I find it useful to sort what a mind does into three realms: the physical, the emotional, and the intellectual. The split is old. Plato divided the soul into appetite, spirit, and reason, and held that reason should rule. Educational psychology arrived at nearly the same three. It calls them the psychomotor (movement), affective (feeling), and cognitive (thinking) domains.
My question is not Plato’s. I do not ask which realm should rule. I ask where a person’s effort actually goes.
My intuition is that each realm carries its own scale of desire, running from discomfort to comfort. We seek a realm that pays us in comfort, and we avoid one that costs us. Effort is limited, so without noticing we run a cost-benefit analysis and spend where the return feels best. That part is more than intuition. In 2013 Robert Kurzban and colleagues argued the feeling of effort is itself the output of such a calculation. A task feels hard when something else would pay better.
People differ in what pays. Psychologists measure the need for cognition, which is how much a person seeks out and enjoys hard thinking. They also measure the need for affect, which is how much a person approaches or avoids strong feelings. I know of no measure as well known for the physical realm. Still, anyone who has met both an athlete and a bookworm knows that difference is real.
Put the three together and the ranking starts to look like temperament. Mine runs intellectual, physical, emotional. Someone else’s runs the other way, and a room built for them can feel foreign to me. Neither order is a flaw. It is a budget, set by what has paid before.
Some call the spiritual a fourth realm. I think it is the three at once. Awe, its best-studied form, joins a sense of vastness, a feeling, and a mind remaking its frame. Spirituality’s brain circuit also serves fear and pain. The evidence points that way, short of proof.
One caution. The split tempts people to tie it to something solid. William Sheldon tied three temperaments to three body shapes, and his claims have since been dismissed as quackery. The realms are a way to sort activity, not body types.
The use I get from this is modest. When someone’s choices puzzle me, I ask which realm pays them. It is usually not mine.