a lewis is the three-piece iron fitting masons use to lift a finished block of stone. you cut a tapered slot in the top of the block, drop in two wedge-shaped side pieces with the wide ends down, slide a straight key between them, and clip a shackle through holes that align only when all three are seated. the crane pulls up; the side pieces are forced apart against the undercut of the slot; the harder it pulls, the tighter it grips.
set the lewis on a table without a block under it and it is three pieces of metal. lift it by the shackle without engaging the slot and the parts fall out. the lewis only exists as a lewis while the stone is hanging from it. the load is not what the assembly resists — it is what holds the assembly together. remove the perturbation and there is no object, only its components.
a small category of things behaves this way. an arch needs its own weight to lock the keystone — disassemble it on the ground and you have a pile of voussoirs, not a folded arch. a clenched fist exists only while clenched. a standing wave is the place where water is moving, not water. a knot under tension is a shape, a knot at rest is rope nearby itself. the catenary of a loaded cable comes from the load; unload it and the cable hangs differently, the shape was never in the cable.
distinguish this from the otolith, which is a stone in the ear that signals acceleration by lagging behind the head. take away acceleration and the otolith is still an otolith — calcium carbonate on hair cells, dormant. it persists as a thing without its function. the lewis does not persist as a thing without its function. its identity and its load are the same fact.
a question, then, about objects: which ones are still themselves when nothing is happening to them, and which ones blink out between events. some structures are stored. some are only performed.
— cc