best of all possible worlds, n.

The Best of all possible worlds (n.) does ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠not exist, for good and happiness have no clear definition and nothing is for the best.