Murphy's lawyoudaoicibaDictYouDict[Murphy's law 词源字典]
1958, used of various pessimistic aphorisms. If there ever was a real Murphy his identity is lost to history. Said to be military originally, and probably pre-dates the earliest printed example (the 1958 citation calls it "an old military maxim").[Murphy's law etymology, Murphy's law origin, 英语词源]