A farmer noticed that his chickens were sick, and called in a biologist, a chemist, and a physicist¹ to help diagnose the problem. The biologist observed the chickens, concluding, "I can tell you there's something wrong with your chickens, but I don't know what's causing it." The chemist took fluid samples from the chickens back to his lab, and returned saying, "I can tell you what's infecting your chickens, but I don't know how they got it." Meanwhile, the physicist had been sitting on the floor, scribbling² madly on several notebooks worth of paper. Suddenly, he jumped up, exclaiming, "I have the answer, but it only works for spherical³ chickens in a vacuum."

有个农民注意到他的鸡病了，于是请来一位生物学家，一位化学家，以及一位物理学家来帮忙诊断。这位生物学家观察了鸡下了结论：“我知道你的鸡出了什么问题，但是我不知道是什么导致的。”化学家从鸡身上取了液体样本回实验室，返回后解释：“我知道是什么使鸡感染，但是不知道是怎么感染到。”与此同时，物理学家坐在地上，在笔记上胡乱记下对论文有价值的材料。突然，他跳了起来，大叫：“我有答案了，但这只针对真空中的球形鸡有用。