sorter/sorted

The other four concern an object losing its edge. This one concerns the sorting subject, and the boundary between the sorter and its tool. When a device works well it disappears; you see through it to the task, which is what ready-to-hand describes and what infrastructure repeats at institutional scale. The moment it stutters it snaps back into view. The transition is measurable — a smoothly-used tool produces pink noise at the hand–tool interface, and when the tool is disrupted the pink noise collapses. The boundary is not fixed. It is continuously enacted, which is also the interface's argument, and it can be read off the noise.