Review: The Light Eaters by Zoë Schlanger

Passivity is the word that, rightly or wrongly, comes to mind when I think of plants. Plants are shaped by their environment, their forms literally bent and twisted by the elements; plants are done to. By contrast animals do: they are active, they seem to move with purpose and intent (of course there are many animals, particularly marine animals like corals, that seem much more plant-like). US journalist Zoë Schlanger is out to demolish this paradigm in this mind-bending investigation.

Botany, Schlanger writes, is on some kind of precipice, “the most exciting thing to happen to it in a generation”. Driven by findings new and reconsidered, the field seems poised to transition to a new understanding of plants, perhaps even a new conception of plants themselves. Schlanger’s opening chapter considers the question of what a plant actually is, and the answer is more difficult than you might suppose.

This precipitous moment has come about as plant scientists continue to make startling discoveries about how plants experience and act on the world. Chapter by chapter Schlanger shows how plants communicate using astonishingly sophisticated chemical signaling and perhaps also sound, respond to touch and the predations of insects, recognise their kin, seem to transmit information via electrical impulses, remember, and maybe even see. Plants are plastic, they shape themselves to their environment. Even that seemingly most definitive trait of plants, their immobility, collapses under the most cursory inspection — Schlanger pithily points out that a forty-year-old tree is much, much bigger than a forty-year-old human and so had to grow faster. She traces the history of these revelations beginning in the 1980s when scientists wondered if plants were warning each other when they were under attack, and responding by arming their leaves and bodies with bitter chemicals.

At this moment in time when Western thought is still mostly captured by objectivity, categorisation and the separation of humans from nature, these ideas seem astonishing, maybe even transgressive and dangerous, but Schlanger shows that they have a long history. Many Indigenous peoples are very comfortable with the idea of plants being purposeful; so was the Greek philosopher Theophrastus. However, Schlanger argues, the field of plant behaviour (itself a provocative term) was tarnished by ascientific claims popularised in the 1973 book The Secret Life Of Plants. Scientists have continued in or reentered the field at their own peril.

The Light Eater’s is driven by revelation after revelation, but what really impresses is Schlanger’s attention to how such knowledge is produced. She traipses plant places with scientists on the trail of the next discovery that might upend everything — Hawai’i, Chile, rainforests on the Atlantic coast of Brazil and the Pacific coast of the US (places that feel novel perhaps because they haven’t been given the same attention as animal places like the tropical African savannah). Take for instance the Chilean Chameleon Vine Boquila trifoliolata which was discovered in 2014 to mimic the leaves of the plants it clambers over, indeed is so responsive that one vine can mimic many other different plants. How it does so is the subject of intense debate. Some plant scientists argue this is a sign that the vine can see, detecting the form of other leaves through light. Others suggest the shape is being communicated by tiny packets of genetic material transmitted by bacteria. Like Schlanger, I find either possibility completely astonishing. Should the bacteria explanation hold sway, she writes:

it seems time to dim the lights on the idea of plants as individual entities with near borders. Where a plant starts and stops is not clearly understood. It may not even be a useful question.

The thing is, the more you think about plants the more these seemingly crazy ideas make complete sense. Indeed it’s the alternative view that comes to seem bizarre. It’s a matter of perspective, symbolised by the shift in thinking required by the title. What would it mean, Schlanger poses, to see plants not as passively drinking up the sun’s light but actively consuming it, seeking it out? I was particularly gripped by one of the criticisms of a scientific letter about plant intelligence that, if the claims made in the letter were true, then we would have to see the whole plant as a brain. To which I want to cry, yes! what if? After learning that some plants seem to exhibit personalities Schlanger reconsiders her house plants:

were they being silenced? Are these companions who make my apartment feel more alive being deprived of some essential plantness? … I’d probably let my mind travel too far. It’s very easy to do that when thinking about plant agency. Yet — I scolded myself now, confusing things further — what is ‘too far’ when the topic at hand is the agency of living creatures?

This may ultimately be semantical, but Schlanger makes the case that such a shift in language is absolutely critical at a time when our dominant way of life is causing such ruin to nature. With utmost care Schlanger causes us to examine assumptions and prejudices held against plants, and in doing so begins to erode the borders that cause us to be alienated from the rest of nature. Some scientists baulk at the use of terms of human biology to describe plants. But works like Schlanger’s are not so much about elevating the humanity of the more-than-human, but perhaps restoring the nature-ness, the plant-ness, of ourselves.

Gay rating: not gay.