# Convention

> 【EN】The central philosophical task posed by conventions is to analyze what they are and how they differ from mere regularities of action and cognition. Subsidiary questions include: How do conventions arise? How are they sustained? How do we select between alternative conventions? Why should one conform to convention? What social good, if any, do conventions serve? How does convention relate to such notions as rule, norm, custom, practice, institution, and social contract? Apart from its intrinsic interest, convention is important because philosophers frequently invoke it when discussing other topics. A favorite philosophical gambit is to argue that, perhaps despite appearances to the contrary, some phenomenon ultimately results from convention. Notable candidates include: property, government, justice, law, morality, linguistic meaning, necessity, ontology, mathematics, and logic. 【中】约定提出的中心哲学任务是分析约定究竟是什么，以及它与单纯的行为和认知规律有何不同。衍生问题包括它如何产生、如何维持、如何选择、为何要遵守，以及它与规则、规范、习俗、制度和社会契约的关系。词条讨论社会约定、约定主义、约定真理，并比较休谟与刘易斯的分析、替代约定的可能、约定是二分还是程度问题，以及应采用哪种均衡概念。

- ID: m13181
- Category: culture
- Domain: 哲学

## Definition

约定是被群体共同遵循的行为或认知的规律性，其特殊性在于：它是解决重复性协调问题的任意性方案，因他人也遵守它而得以维持，并由此区别于单纯的行为规律、规则、规范与制度。 脚手架作用：- 协调分析：识别靠他人遵守才维系的规则，找出可替换均衡。 - 变革评估：估算改变约定需要多少人同步行动。 - 规范区分：区分任意约定与道德规范，别把习俗当义务。

## How it works

约定靠预期的相互依赖维持：在有多个等价解的协调问题中，每个人选 A 是因为预期他人也选 A。刘易斯把它刻画为协调博弈的均衡加上关于该均衡的共同知识；正因解是任意的，约定才区别于由独立理由支撑的规律，也才有惯性与路径依赖。

## Practice

1) 判断该实践是否解决协调问题，是否存在等价的替代方案（任意性检验）。2) 检查维持它的是共同预期还是外部制裁。3) 区分约定与道德规范、法律规定。4) 若约定造成低效，说明为何难以单方面改变。

## Use

- 协调分析：识别靠他人遵守才维系的规则，找出可替换均衡。 - 变革评估：估算改变约定需要多少人同步行动。 - 规范区分：区分任意约定与道德规范，别把习俗当义务。

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