Bubi

   búbì    不必    bubi。“必”的反义词。墨家所使用的“不必”有以下一个意思：不一定，不是必然，不能确定。《经说上》说：“小故有之不必然。”必要条件是有了它不一定有某种结果。《经说上》说：“必不必也，是非必也。”一定不是必然，而只能是非必然。《经说上》说：“子在军，不必其死生；闻战，亦不必其生，前也不惧，今也惧。”儿子在部队上不能断定他的生死；但听到要作战了，也同样不能断定他的生死，但是先前不害怕可现在害怕了。

   "Not necessarily" is the antonym of "necessarily." In Mohist usage, "not necessarily" has the following meaning: not certain, not inevitable, and indeterminate. The Classic Commentary, Part I states: "Minor causes exist but are not necessarily so." A necessary condition is one where its presence does not necessarily result in a certain outcome. The Classic Commentary, Part I also says: "Necessity is not necessity, right and wrong are not necessity." What is certain is not inevitable, but rather non-inevitable. The Classic Commentary, Part I further states: "When a son is in the army, one cannot determine his life or death; upon hearing of war, one cannot determine his survival. Before, there was no fear; now, there is fear." A son in the army cannot have his life or death determined; upon hearing news of battle, one also cannot determine his survival, yet previously there was no fear, and now there is fear.