Missing Character   /   Spring 2024   /    Notes & Comments

A Carrier Bag Theory of Biology

Neither resolution nor stasis, but continuing process.

Lee Cooper

W.S, Merwin at The Merwin Conservancy, photograph by Tom Sewell.

He began by digging a hole. Then he placed the first seedling, surrounding it with manure-rich compost and watering it by hand. He worked with patience, urgency, and skill. One tiny tree at a time. Always with ample compost and water.

The man, W.S. Merwin, moved to Hawaii’s Pe’ahi Valley in 1976, five years after winning his first Pulitzer Prize for poetry. Merwin knew that his plot of earth had been all but stripped bare by the previous stewards, commercial pineapple planters. It contained little more than a monoculture of brittle, invasive grass. His intention was, with help from his wife, Paula, and others, to grow palms and restore the soil.

As seedlings became saplings, bacteria and fungi took to the roots, enriching from within. Decaying biomass recycled into the earth. Dust turned to soil. Fertile ground was born from the work of decades, then a palm forest. “The moment you get the canopy back and can get any trees to grow, the trees begin to make forest conditions,” the poet said in a 2016 documentary, W.S. Merwin: Even Though The Whole World Is Burning. “You can’t plant a forest, because the forest is an ecosystem that no human being can understand.”

The nineteen-acre Merwin Conservancy is not the wild, native forest that might have existed before the arrival of the pineapple planters. Merwin’s forest includes both local and far-flung species of palm. As is noted on its website, the conservancy protects “one of the largest and most extensive palm collections known to exist on earth,” including several endangered species. It is a garden, and a forest, and a vessel in which life can flourish.

Merwin died in 2019, leaving a legacy of language and land enlivened by his care for the words and bodies from which emerge a poem or a forest. The aesthetic and moral power of his lifework offers essential wisdom for an era increasingly defined both by extraordinary biotechnological power and unprecedented challenges to the sustainability of our biosphere.

As Merwin appreciated, a tree lives in a space that meets a narrow band of chemical and physical criteria: suitable temperature and moisture, neither too much nor too little acidity, carbon, and nitrogen, and so on. A tree needs that environment, and it also helps create it. Once chopped down, a tree can’t be unchopped. Similarly, the forest becomes forest, and continues becoming as a forest, because it has found a place in the universe where someone—or no one—has packaged a set of elements that, when combined in the right amounts and in the right sequence, allows for that forest-scale emergence of life.

We, too, emerge. We emerge as bodies of cells. Cell, the word, is derived from the Latin cella, which means “small room.” A room is a sort of vessel. Cells are vessels that emerge out of improbable recipes of salt-, fat-, sugar-, and acid-based components. These components are transformed into life by their coordinated maintenance and asexual reproduction. The cell replicates its order into sibling cells, for there is work to do together. Only together can they organize into organs and organisms.

I’d like to offer that primary vessel, the cella, as the centerpiece for what we might call a carrier bag theory of biology. The idea of the carrier bag comes from the work of the novelist, essayist, and poet Ursula K. Le Guin. In a 1986 essay, she borrowed from anthropology to describe a “Carrier Bag Theory of Fiction.” For Le Guin, a carrier bag holding many narrative vectors represents a “whole which itself cannot be characterized either as conflict or as harmony, since its purpose is neither resolution nor stasis, but continuing process.”

One man with a spear hunting a mammoth may be an easier story to tell than that of a group gathering grain in satchels, but it is also limited in its explanatory and creative power. The allure of a single hero’s violent conquest need not overshadow the more complete and subtle story of communal life that enables the hunting party to venture out in the first place.

Similarly, we tend to base our understanding of our biological origins on the spear-like double helix of DNA, with its false clarity, rather than a membrane-bound bundle. DNA casts a kind of spell, more alchemistic or mystical than scientific: the hypnotic spiraling of a secret code. It is easy to visualize DNA as a discrete and enduring thread of information. An ephemeral, cellular sac presents more of a challenge. Yet DNA is not alive and is not strictly necessary for life. DNA itself is inert and plays no active, executive-like function; its code must be interpreted in the context of a living cell for it to have any meaning. Funny, isn’t it, that life is not at the center of the most ubiquitous metaphor for living systems?

The symbols we use to envision and communicate science matter. A carrier bag theory of biology is about far more than a superficial preference for cells over DNA. The metaphors we imagine become the lenses through which we identify problems, attempt solutions, and pursue the truth in its many forms. Cells’ stories are ones of survival and procreation: encountering dynamic environments, adapting, cooperating, overcoming conflict from within.

It is different to move through the world with a view of oneself as an emergent being, rather than as the inevitable instantiation of genes. We might build different tools—and shape a different world—with stories that shared a default view of life as embodying survival over stasis, communal redundancy over individual efficiency. A cell-centered biology of emergence is likely to be a more contextualized study of life and its parts. As agronomist and essayist Wes Jackson has written, “The sequence of amino acids that is at home in the human cell, when produced inside the bacterial cell, does not fold quite right. Something about the E. coli internal environment affects the tertiary structure of the protein and makes it inactive. The whole in this case, the E. coli cell, affects the part—the newly made protein. Where is the priority of part now?”

The study of life requires studying parts, the relations among parts, and the relation of the emergent whole to other wholes. Using cells as our ethical lens on the natural world helps us to unlock more seamless thinking up and down different biological scales, from cell to organ to organism to population to ecosystem. A DNA-centric view does just the opposite: In confusing heredity for life, it atomizes life at each scale, rather than revealing an emergent continuum.

Underestimating this continuum from cell to ecosystem handicaps our abilities to appropriately engineer biological systems, whether for human health or climate-resilient agriculture. DNA as the carrier of life is an abstraction that reduces the aliveness of biology. It leads to the sort of thinking that sees a forest as a collection of trees, or a person as a mosaic of coding, protein, and fat. Such views bias decision-making away from a reverence for the living whole.

Life-diminishing abstractions make it easier to forget that bioengineering is less of a modular and scalable process than some bioengineers might wish it to be. When researchers attempt to use DNA (or its livelier cousin, mRNA) as a medicine, they find that optimizing the code can cause quite a bit of trouble. Evolution has led to redundancy, so that there are near infinite ways that any given biological message might be encoded. In attempting to optimize any one sequence, we confront the unknowable depth and breadth of cellular and organismal context.

To internalize the cell as it is—imperfect and changing—is to tie more of our choices to the ambition of creating the right conditions for life to thrive, from cell to ecosystem. We cannot plant a forest, but we can try to know what it takes to nurture the trees until they form a canopy and, eventually, enable additional scales of organic life.

In The Song of the Cell, physician and science writer Siddhartha Mukherjee recently offered a provocative thought experiment for the field of regenerative cellular medicine: the Delphic boat. The boat is made of many pieces of wood, each of which is eventually replaced in the course of multiple repairs. Even though none of the boat’s original wood remains, its form is not otherwise changed. Is it the same boat? Humans may soon become a bit like the Delphic boat in a superficial sense, infused with the buzz of fresh cells to repair or strengthen our bodies. But at its core, the metaphor of the Delphic boat is a reductionist one, and the remarkable clinical success of some early living cell therapies relies on the reality that bodies are not inanimate boats, and cells are not inanimate pieces of wood. And nor are forests, nor topsoil.

It may be that social and political disputes over the use of genetically modified organisms or the safety of mRNA vaccines turn, at least in part, on reductionist erosion of the wholeness of life. Deeply embedded, DNA-centric perspectives can distort how we intuitively categorize such technologies. It is unwise to make blanket practical or ethical decisions covering many different gene manipulation technologies, each with its own set of potential risks and benefits to whole cells, to whole people, and to whole populations.

A carrier bag theory of biology could help us move science communication and policymaking beyond existing patterns at a time when the perils posed by global pandemics, mass extinctions, and biotechnological breakthroughs are particularly salient. Deconstructing a thing into its constitutive pieces is necessary for acquiring a certain type of knowledge, but the challenges of today demand a problem-solving ethos that explores both the parts and the whole. At once an emerging complex and the basic unit for all other living systems, the cell is uniquely suited to hold this tension.

The uncertainty of life is as beautiful as it is frightening. It is something wild. Mammalian placentas exist because the genes of ancient viruses somehow integrated into premammalian cells, creating the conditions for a new organ to safely grow life within itself. Similarly, neuronal signaling particles that underlie higher thought originated from yet other viruses that merged into our ancestors’ cells.

Contemplating the meaning of wildness, Merwin once noted, “The wild is a sense of something that just got away from you, something that you can’t ever really hold onto…something terribly important to you and you can’t grasp it.” And, he added, “if we lose respect for that, then we get self-important.”