cannot be punished but can be placated with prayers and sacrifices. And then there are disembodied forces like karma, fate, spiritual messages, cosmic justice, and other guarantors of the intuition that “everything happens for a reason.”
Galileo, Newton, and Laplace replaced this cosmic morality play with a clockwork universe in which events are caused by conditions in the present, not goals
for the future.20 People have goals, of course, but projecting goals onto the workings of nature is an illusion. Things can happen without anyone taking into account their effects on human happiness.
This insight of the Scientific Revolution and the Enlightenment was deepened by the discovery of entropy. Not only does the universe not care about our desires, but in the natural course of events it will appear to thwart them, because there are so many more ways for things to go wrong than for them to go right. Houses burn down, ships sink, battles are lost for want of a horseshoe nail.
Awareness of the indifference of the universe was deepened still further by an understanding of evolution. Predators, parasites, and pathogens are constantly trying to eat us, and pests and spoilage organisms try to eat our stuff. It may make us miserable, but that’s not their problem.
Poverty, too, needs no explanation. In a world governed by entropy and evolution, it is the default state of humankind. Matter does not arrange itself into shelter or clothing, and living things do everything they can to avoid becoming our food. As Adam Smith pointed out, what needs to be explained is wealth. Yet even today, when few people believe that accidents or diseases have perpetrators, discussions of poverty consist mostly of arguments about whom to blame for it.
None of this is to say that the natural world is free of malevolence. On the contrary, evolution guarantees there will be plenty of it. Natural selection consists of competition among genes to be represented in the next generation, and the organisms we see today are descendants of those that edged out their rivals in contests for mates, food, and dominance. This does not mean that all creatures are always rapacious; modern evolutionary theory explains how selfish genes can give rise to unselfish organisms. But the generosity is measured. Unlike the cells in a body or the individuals in a colonial organism, humans are genetically unique, each having accumulated and recombined a different set of mutations that arose over generations of entropy-prone replication in their lineage. Genetic individuality gives us our different tastes and needs, and it also sets the stage for strife. Families, couples, friends, allies, and societies seethe with partial conflicts of interest, which are played out in tension, arguments, and sometimes violence. Another implication of the Law of Entropy is that a complex system like an organism can easily be disabled, because its functioning depends on so many improbable conditions being satisfied at once. A rock against the head, a hand around the neck, a well-aimed poisoned arrow, and the competition is neutralized. More tempting still to a language-using organism, a threat of violence may be used to coerce a rival, opening the door to oppression and exploitation.
Evolution left us with another burden: our cognitive, emotional, and moral faculties are adapted to individual survival and reproduction in an archaic environment, not to universal thriving in a modern one. To appreciate this burden, one doesn’t have to believe that we are cavemen out of time, only that evolution, with its speed limit measured in generations, could not possibly have adapted our brains to modern technology and institutions. Humans today rely on cognitive faculties that worked well enough in traditional societies, but which we now see are infested with bugs.
People are by nature illiterate and innumerate, quantifying the world by “one, two, many” and by rough guesstimates.21 They understand physical things as having hidden essences that obey the laws of sympathetic magic or voodoo rather than physics and biology: objects can reach across time and space to affect things that resemble them or that had been in contact with them in the past (remember the beliefs of pre–Scientific Revolution Englishmen).22 They think that words and thoughts can impinge on the physical world in prayers and curses. They underestimate the prevalence of coincidence.23 They generalize from paltry samples, namely their own experience, and they reason by stereotype, projecting the typical traits of a group onto any individual that belongs to it. They infer causation from correlation. They think holistically, in black and white, and physically, treating abstract networks as concrete stuff. They are not so much intuitive scientists as intuitive lawyers and politicians, marshaling evidence that confirms their convictions while dismissing evidence that contradicts them.24 They overestimate their own knowledge, understanding, rectitude, competence, and luck.25
The human moral sense can also work at cross-purposes to our well-being.26 People demonize those they disagree with, attributing differences of opinion to stupidity and dishonesty. For every misfortune they seek a scapegoat. They see morality as a source of grounds for condemning rivals and mobilizing indignation against them.27 The grounds for condemnation may consist in the defendants’ having harmed others, but they also may consist in their having flouted custom, questioned authority, undermined tribal solidarity, or engaged in unclean sexual or dietary practices. People see violence as moral, not immoral: across the world and throughout history, more people have been murdered to mete out justice than to satisfy greed.28
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But we’re not all bad. Human cognition comes with two features that give it the means to transcend its limitations.29 The first is abstraction. People can co-opt their concept of an object at a place and use it to conceptualize an entity in a circumstance, as when we take the pattern of a thought like The deer ran from the pond to the hill and apply it to The child went from sick to well. They can co-opt the concept of an agent exerting physical force and use it to conceptualize other kinds of causation, as when we extend the image in She forced the door to open to She forced Lisa to join her or She forced herself to be polite. These formulas give people the means to think about a variable with a value and about a cause and its effect—just the conceptual machinery one needs to frame theories and laws. They can do this not just with the elements of thought but with more complex assemblies, allowing them to think in metaphors and analogies: heat is a fluid, a message is a container, a society is a family, obligations are bonds.
The second stepladder of cognition is its combinatorial, recursive power. The mind can entertain an explosive variety of ideas by assembling basic concepts like thing, place, path, actor, cause, and goal into propositions. And it can entertain not only propositions, but propositions about the propositions, and propositions about the propositions about the propositions. Bodies contain humors; illness is an imbalance in the humors that bodies contain; I no longer believe the theory that illness is an imbalance in the humors that bodies contain.
Thanks to language, ideas are not just abstracted and combined inside the head of a single thinker but can be pooled across a community of thinkers. Thomas Jefferson explained the power of language with the help of an analogy: “He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.”30 The potency of language as the original sharing app was multiplied by the invention of writing (and again in later epochs by the printing press, the spread of literacy, and electronic media). The networks of communicating thinkers expanded over time as populations grew, mixed, and became concentrated in cities. And the availability of energy beyond the minimum needed for survival gave more of them the luxury to think and talk.
When large and connected communities take shape, they can come up with ways of organizing their affairs that work to their members’ mutual advantage. Though everyone wants to be right, as soon as people start to air their incompatible views it becomes clear that not everyone can be right about everything. Also, the desire to be right can collide with a second desire, to know the truth, which is uppermost in the minds of bystanders to an argument who are not invested in which side wins. Communities can thereby come up with rules that allow true beliefs to emerge from the rough-and-tumble of argument, such as that you have to provide reasons for your beliefs, you’re allowed to point out flaws in the beliefs of others, and you’re not allowed to forcibly shut people up who disagree with you. Add in the rule that you should allow the world to show you whether your beliefs are true or false, and we can call the ru
les science. With the right rules, a community of less than fully rational thinkers can cultivate rational thoughts.31
The wisdom of crowds can also elevate our moral sentiments. When a wide enough circle of people confer on how best to treat each other, the conversation is bound to go in certain directions. If my starting offer is “I get to rob, beat, enslave, and kill you and your kind, but you don’t get to rob, beat, enslave, or kill me or my kind,” I can’t expect you to agree to the deal or third parties to ratify it, because there’s no good reason that I should get privileges just because I’m me and you’re not.32 Nor are we likely to agree to the deal “I get to rob, beat, enslave, and kill you and your kind, and you get to rob, beat, enslave, and kill me and my kind,” despite its symmetry, because the advantages either of us might get in harming the other are massively outweighed by the disadvantages we would suffer in being harmed (yet another implication of the Law of Entropy: harms are easier to inflict and have larger effects than benefits). We’d be wiser to negotiate a social contract that puts us in a positive-sum game: neither gets to harm the other, and both are encouraged to help the other.