6.3.1 Feynman’s Blackboard
= Relativity + Quantum Mechanics
6.3.2 Quantum Mechanics | 量子力學
When physicist Feynman was a student,
there were two versions of Quantum Mechanics.
They described the same thing
but in different mathematical languages.
One version was Heisenberg’s Matrix Mechanics (矩陣力學) , using matrices. Another was Schrodinger’s Wave Mechanics (波動力學), using differential equations.
Feynman could understand neither of them.
So he spent 8 years to create
his own version of quantum mechancis
in order to understand quantum mechanics .
Feynman’s version of quantum mechanics is now called
Feynman path-intergral. (路徑積分)
After Feynman’s death,  people found that Feynman had written some words on the left-hand top corner of his blackboard:
“What I cannot create, I do not understand.”
 Dyson, Disturbing the Universe (1979)
 “I’d hate to die twice. It’s so boring.” — Feynman’s last words