The classification of a living being as “plant” does not exclude consciousness. In fact, most contemporary definitions hinge upon plants’ particular cellular formations, and their ability to photosynthesize. Earlier definitions emphasized plants’ rootedness, their inability to be mobile the way animals were – but even that definition is not precise. Regardless, there is no intrinsic reason that plants cannot, in addition to their other characteristics, also possess some kind of consciousness. Indeed, recent research continues to move in the direction of concluding that plants not only behave purposefully, but also transmit “messages.”
Such messages might seem to some a loose interpretation of the concept, and it does rely on the assumption that ‘communication’ of any kind requires mutual (if imperfect) interpretation, and not just a stimulus and response. Such a definition applies to human communication as well; we may not fully understand each other, but we intend to understand, interpret and ultimately derive meaning from one another’s utterances, or “signs.”
We know that plants “communicate” with each other, in that they convey and receive seemingly purposeful signals. The signals are more than just reflexes – one thing moving or influencing another thing. Ecologist James Cahill says that there are obvious “strategies” in inter-plant or plant-environment communication. “Plants can’t run away, so they have to develop other strategies to stay alive,” suggests one article describing his argument. The signals manifest through the use of chemicals, but the chemicals are not mere tools; rather, they are signal-tools.
The most remarkable fact to emerge from the discovery of plants communicating with other plants or with other parts of their environment is the idea that they “cry for help” or in general express “distress” over being eaten by bugs and other creatures. Although “suffering” is certainly an anthropomorphic concept, the data suggests plants do the plant-equivalent of crying for help, eavesdropping on other plants being eaten in order to strengthen their own defenses, and tell animals they can nest in them in order to benefit from animal waste. These may not be unmistakable acts of sharing meaning and interpretation, but they are more than mere impulse-motion.
So can humans ever create meaningful communication with plants? What would this entail? Communication is about signaling. Signs, signals, referrals, indications – everything is part of a complex “web of signification.” For logician Gottlieb Frege, the meaning of a given sign is a function of its relationships within that web. That relationship is articulated through interpretation – the receiver receives the message and assigns it meaning. The subjects in communication, individual and collective, interpret others (and their own) signals. This interpretation is always imperfect (the late postmodern philosopher Jacques Derrida believed language had to be problematic for communication to exist at all), but we do it anyway.
So while we have exchanged electronic signals with plants, I don’t believe we’ve established anything close to “communication” with them, because although we are “interpreting” their own outward directed gestures (electrical currents, the generation of sounds) as “signals” of biological need or distress, we have no idea whether they are framing those phenomena as signals, and we can’t really distinguish them from the messages they are already sending to other plants and non-human life. And do plants collect and organize data?
New research casts some skepticism: a “team of Singaporean scientists discovered that communication between plants and humans is possible by tracing electric signals diffused by plants.” Since we can barely call the electric sensations “signals,” and there is no evidence of interpretation going on in the plants (only reflex), we have to decide that the evidence is inconclusive. Likewise, the fact that humans can send electronic sensations that make plants do things (shrink back, move, grow faster or slower) indicates that humans have established a level of mechanical control over plants, not that we can communicate with them. The article about the Singaporian experiment goes on to say that “signals can be controlled [by humans] to broaden the plants’ abilities and functions.” We can interpret their signals, but our signals back to them are just attempts to technologically control them. It lacks the reciprocity of created meaning, or at least we are not seeking the plants’ messages for themselves.
Some of this is definitional and some of it is biological. Brains transmit meaning through neurons, and plants don’t have neurons. Plants seem to transmit electrical signals, but to what end we don’t know.
But it’s important to emphasize that “we don’t know” is the real takeaway. We don’t know that the sensations being transmitted are interpretable or convey meaning in any way similar to what we think meaning is. There are also as-yet-unexplained data that raises more questions, like the “clicking” that one writer’s plants made when she was alone in a room with them (and listening to their roots through special microphones), clicking that stopped when visitors entered the room, started up again when they left, then stopped when more people entered the room. This could be a very sophisticated reflex, but could also be a purposive response of some kind. Scientists admit that to say the clicks are communicative “requires further evidence.” After all, response to stimuli is only the very basic root element of communication – necessary, for sure, but not sufficient.
Although not everyone will recognize it as such, the question of whether humans and plants could actually communicate is an important one. The stakes are high both philosophically and practically. Philosophically, it makes sense to see whether we can communicate with radically different living beings here before figuring out how we’ll communicate with extraterrestrial beings. Being able to “stretch” ourselves across kingdoms is the ultimate test of our adaptability. And perhaps actually communicating with plants would teach us something about how the rest of the living world orients to time. Practically speaking, “early detection of diseases in crops could result in high food security for us humans,” and what better way to check for those diseases than to ask plants how they are feeling and receive an answer.