I have to push back regularly against my own sense that mental fatigue is a brain issue. Mind-body dualism has a lot to answer for, and I think it (mis)informs a lot of how we humans see ourselves in relation to the natural world.
Our brains are not separate from our bodies. The same blood makes its ways around the whole system. Brains are squidgy lumps of biological material. They need energy, oxygen, and do better if we don’t hit them with stuff. Mental energy, is energy.
Getting mentally tired isn’t some kind of special brain event. It isn’t about not trying hard enough and it cannot be overcome simply by making more effort. Like the other parts of our bodies, brains need rest. They need sleep, and unstressful downtime. Our brains suffer if we are dehydrated, or too hot, or experiencing too much stress in our bodies.
However, the idea of the mind as separate from the body is a pervasive one. It can be so easy to absorb ideas about the human mind being separate from nature as a whole that we might not even notice what we’re doing to ourselves.
I have to remind myself that if my concentration is poor, this may be because I’m tired, or need food, or I require a break from things. How well I can think is a facet of how well my body is doing overall. I don’t think well in unbearably hot weather. Being in a lot of pain really compromises my brain.
The big one for me is remembering that energy is not an abstract idea. Mental energy is not magically different from other energy. My brain requires food just as much as the rest of my body does. I grew up subject to a lot of misinformation about calorie controlled diets. As though intense mental activity required no nourishment. We’re getting better now at recognising that brains need fats in the diet to function well, but too many of us were taught that fats are bad and to be shunned.
One of the ways we can approach nature as Druids is to explore the ways in which we are natural beings, and the ways in which human ideas have distorted our relationship with our own natural selves. Brains aren’t magically separate from bodies. Minds are not abstract things and do not exist in a different dimension to our physical selves. Consciousness may remain a bit of a mystery, but is only viable when we have enough oxygen in the first place.