I spent October break in a darkened basement of the medical school, peering through a microscope at butterfly scales. Each scale is a few microns thick, fifty across, and twice as many long: big enough to spot with the naked eye, once you know to look. And each one is formed by a single cell. When the young butterfly is still hidden away in its chrysalis, these scale cells are born all over its wings, and as they grow they stretch tall and wide. They squeeze fibers out through their surface, weaving them together to form a trussed and buttressed frame, hanging sacs of brilliant pigments from its vaults and archways. And then the scale cells commit suicide, leaving behind only their featherweight handiwork, so that the rest may fly.
I look down at my hands sometimes and wonder at them, although they have never made anything so fine or beautiful as those scales, because they are made of and made by many billions of such cells, all working in concert with the same magnanimity. When we were embryos, our hands first grew as fleshy plates, until millions of cells died there to create the empty space that defines each finger. This sacrificial rite is recapitulated throughout our bodies: that I can even see my hands is due to some million cells in each eye that blew apart their own nuclei, forming one lens through which light could shine unimpeded. That I live at all is due to the millions of red cells in my blood that cut out their nuclei, becoming hemoglobinous husks to ferry oxygen to those cells that remain.
They didn’t have to die. If taken from the body and grown alone in a dish, these cells and their progenitors would not be so quick to sacrifice themselves. Nor would some of their siblings, even inside the body: cells can abandon the plan, reproduce like mad, and spread beyond their station, burdening their host with the disease we call cancer.
Seeing the pain that these selfish cells cause and knowing their capacity for altruism, I am tempted to think badly of them. But in doing so, I would be holding them to a higher standard than the one to which we hold ourselves. In our society, we recognize that the sociopath is not the uncaused cause of the evil he commits, and so we conform our jurisprudence and pharmacology to this fact, allowing insanity as a defense from blame and prescribing psychoactives in place of punishment.
We should also be as inclined to praise our cells as we are to praise people. Though we could write off a cell’s sacrifice as merely a response to external chemical flows, in doing so, we would commit another fallacy. The actions of self-sacrificing heroes whom our society celebrates are also brought about by outside forces — what Émile Durkheim called “suicidogenic currents,” the influences flowing from the hero’s companions and growing with the strength of their bonds. I would let the reputations of people and their cells rise with the same tide. When Hamlet or Jesus or Prometheus bleeds, I see his sacrifice reflected in his blood, in those cells’ sacrifice for the body.
Each of us is, in this sense, fractal: an individual and a society. We take for granted what to our cells is a monumental achievement. If we were to build a Colossus as many times bigger than ourselves as we are to our cells, it would be tall enough to high-five the Hubble.
A community with such astronomical reach as our cells’ deserves an anthropology: by what kind of society can such grandeur be achieved, though it demands rampant self-sacrifice? It is a society molded under pressure, surviving and thriving today because it beat out other societies in which cells did not die for the common good. It has been shaped by evolution’s total war.
But it would be a mistake to think that this society is governed by martial law, a sort of biological Third Reich or Airstrip One. Rather, our evolution resembles more the slow refinement of shared traditions — however grisly or unfair — that are adjusted, tried, and proven to better provide a common welfare. Whereas our human traditions reside in our brains, those of our cells reside in their genomes, comprising a shared culture that has supplanted the cells’ former, solitary state of nature to form together a Leviathan. But unlike what Hobbes envisioned, this Leviathan has no monarch at its head: each cell constructs and is equally constructed by the role played by its partners. In our brains, for example, neurons become neurons after being instructed to do so by the cells surrounding them, which themselves become supporting cells. It is aristocracy in the older sense: rule by the best — but not quite. Every cell, not just one empowered class, serves, and must serve, as best befits its position.
But this leaves each cell’s fate predetermined by its lineage. Though ordinary cells can be coaxed in the lab to create a new embryo from which all cell types then descend, any given cell in the body will almost certainly stick to a predictable and specialized life trajectory: if a stem cell in the bone divides, its daughters will make bone. Only on rare occasions, such as severe injuries, do cells sometimes change roles, and almost always in ways that evolution has taught will serve the whole organism.
Only rarely does a cell have its own genetic idea, a mutation of the genomic norm. We are mosaics of several genetically different parts, each part descended from an embryonic ancestor in which a slight mutation occurred. This diversity is most obviously manifest when the mutated genes guide skin pigmentation, creating a literal mosaic of dark and light on the body’s surface. Other cases of evolution go beyond creating mere curiosities: rare skin disorders can improve with age as doubly mutated skin cells reverse the harmful mutation and replace their failing compatriots.
But the degree of diversity in our body’s cellular society is, generally, imperceptible; diversity, like liberty, is not our bodies’ strong point. Only in desperate times will our immune system generate an army of hyper-mutated killer cells to fight infection, and, when quieter times return, these mutated cells are left to wither away. Our cellular society is largely homogeneous, and thriving because of it. Though there are a few known multicellular species of slime mold and fungi that aren’t so strict, they are merely that: mold and fungi. Whereas they allow their cells to split apart and come together as the need arises, our constitution is kept on lock-down from the moment the egg is fertilized, held tight through every division as it reproduces to produce a body’s worth of selfsame descendants.
I’m troubled by all this rigid uniformity and lack of liberty. Our bodies are themselves one of the world’s oldest and greatest civilizations, and I would rather their example inspire a vision for our own future, one concordant with values we people hold in common. But we can at least work to keep our society from being subject to the harsh pressures that pushed our cells to such lengths, and, failing that, take solace in the greatness that might thereby be born.