Common sense叫常識。You have no common sense!(你一點常識也沒有！)被人這樣說一定很不是味兒。見工面試時，lack of common sense也是致命傷。有人這樣形容common sense：
      Common sense is beliefs or propositions that most people consider prudent and of sound judgment, without reliance on esoteric knowledge or study or research, but based upon what they see as knowledge held by people "in common".
      Esoteric解秘傳的、難理解的。根據這個定義：“Common sense是大部分人覺得謹慎和判斷正確的信念或命題，這些認知不用靠難理解的知識或研究，而是以大家分享的知識為基礎。”
      換句話說，common sense是大部分人已經有的知識或經驗，或大家都覺得應該知道的知識。有common sense說話就make sense，沒有common sense就會被認為無知。雖然如此，法國哲學家Fran?茳ois-      Marie Arouet卻指出︰"Common sense is not so common."(常識並不普遍。)

      自欺欺人想法
      被捧得那麼高，但common sense真是那麼有價值嗎？是否沒有common sense就真的等於無知？學者Duncan Watts在Everything is Obvious: Once You Know the Answer一書中提出理論，認為common sense只是集體自欺欺人的想法。他用名畫Mona Lisa作為例子：
      "We claim to be saying that the Mona Lisa is the most famous painting in the world because it has attributes(特質) X, Y and Z. But really what we're saying is that the Mona Lisa is famous       because it's more like the Mona Lisa than anything else."
      換言之，我們像是被困於一個四面都是鏡子的房間內。
      We think the Mona Lisa is famous because of its traits(特質), but we think those traits are significant only because they belong to the Mona Lisa, which we know to be famous.
      (《蒙娜麗莎》出名是因為它有某些特質，但我們覺得那些特質特別，只是因為我們知道那些是《蒙娜麗莎》的特質，而我們也知道《蒙娜麗莎》出名。)

      根據Duncan Watts的說法︰
      Common sense is a kind of bespoke make-believe, and we can no more use it to scientifically explain the workings of the social world than we can use a hammer to understand mollusks.
      (常識是一種宣之於口的幻想，用它來解釋社會的運作，就像用一柄鎚子去研究軟體動物一樣不濟事。)
      我們製造common sense，只是為了替自己製造凡事都可解釋的假象：
      We can skip from day to day and observation to observation, perpetually(不斷地) replacing the chaos of reality(紛亂的現實) with the soothing fiction(舒服的虛構) of our explanations.

      糾正整體思維
      Duncan Watts在書中挑戰的，不只是common sense，而是我們整體思考的方法。我們對事事都像有很完備的解釋，像是很清楚這世界的運作，然後用所得的結論去計劃將來，結果好可能是差之毫釐，謬之千里。只有明白how and when common sense fails，我們才能糾正這個錯誤。