The story of evolution on Earth began at least 3.7 billion years ago, when self-replicating molecules began to compete with each other for survival. These molecules should be thought of as replicators—entities that cause their own replication. What makes these primitive molecules special is not their complexity, nor their delicate internal arrangement of atoms, nor their chemical properties. Rather, replicators attain cosmic significance from their ability to spawn copies of themselves that continue to propagate into the future.
These Spartan blobs of chemistry eventually yielded descendants who have produced languages, discovered laws of nature, and created the greatest works of art in the solar system (at a conservative estimate). The prominent features of these impressive thinkers include relative hairlessness, bipedalism and sexual dimorphism, but their defining characteristic is that they are people—that is, minds that can create new ideas and explanations. While we are biologically human, the far more transcendent aspect of us is that we are people.
But in many circles it has become fashionable to downplay the significance of people and our civilizations. After all, we’ve been around for a mere 200,000 years or so, which is several orders of magnitude less than the total time that life has existed on Earth. To tell the history of the biosphere, so the argument goes, one should give hardly more than a faint nod to Homo sapiens. Any special emphasis on people is due either to naïve anthropocentrism or to a belief in our rightful inheritance of the Earth. But while such inclinations might indeed be faulty, they should not lead us to conclude that people are not the linchpin of evolution on Earth.
Why would anyone consider Homo sapiens more than a mere blip in evolutionary history, given our short time on Earth? The answer hinges on the existence of a second replicator—the meme.
The story of the roughly four billion years between the rise of the first replicators and the dawn of people is an exhilarating tale, full of plot twists, strokes of good fortune and near misses. For example, although life has been churning on for a few billion years, the world was dominated by single-celled organisms like bacteria until only 600 million years ago. In his paradigm-shifting book, The Vital Question, biochemist Nick Lane conjectures that the simplicity of these single-celled creatures prevented the evolution of more complex forms such as plants and animals. Evolution, it seemed, faced a brick wall. It was only when two distinct single-celled organisms—a bacterium and an archaeon— effectively merged that life was able to ratchet upwards in complexity. Lane argues that this symbiotic event allowed the amount of energy per gene of a cell to increase many times over. Though this is still merely a hypothesis, it suggests that the flora and fauna of today owe their existence to an unlikely partnership that was by no means inevitable.
Then there was the infamous meteor strike north of the Yucatan Peninsula about sixty-five million years ago. First proposed in 1980 by a father-and-son team of scientists, Luis and Walter Alvarez, the asteroid impact hypothesis asserts that a meteor larger than Mount Everest collided with Earth at about 50,000 miles per hour. The impact, more powerful than one-billion atomic bombs, must have felt as if Hell itself had rippled outwards until it encompassed the entire planet. “If you were … within 1,000 kilometers,” scientist Joanna Morgan explains, “you would be instantaneously, or within a few seconds, killed by the fireball.” Seconds after the collision, greenery burned up from thermal radiation. Then there were tsunamis and earthquakes. But, without this celestial intervention, our ancestors would probably never have had the opportunity to come out from under the shadow of the daunting dinosaurs.
Compared with page-turning events such as symbiosis and the violent pruning of the tree of life, the six-figure lifespan of Homo sapiens seems trivial from an evolutionary perspective.
But this ignores an entirely new tier of evolution that entered the scene alongside people—that of the meme. The term was coined by Richard Dawkins in his groundbreaking book, The Selfish Gene, in which he defines a meme as “a unit of cultural transmission.” Examples include words, religions, styles of clothing, scientific ideas and technological trends.
Evolution is fundamentally about competition between replicators. So, in the biosphere, variants of a given gene compete to propagate into the next generation. For example, the gene(s) for blue eyes might compete with the gene(s) for brown eyes by providing their host with the benefit of greater attractiveness. If those hosts with blue eyes attract more mates, there will be more offspring with gene(s) for blue eyes than for brown. Over many generations, gene(s) for blue eyes are likely (though not guaranteed) to replace gene(s) for brown eyes. Biologists would then say that blue eyes have a selective advantage over brown eyes.
As people rose up out of the African muck, so did their ideas. The details surrounding the transition from animalistic Homo sapiens to meme-carrying people are not well understood. However, at some point in the past, humans must have begun to host memes in their wetware. Like genes, these memes competed with one another for brain space. But, while the vast majority of genes have no choice but to spread via their own bloodline, from parent to child, memes suffer no such constraint. A far more promiscuous replicator, memes do not discriminate when they choose future hosts. A young person might create a new style of music, or a new method of baking, or a new kind of programming. This idea is not restricted to acceptance by his biological descendants alone. Anyone might pick the innovation up—not just parents and friends, but complete strangers.
Nor are memes confined by the biophysical constraints that limit the number of descendants that a gene can have in the first place. The most prolific mother in recorded history bore 69 children across several decades. A stand-up comedian can spread a novel joke to thousands of ripe minds in a single evening.
Admittedly, memetic evolution is often more difficult to quantify than its genetic counterpart. Linguistic memes are a noteworthy exception, since we can somewhat quantify both the change in words in a given language, and the total number of languages in use at a given point in time. Despite the recent relative homogenization of human civilization, there are still about 5,000 languages spoken today. Given the overwhelming likelihood that most or all are no older than the human race itself, this constitutes an explosion of unique replicators across the planet in a geologically brief time frame. And the evolution of a biological species is glacial in comparison with the branching off of a single language from its mother tongue. Even the most rapid speciation—the emergence of a novel species from a distinct ancestor—occurs on the order of several thousands of years. Yet, as anyone who reads Shakespeare knows, English has dramatically transformed many times over in just the last few centuries.
The evolution of moral memes—ideas about how we ought to behave—has been breathtakingly fast compared with biological evolution. The notion of challenging someone to a duel, once common in the West, is regarded as absurd today. The extension of universal rights to women, ethnic minorities and homosexuals all occurred within the last hundred years or so. While we might quibble about whether this is effective in practice is beside the point. What matters is that the majority of Westerners now accept universal rights as a value in itself, and that the growth of this norm occurred over just a handful of generations.
Finally, memes have the advantage that they may be consciously engineered to propagate. Jokes are one salient example, but there are others. Creators of neologisms often mold new words in such a way that they catch on. A cult leader might spin a web of ideas, rituals and promises that he knows will attract newcomers. Genes, on the other hand, evolve solely through trial and error—they cannot look ahead and predict their own success. People, on the other hand, can design memes to their liking before offering them to the world. Ironically, creationists had a point, but their attention was focused on the wrong replicator!
In any given 10,000-year period, a historian of earthly evolution would conclude that the biosphere had remained largely the same from beginning to end of the period. She would conclude that genetic evolution is real but slumberous. But take the last 10,000 years, and the same historian would have entire encyclopedias to fill. She would notice that a new replicator had come to the fore, and that it was skyrocketing—and continues to skyrocket—past its genetic forefathers. She would explain that these replicators, these memes, had discovered a new method of spreading that could one day take their hosts to the other side of the galaxy.
If evolution is regarded as merely the tale of the change in genes over geological timescales, then indeed people can be left out of the story. But if evolution is viewed as the change in replicators over time, then one must include people as the hosts of a new replicator—the meme.
Let us not be subordinate to memes as all other life forms are to genes. Let us seize the reins from the replicators in our heads, and exploit them to fit our purposes. The future is open. Let’s decide who owns it.