guest post by Amy Kind
Is there something that it’s like to be plant? I suspect that most people hearing this question would unhesitatingly answer in the negative. In this respect, plants seem quite different from animals. In fact, it’s this difference that undoubtedly helps to explain why so many people who feel squeamish about eating animal products don’t feel at all squeamish about eating fruits, vegetables, and other plant products.
Philosophical assessment of the consciousness of plants and animals is generally in line with this common-sense judgment. Though there’s disagreement about how far consciousness extends throughout the animal kingdom (Are ants conscious? What about garden snails?), and though there’s disagreement about whether and to what extent we can understand the nature of non-human consciousness (can we know, for example, what it’s like to be a bat?), there is general philosophical agreement that at least some non-human animals are conscious. In contrast, very few (if any) philosophers have defended the claim that plants are conscious. Even philosophers such as Chauncy Maher who have recently argued that plants have minds tend not to commit to the claim that there’s something that it’s like to be a plant.
In refraining from this commitment, Maher suggests that the predicate “consciousness” is not determinate when it comes to plants, i.e., there is (currently) no fact of the matter about whether plants are or are not conscious. Maybe they are; maybe they’re not. But given our present understanding of the nature of consciousness, Maher claims that “our standards don’t yet settle whether plants belong in the extension of the term.” When it comes to plants, we simply don’t yet have an adequate understanding of what it would be for them to be conscious.
On this score, however, a recent science fiction duology by Sue Burke helps provide some important insight. Semiosis, the first book in the duology, takes place in the 2060s. Fleeing the wars and environment crises that have engulfed earth, a group of humans united by pacifist ideals travel to a distant planet they name Pax. In their efforts to build a settlement, they eventually come across signs of another sentient animal species on the planet, the Glassmakers. But the Glassmakers are not their only encounter with sentience. As they soon discover, the bamboo-like plant (“rainbow bamboo”) that grows rampant in the area they are settling is also sentient. This plant, whom they name Stevland, initiates communication with the humans and eventually becomes integrated into their society as a full and valuable member – even taking on a leadership role.
We are told even more about Stevland in Interference, the second book in the duology, which takes place about a hundred years after the events of Semiosis when a team of earth scientists travel to Pax to find out what had happened to the original expedition (with whom they had long lost contact). With the more sophisticated equipment these scientists bring, it’s discovered that the rainbow bamboo on Pax has nerve tissue, and that Stevland has a collection of neurons that deserved to be called a brain.
Rainbow bamboo, and Stevland in particular, is clearly very different from bamboo plants on earth. For one thing, earth plants do not adopt names and pronouns for themselves. More to the point for our discussion here, earth bamboo plants lack neurons. Earth bamboo plants also lack the kind of linguistic and emotional capacities that Stevland has, nor can they develop and execute complex and temporally extended plans. But when we set aside these capacities that Stevland has in virtue of his sentience, he nonetheless exhibits a lot of the properties that seem essential or constitutive of plants in general. He relies on sunlight and water, and he is in competition with other nearby plants for these resources. He does not need to sleep. He has a long life span. He is situated in one place with no capacity to move himself to an entirely different place. But he is distributed over a large area, and he can extend his presence to connected terrain. He can survive significant damage to various of his parts and can even survive their destruction. Moreover, such parts can be regrown.
All of these features of plants seem relevant to how they would experience the world. What would give a plant joy? What would make it angry? Given that a plant lacks visual and auditory sense capacities, how would it gain an understanding of its environment? How would it initiate communication? How would it form relationships – whether friendly or unfriendly – with others? Given that a plant lacks mobility, how would it execute plans? How would it strike at its enemies? (Interestingly, and non-coincidentally, Burke herself started thinking seriously about the nature of plant and plant behavior after she witnessed one of her house plants “attacking” another.) Thus, even though Stevland’s neuronal system makes him different from earth plants – so different that, as plant biologist Laci Gerhart has complained, a “scientific reader will struggle with … the seemingly preposterous abilities of Pax’s plant life compared to their terran equivalents.” – the important similarities that he shares with earth plants means that Burke’s exploration of his sentience can help us understand more generally what plant sentience might be like. Unsurprisingly, this was something I thought a lot about as I read the books.
So how does Stevland do the kinds of things just mentioned? Much of his behavior proceeds via his root system. He learns about his environment by ways of his roots. He can extend his roots in new directions, and he does so for many purposes, whether exploring new terrain or connecting and communicating with other plants. He makes additional communicative efforts by generating smells, specific leaf patterns, or distributing chemicals through the production of fruit. His relationships with other plants are driven largely by need. And he has a great deal of patience.
When we think about the features of plants delineated above, this all makes a lot of sense. For example, the relatively long life span of plant species like bamboo – and the fact that they are situated in a single place – suggests that their temporal experience, and correspondingly their patience, would likely be different from that of humans. Moreover, because their situatedness means their only options for relationships are those nearby, we could reasonably expect that plant relationships would be different from human relationships. Here I’ll note that a related point is made by Brandon Sanderson in Cytonic, the third novel in his Skyward series. As a sentient alien from a (non-animal) crystalline species tells the human protagonist: “my species evolved as motionless individuals who would spend decades next to one another. It’s not in our nature to argue. Unlike motile species, we cannot simply walk away if we make one another angry.”
So, is there something it is like to be a plant? Maybe there is, maybe there’s not. Burke’s duology doesn’t really address this question. But in helping us understand something about what it might be like to be a plant if there were something it were like to be a plant, the books pave the way towards a better understanding of the standards we should use in attributing consciousness to other non-human entities. Thus, even if Maher is right that it’s currently indeterminate about whether the predicate “consciousness” should apply to plants, reflections on Burke’s extended thought experiment helps us to make progress in resolving the indeterminacy.
