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title: The Law of Diminishing Returns
created: 2025-11-09T08:52:54
modified: 2025-11-12T18:04:14
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![](https://images.prismic.io/sketchplanations/6b64ffe3-b891-4838-989c-a5e0f6d66bce_SP+642+-+Law+of+diminishing+returns+-+revised.png?auto=format%2Ccompress&fit=max&w=640)

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* 邊際效用（Marginal Utility）：針對「消費者」，例如：多喝一杯水是否更滿足。
* 邊際報酬（Marginal Returns）：針對「生產者」，例如：多聘一個工人產量會提升多少。

> 兩者都會有「遞減法則」：投入或消費到一定程度後，每單位增加帶來的效用或產出會逐漸減少。

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一個和尚挑水喝，兩個和尚抬水喝，三個和尚沒水喝

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一斗米養個恩人，一石米養個仇人

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渴時一滴如甘露，醉後添杯不如無

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「朝四暮三」— 莊子《齊物論》

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「水和鑽石的悖論」 by 經濟學家 Adam Smith

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Example: The first time someone uses a drug, it often produces intense pleasure. But with repeated use, each additional dose provides less euphoria than the one before. Over time, the same amount of the drug may only bring a person back to their normal baseline, while between doses they feel worse than before. Because each use gives progressively smaller rewards, people often take more and more of the drug to chase the initial high—this cycle of diminishing returns can lead to [addiction](addiction-is-not-about-pleasure-its-about-escape.md).