《公孙龙子·迹府》
公孙龙说： 先生的话未免荒唐了，我的学问，就在于以白马异于马这个学术原则，要我放弃它，我便没有什么可教的了。
公孙龙曰： 先生之言悖。龙之学，以白马为非马者也。
Gongsun Long said: Sir, your words are somewhat absurd. My teachings lie in this academic principle that a white horse is different from a horse. If I were to abandon it, I would have nothing left to teach.