A novice was trying to fix a broken Lisp machine by turning the power off and on. Knight, seeing what the student was doing, spoke sternly: "You cannot fix a machine by just power-cycling it with no understanding of what is going wrong." Knight turned the machine off and on. The machine worked.
See the JargonFile at http://www.catb.org/~esr/jargon/html/koans.html
I thought the story stated the novice was turning it on and off.