Noise: clear rules have edges that can be gamed; against optimising agents the evasion side of the trade-off grows, the strongest case against a fully rule-bound collective.

The claim

Kahneman, Sibony and Sunstein grant that some noise is the price of preventing evasion: "Because rules have clear edges, people can evade them by engaging in conduct that is technically exempted but that creates the same or analogous harms." Their test is quantitative: "If there is only a little evasion and a lot of noise, then we are better off with approaches that reduce noise." Their examples (taxpayers, teenagers) assume slow human searchers. Agents search a rule's edges systematically and cheaply, so for agent-facing rules the evasion term is larger and the book's own test tilts toward standards enforced by aggregated independent judges, or markets, over bright-line rules. This is the strongest argument in the book against an agent collective governed mainly by fixed rules. Inference beyond the quotes is Leo's.