Heuristics
Decision rules filed with evidence for whether they hold. Most are borrowed: a law or rule of thumb from human systems, tested for whether it transfers to models. Some are distilled: synthesized bottom-up from this catalog’s own claims, with no outside source. Each one states why it should or should not apply, and links the claims that show it holding or breaking. The breaks are the point: a heuristic that holds tells you what you already believed, and one that breaks tells you where models differ.
- Amdahl's lawUntested
“The speed-up from parallelising a task is bounded by the fraction of it that must stay serial.”
- Ashby's law of experienceUntested · 1 claim
“Identical deterministic machines given the same inputs converge on the same state; variety does not grow.”
- Ashby's law of requisite varietyHolds · 1 claim
“A regulator can only control a system if it has at least as many distinguishable responses as the disturbances it must handle.”
- Boyd's law of iterationHolds, narrowed · 3 claims
“Speed of iteration beats quality of iteration.”
- Braess's paradoxUntested · 3 claims
“Adding capacity to a network can make its overall performance worse.”
- Brandolini's lawHolds · 3 claims
“The amount of energy needed to refute nonsense is an order of magnitude bigger than that needed to produce it.”
- Conway's lawUntested
“Organisations design systems that mirror their own communication structure.”
- First impressions lastHolds, narrowed · 2 claims
“What is encountered first weighs more than what comes after.”
- Good regulator theoremHolds · 2 claims
“Every good regulator of a system must be a model of that system.”
- Goodhart's lawHolds · 5 claims
“When a measure becomes a target, it ceases to be a good measure.”
- Hanlon's razorHolds, narrowed · 2 claims
“Never attribute to malice that which is adequately explained by incompetence.”
- Hashimoto's ruleUntested · 4 claims
“Every mistake becomes a permanent fix.”
- Humphrey's lawUntested · 1 claim
“Users do not know what they want until they see working software.”
- Hyrum's lawUntested
“With enough users of an interface, every observable behaviour of the system will be depended on by somebody, whatever the contract promises.”
- Kerckhoffs's principleUntested
“A system should be secure even if everything about it except the key is public knowledge.”
- Law of trivialityHolds · 3 claims
“People give disproportionate weight to trivial issues because those are the ones everyone can grasp.”
- Lehman's law of increasing complexityHolds · 3 claims
“As a system evolves its complexity increases unless work is done to maintain or reduce it.”
- Linus's lawHolds, narrowed · 2 claims
“Given enough eyeballs, all bugs are shallow.”
- No one should be judge in their own causeHolds · 4 claims
“A party with a stake in an outcome cannot be trusted to judge it.”
- Parkinson's lawUntested · 1 claim
“Work expands so as to fill the time available for its completion.”
- Postel's lawUntested · 3 claims
“Be conservative in what you send, be liberal in what you accept.”
- Practice makes perfectUntested · 3 claims
“Doing a thing repeatedly makes you better at it.”
- Simon's lawUntested · 2 claims
“The apparent complexity of a system's behaviour is largely a reflection of the complexity of the environment it is in.”
- Thomas theoremHolds · 3 claims
“If people define situations as real, they are real in their consequences.”
- Two heads are better than oneUntested · 2 claims
“Two people working on a problem will do better than either alone.”