We talk a lot about thinking, but rarely think about what thinking really is. René Descartes, a 17th century French philosopher, thought he had brought the subject to a close with his conclusion that, “I think, therefore I am.” But his position was countered by the 18th century French philosopher, Jean-Jacques Rousseau, who contended that,“I feel, therefore I am.” But all this speculation was centuries ago, without either having access to the wealth of neurological and cognitive evidence available in the 21st century.

What Descartes overlooked was the rather obvious fact that without a body, the mind could not exist. And what Rousseau overlooked was the other obvious fact that without a mind, the body could not exist. Neuroscience is attempting to resolve this paradox, and an interesting place to begin an exploration of this subject is in Clayton Page Aldern’s 2024 book, The Weight of Nature: How A Changing Climate Changes Our Brains. Of particular interest to the mind/body issue is the Prologue, called Tension, because it provides an overview that explains the striking connection between mind, body and ecology. Indeed, the three are inseparable: the thing we call mind is the brain functioning in concert with the body, and the thing we call body is our senses functioning in concert with its natural surroundings.

The most important thinking that we do is a process of constant modelling that takes place between the body and its outside environment. Without this modelling, the body would be constantly encountering totally unpredictable events for which it would be completely unprepared to respond, and it would not survive for long. Besides, without a body, the brain would not be able to think. So, what the body is doing, via sensations that stimulate feelings, is sending information to the brain so it can predict and be prepared for what happens next. Our survival depends on the up-to-date accuracy of this information. Is the situation safe or dangerous, cold or hot, wet or dry? Where does the body get food, water and shelter? All this depends on a constant modelling of the outside world, a mapping that makes us feel comfortable by knowing that this follows that, that one thing is connected to another, that things stay in their anticipated places.

“The goal,” Aldern writes, “is to minimize the mismatch between what you expect to experience at any given moment and what you actually experience. It’s the only way you can exist continually in time. If your brain didn’t seek to minimize surprises, you’d be pathologically dumbstruck, every moment of every day. You would forget that people generally have two arms; you would be terrified to learn your hands are attached to your body, and that the sky is such a remarkable shade of blue. But instead of [confronting] a constant nightmare, your model learns to expect these kinds of things so it can focus on the interesting stuff”—like Descartes thinking about thinking, Rousseau thinking about feelings, and you wondering why you are reading these words.

Feelings are the emotions that we assign to bodily sensations, the experiences that give meaning to our lives. “Much ink has been spilled,” notes Aldern, “in service of the notion of regulating our emotions. It’s all roughly backward. The thing we are designed to do is let our emotions regulate us. Success in living means listening to your body.” The one thing the brain does not do is function in isolation from the body. “The stuff of thought is physical stuff. It is exposed to the world, and it makes itself in its image.”

So what happens when the world itself is in disarray? What happens when the old models of predictability and assurances no longer apply? When the weather is no longer normal? When the temperatures become extreme? When the company of a familiar species disappears? When a forest starts to mean fires, and not cool comfort, safe seclusion and green protection? When the model we have of the outside world does not fit the reality of what is actually occurring then we experience the disconnection as anxiety. This manifests internally as “climate grief, eco-anxiety, environmental melancholia, pre-traumatic stress syndrome”, and a host of other psychological and physiological symptoms.

The inside and the outside are intimately interconnected. It’s how we survive. Change the outside, and the inside struggles to make a new and secure model of predictability. We adjust. But what if the structure of the outside keeps changing faster and more frequently than our ability to invent and adjust to new models? Then our sense of security is exacerbated and we experience increased symptoms of anxiety. This, however presents another dilemma because the world is such a big and diverse place that we don’t all experience the same threats to our security.

Slightly more than half of humanity now lives in cities. Each individual’s model of reality is different from the model of those who live in rural settings. Only a few people live in Greenland or Antarctica, so only they notice that the glaciers are melting. The Arctic is sparsely populated, so only the local inhabitants are directly aware that it is warming extremely fast—indeed, 4 times faster than the rest of the planet. Almost everyone is experiencing some manifestation of climate change—flooding, heat, forest fires, unusual diseases, droughts, extreme storms, rising sea levels—but few if any people experience these diverse symptoms all at once. Only science unifies all these different events into a single explanation that is clear, unequivocal and indisputable.

Although everyone lives in a world of technology, not everyone trusts, understands or even appreciates the assessment of scientific authority that is measuring the unfolding of a global, multidimensional, environmental crisis. Some people, from the temporary safety of their religion, their ideology, their unreliable news sources, their insulated luxury, their naive indifference or their abject ignorance, even doubt the empirical evidence. This represents a profound disconnection of the inside model of the world from the outside reality, with consequences that will probably be ominous.

Ray Grigg for Sierra Quadra