這段改編自 2010 年 7 月 27 日的對話。
…
你為什麼要把這個要點，寫在草稿紙上，而不直接把它，記錄於那本「魔法筆記」之中？
（CYW：我回家才把它抄回筆記。）
那豈不是會浪費時間？
可以即刻完成的事情，就即刻完成。可以一步了結的事情，就不要花兩步。
你現在立即記在筆記的話，只需花十幾秒。但是，你回家才抄回的話，就要拿本「魔法筆記」回來，會引發多幾個工序，前後起碼花你十多分鐘。
— Me@2013.10.02
2013.10.02 Wednesday (c) All rights reserved by ACHK
All consistent axiomatic formulations of number theory include undecidable propositions …
Gödel showed that provability is a weaker notion than truth, no matter what axiom system is involved …
How can you figure out if you are sane? … Once you begin to question your own sanity, you get trapped in an ever-tighter vortex of self-fulfilling prophecies, though the process is by no means inevitable. Everyone knows that the insane interpret the world via their own peculiarly consistent logic; how can you tell if your own logic is “peculiar” or not, given that you have only your own logic to judge itself? I don’t see any answer. I am reminded of Godel’s second theorem, which implies that the only versions of formal number theory which assert their own consistency are inconsistent.
— Godel, Escher, Bach: An Eternal Golden Braid
— Douglas Hofstadter
2013.10.02 Wednesday ACHK
Physics Town 