the.com/safety margin
The gap between fine and finally not fine.
means The buffer deliberately built between what you expect to happen and the point where things actually go wrong.
from Not an ancient word but an engineering compound: 'margin' comes from Latin margo, 'edge or border' — the same root as the margin of a page, the blank edge left so the real text doesn't run off the paper. 'Safety' traces back to Latin salvus, 'unharmed, whole.' Engineers bolted the two together as 'margin of safety' in structural and mechanical design, meaning the edge of blank space you leave between the load a thing must bear and the load that would actually break it. The phrase later wandered out of blueprints into ordinary speech, keeping its original shape: a border of unused room between you and the edge.
- engineering default
- bridges built to hold triple the expected load
- financial version
- Buffett calls it buying a dollar for fifty cents
- paradox
- the better it works, the less anyone notices it
- common failure
- people shrink it the moment nothing has gone wrong yet