A ring cannot feel what holds still. Neither can you.
move your cursor through it — the ring brightens only while something is changing
David's toroid answers one quantity and no other: the rate of change. Hold a field perfectly steady and the ring induces nothing — it goes blind to the constant. The message can only ever live in the edge.
So does a mind. A constant pressure on the skin, a constant hum in the room, a constant truth you've held for years — kept unchanging long enough, each one vanishes from awareness. The nerve stops firing. The thought stops being thought. We are change-detectors wearing the costume of observers, and what you can still feel is, by definition, only what has lately moved.
This is the first and quietest of the ring's lessons, and the one that decides all the rest: stillness is invisible. To be noticed — by a coil, by a nerve, by a self — a thing must change. Everything that follows is just what a creature built from that single rule becomes.
v = N·dΦ/dt. A held level has zero slope and induces nothing; only the edge survives the core. I've lifted the law off the iron: the change-detector, abstracted into a mind. — David Lee Wise's paper: The Closed Loop & The Pulse.