The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth

By Zoë Schlanger. Harper, 2024. 304 pages. $29.99/hardcover; $19.99/paperback; $14.99/eBook.

The debate in the scientific community over the question of plant intelligence is fierce these days. Zoë Schlanger—who left an increasingly dreary job as an environment reporter to explore her unexpected and growing passion for plants—spent years researching this book and following individual botanists and their experiments all over the world. (She’s now a staff writer at The Atlantic, where she covers climate change.) As readers, we get the great gift of her clear-eyed descriptions of their work and her evolving perspective on this debate.

We learn that plants can feel—having electrical impulses run through their bodies when one part is wounded—in a system very like our nervous system. They can choose, as they have root ends moving unerringly both toward water and away from blockages or danger. They can remember, as they expect and prepare for the return of a pollinator. They can act in solidarity, by picking up the acoustic vibrations of caterpillars munching and then sending out finely tuned chemical emanations to alert their neighbors. Plant seeds can decide: to stay safe and enclosed on the one hand, or to risk the commitment of sending out a root on the other.

In a very sophisticated act of camouflage, a vine in the Chilean rainforest adjusts the shape and color of its leaves to mimic whatever plant is closest. Could this vine have some kind of vision that is beyond our understanding, or is a community of microbes somehow transmitting information from its neighbors? Scientists don’t know. Regardless of what they might ultimately prove, the flexibility and agency on display here is stunning.

Schlanger notes that human beings have defined what “intelligence” is and identify our species as the norm. Since our intelligence is organized, to a large extent, in our brains, the existence of a brain has become the definer. If we can’t locate what we can recognize as a brain in plants, then we are led to ask, how can they be intelligent?

But what if the real issue here is the limitation of our capacity to venture outside our own paradigm? As highly mobile mammals, perhaps we needed to centralize our intelligence. What if a plant, interacting with sun, weather, other life forms, and soil—all from one point in space—has an intelligence that is distributed throughout its whole body?

The Western mind, seduced by the lures of domination, has long struggled with equality. Scientific theories claiming the innate superiority of White men were only definitively debunked in the last century. We have since come to understand the deep intelligence of our primate relatives: of other mammals, such as rats, dogs, whales, and dolphins. Even more recently, we’ve been initiated into the mysteries of octopus intelligence.

The journey is far from over. We’re still reaching for social equality for Black people and women, to say nothing of other mammals, and we still eat octopus. But the trajectory is clear. New discoveries of Western science keep challenging human exceptionalism and bringing us closer to the Indigenous understanding that we live among relatives. Schlanger is passionate in her suggestion that plants are among those relatives.

Her overall plea is that we pry open our minds to the wonders of plants. If the rigidities of our anthropocentric framing can’t permit us to welcome plants as fellow intelligent beings, perhaps we can take a step forward by using adjectives when we talk about plants: plant memory, plant sensation, plant communication, and plant choice, thereby acknowledging plant intelligence.

Though she only touches on it, basing diets on the sentience of what we eat is challenging to me. While I’m committed to challenging the centrality of meat in our diets—both on the grounds of cruelty and its impact on Earth—I have to wonder: Can we continue to kill plants and eat them without a second thought? Of course, we need to eat, but I hope we can dig a little deeper, acknowledging that we depend on other sentient members of this web of life in which we’re embedded to keep us alive. The central issue then becomes not what we end up eating but the spirit in which we eat it and how we acknowledge reciprocity and express gratitude.

Ultimately for our lives, we are totally dependent on plants for their ability to transform sunlight and water into sugars. We owe them deep thanks and great respect. Perhaps we could have their companionship as well. This book, deeply rooted in both science and wonder, challenges us to expand our Quaker values around equality. Its message is a critical one for the future of all life on Earth.

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Pamela Haines is a member of Central Philadelphia (Pa.) Meeting. Author of Money and Soul, her newest titles are Tending Sacred Ground: Respectful Parenting; The Promise of Right Relationship; and a third volume of poetry, Tending the Web: Poems of Connection. Her blog and podcast can be found at pamelahaines.substack.com.