In our culture, we see intelligence as needing a brain or a central processing system. With this brain, there is also the ability to plan and act independently.
Curiously, plants fail this definition entirely. Yet, if you watch a vine find its way through a wire fence, it has no eyes and no brain.
It lacks a map of its surroundings, yet it can find every gap. It redirects itself when blocked and adjusts its spiral as it moves.
The plant’s behaviour looks deliberate because it is responsive. If you pay enough attention, you will find that that response is continuous and precise to the world it inhabits.
A tomato seedling, barely visible above the soil, is already processing dozens of variables.
It learns about competitors overhead by light wavelengths, which tell it to figure out whether there is a friend or a competitor nearby.
This is done through chemical signals from neighbouring roots. The soil chemistry itself determines where the tomato seedling will direct new growth.
When a plant senses damage from herbivores, it fills its tissues with defensive compounds. It also releases airborne signals to warn nearby plants.
When there is a drought, the roots remember, and the memory of that stress shapes how the plant will respond to water weeks later.
No brain and no nervous system are required, and yet information is gathered. The plant’s options are weighed up, and its response is calibrated, and the experience is retained.
This is very much agency, not human agency as we define it, but something older and possibly stranger.
Agency that is distributed throughout the whole organism, one that is inseparable from the environment it inhabits.
The plant doesn’t act on the world from the outside; it acts from within a fluid, continuous, and adaptive relationship with it.
This poses a significant philosophical question. If agency doesn’t need a central processing brain, maybe our idea of agency is wrong or at least incomplete.
Plants have been demonstrating this for 400 million years and we’ve been too busy navel-gazing and looking at ourselves to notice this.
Note next time how the bramble curves around the rock. It’s not done randomly or mechanically.
When looked at from inside, sustained attention. That plant seems very much to be intelligent.