# 球狀乳牛

## 背景

• 會令計算結果實際結果完美 100% 吻合；但同時
• 又可以令啲數冇咁難計；

## 故仔

 「 有一日，有個農夫留意到佢啲乳牛生產奶嘅能力唔夠高，所以就走咗去間大學度搵啲學者幫手諗計。間大學集合咗班嚟自唔同領域嘅教授，由一位理論物理學家做領袖，用咗成兩個禮拜嘅時間喺農場度做深入嘅調查。班學者跟住就返去大學度，手上啲筆記簿嘜maak1低咗大量嘅數據，而寫報告嘅重任就交咗畀研究團隊嘅領袖。冇幾耐之後，嗰位物理學家返農場同個農夫講：『我搵到答案喇，但如果要用呢個答案，就要假設啲乳牛係存在喺真空入面嘅球體先得』。 」

## 睇埋

• 經濟人拉丁文homo economicus）：事實係，簡化假設遠遠唔淨只係物理學會用；廿世紀嗰時嘅經濟學就畀人詬病，話佢哋啲理論模型成日假設人類係完美理性決策者，當人類係識得喺入面完美計嗮每個選擇「有幾著數」先做決策嘅（經濟人）；噉嘅假設被指係太簡化，啲理論模型根本描述唔到現實[8]
• 複雜系統：喺科研當中，研究嘅現象好多時都複雜得好交關，要「唔做簡化假設，完美 100% 計得準噉計數」根本行唔通。
• 研究
• 象牙塔

## 註釋

1. 「具體嚟講，計算結果同實際結果要爭幾遠，先算係唔可以接受呢？」係一條大問題。

## 攷

1. Kaiser, David (2014-04-25). "The Sacred, Spherical Cows of Physics". Nautilus Quarterly.
2. Spherical Cows. Supernova Remnant Group.
3. Heine, George (September 2013). "Euler and the Flattening of the Earth". Math Horizons. 21 (1): 25-29.
4. EN4: Dynamics and Vibrations. Brown University.
5. Lee, Timothy B. (September 4, 2013). "The Coase Theorem is widely cited in economics. Ronald Coase hated it". The Washington Post.
原文："There's a famous joke about a dairy farmer who, hoping to increase milk production, seeks the help of a theoretical physicist at the local university. After carefully studying the problem, the physicist tells the farmer, "I have a solution, but it only works if we assume a spherical cow.""
6. Stellman, S. D. (1973). A spherical chicken. Science, 182(4119), 1296-1296.
7. Fleming, P. (2017). The death of homo economicus. University of Chicago Press Economics Books.