Book Review: The Light Eaters
This book is journalism — the innovative, creative kind that rose to prominence in the 1960s and 1970s: Honouring its obligation to represent people, ideas and events as accurately and fairly as possible, it show a new “literary” concern with setting, characterisation, and author’s distinctive traits. In The Light Eaters: The New Science of Plant Intelligence, Zoë Schlanger has turned many fairly small independent stories into one large one. Emphasizing common ground among a selection of experiments-in-progress, she suggests that the old, relatively conservative science of botany is on the cusp of a new paradigm, a “revolution” (She has read Thomas Kuhn, The Structure of Scientific Revolutions, and makes the claim with care and deference). Having chosen experiments that are open-ended, suggestive, and — to her — thrilling in their potential implications, she takes us along to meet the people, see the settings — whether laboratory or jungle — and hear the ideas. And she keeps reflecting on what she’s learning, sharing the terms and outlining the conflicts the new research tends to generate, both within and outside its immediate scientific audience. At a minimum, she has delivered a very strong challenge to anyone’s usual assumptions about plants, and perhaps, by facilitating some level of understanding among those of us who are not scientists, she has effectively supported the research.
It’s an ambitious, potentially risky venture for a professional journalist, even one with a strong educational background in science and long experience in reporting recent environmental change. In the book, she moves through highly specialised fields at a brisk pace: science, history of science, philosophy of science and anthropology, gender studies, and more. It would be easy to overlook, misunderstand or omit things, easy to offend. Perhaps it’s a journalist’s respect for language — or a writer’s love for it. She stitches the many parts of the project together with a fairly small cluster of concepts, e.g. “agency,” “memory,” “consciousness,” all features we would are unlikely to attribute to plants, but would surely attribute to ourselves. They begin to function as leitmotifs. Arguably the most comprehensive of these, and the one she chose to use in her subtitle, is “intelligence”. Are plants intelligent?
Plants do not have brains in the same sense we do — there’s general agreement on that point. But must intelligence depend on a brain? No less an authority than Charles Darwin, in experiments undertaken with his son Francis, showed that a plants reliably adjust the direction of their roots’ growth to avoid an obstacle before actually encountering them. In some sense, then, they plan ahead. “It is hardly an exaggeration,” they wrote, “to say that the tip of the radicle acts like the brain of one of the lower animals.” (The Power of Movement in Plants, 1880.)
It is by now fairly well-accepted that plants sense when their leaves are being chewed by insects, and produce chemicals to defend themselves, either by making their own leaves distasteful to the insect or by “notifying” that insect’s known predator. Such an active, self-protective response to changes in one’s environment might well be considered intelligent behaviour. There is quite a lot of evidence that plants send warnings of impending danger to one another, and some research suggests that they give their own specie or close relatives priority over others as recipients of such messages. Some plants appear to hold patterns of daylight and darkness in memory, adjusting within a day to significant shifts. Surely among the most startling behaviour Schlanger describes is that of Boquila trifoliolata (she calls it, “the chameleon vine”), which can change its shape in imitation of another plant in its immediate vicinity. The ecologist Ernesto Gianoli, a professor at Universidad de La Sirena, Chile, had, by the time of writing, established 20 different species of plant that Boquila could imitate, but the list was still growing.
In light of the evidence Schlanger offers, readers may find themselves projecting the possibility that plants are conscious, sentient beings with lives and relationships, pains and pleasures. From some standpoints, this is not news. Aboriginal people all over the world have not only credited plants with agency and character and a capacity to communicate with one another, but often held them in awe, deferred to them, cultivated distinctive relationships with them. I can testify to one particularly rich and detailed example — and Schlanger cites it — compiled by three generations of Ojibwe women (natives of a the Great Lakes area, spanning the border between the US and Canada) https://diggingenglish.com/dandelions. Some might say, then, that science is at last beginning to understand what others have known for centuries.
From another standpoint, however, describing plants in terms of human capacities such as “agency” or “consciousness” or “intelligence,” is potentially confusing, likely to interfere with clear thinking and careful observation of phenomena that are not similar to us at all. “I wonder,” Schlanger writes, “instead of humanizing plants, could we not just vegetize our language?” (p.250)
It’s at attractive solution, certainly, and characteristic of the energy and optimism in Schlanger’s voice. In suggesting “plant-memory, plant-language, plant-feeling” by way of examples, though, I wonder whether she isn’t liding past what would seem quite enormous difficulties in developing concise equivalents. Her enthusiasm is infectious, and we absorb it through her language: it is never far from an underlying belief in a fundamental connection between human beings and all other beings, and a conviction that we can only really know and appreciate ourselves to the extent we appreciate our relationships to, interdependence with other kinds of beings. Her language is nothing if not inclusive. Even the index is exceptionally rich and welcoming. Can an index be “empathetic? I suspect Schlanger prepared it herself. Whoever did write it seems to have made a given entry — whether idea, person, or plant — accessible in various ways, emphasising — in keeping with the book’s overall message — connectedness over containment. The words that seem to me the books “connective tissue,” like agency and memory, aren’t in the index, though. They’re the ones that don’t stay on the page, but start to affect a reader’s own structures of memory, thinking, and speaking.
