Fable
Only seeing that the clock has stopped, without knowing which gear jammed first
There was a great bell in the square of Silver Bell Town. It announced the time every morning: shops opened, schools began classes, docks released boats, and the whole town arranged its rhythm around the bell. The townspeople did not understand the bell; they only knew that when it rang, everything was normal.
One morning, the great bell did not ring. The mayor immediately called the clock repairman. The repairman climbed the bell tower and saw the hands stopped at 5:47. The mayor asked: Where is it broken? The repairman said: Right now I only know it has stopped, not why it stopped.
The mayor was very dissatisfied. He said, isn’t it obvious that the clock has stopped? Just fix it. The clock repairer shook his head: if I only reset the hands, it may stop again this afternoon; if I randomly replace gears, I may replace good parts. What we see is the result, not the cause.
In the past, clock repair in Silver Bell Town relied on experience. Listen to the sound, feel the temperature, guess the wear. When the old master was there, most clocks could be repaired; when the old master was ill, newcomers could only remove one part, try one part, and put it back. Every repair was like groping inside a black box.
Later, the new clockmaker added three things to the great clock. The first was small notches, leaving a record each time a gear turned one revolution; the second was fine copper wire, able to show which section of transmission had slowed; the third was oil lamp marks, able to reveal where friction suddenly increased.
At first the townspeople thought these things were superfluous. They only cared whether the bell rang; who cared how many times the gears turned? That was until the next time the great bell ran half a quarter-hour slow. The clockmaker did not dismantle the whole clock; he only looked at the records and found that it was not the main gear that had failed, but a small bearing on the third level that had stiffened after the rain, causing everything after it to slow down.
This time, fixing the clock took only half a shichen. More importantly, the clockmaker could also tell the mayor: if this bearing is not replaced, it will stop again in three days; if oil is added tonight, it can last until the market closes; if the problem is to be solved completely, the moisture-proof cover needs to be replaced.
Only then did the mayor understand that recording the gears was not to satisfy curiosity, but so that when the system failed, people would no longer see only the final silence. Only by seeing the process can you talk about analysis, stopping the bleeding, recovery and improvement. Later, the great clock of Silver Bell Town still broke, but no one ever treated "the clock stopped" as a complete answer again. The truly valuable questions became: which step slowed down first? Which component has the greatest impact? Can we see it in advance next time?