If a problem has no solution, it may not be a problem, but a fact, not to be solved, but to be coped with over time.

Shimon Peres (1923-2016) Polish-Israeli politician, statesman
(Attributed)

Widely attributed to Peres in different sources. Quoted in the Wall Street Journal (7 Feb 2001). Donald Rumsfeld says that Peres made the observation to him.