RIP Mr John Forbes Nash Jr

「Adam Smith需要修改。如果我們全都去追金髮美女，我們只會互相阻礙，而沒有一個人能得到她。然後我們會去追她的朋友們，她們定會冷待我們，因為沒人願意做替代品。但是如果我們都不去追金髮美女呢? 那我們就不會互相阻撓，也不會對其他的女孩無禮。這是我們唯一能全勝的方法。這是也是我們唯一全都能XX的方法。 Adam Smith說過最好的結果來自於團體裡的每一個人都只做對他個人有利的事，對吧？他是這樣說的，沒錯吧? 沒錯。但不完整。因為最好的結果是來自於，團體裡的每一個人都只做對自己和對整個團體都有利的事。」

-A Beautiful Mind (2001, AKA《美麗心靈》/《有你終生美麗》/《美麗境界》)裡對Nash equilibrium的演繹。

P.S. 據說電影放映後大獲好評，但教授們卻認為這個解釋有欠全面，所以寫信到New York Times說John Nash不可能做出一個如此粗疏的解說。但無論如何，電影如此生動地解說一個複雜的理論，還是值得尊敬。

Original quote from A Beautiful Mind: “Adam Smith needs revision. If we all go for the blonde, we block each other. Not a single one of us is gonna get her. So then we go for her friends, but they will all give us the cold shoulder because nobody likes to be second choice. Well, what if no one goes for the blonde? We don't get in each other's way, and we don't insult the other girls. That's the only way we win. That's the only way we all get laid. Adam Smith said the best result comes from everyone in the group doing what's best for himself, right? That's what he said, right? Right. Incomplete. Because the best result will come from everyone in the group doing what's best for himself and the group.”