And what we saw last time is that this was necessary to make things work, this part of it in particular.

上节课我们讲,这是对外做功的必要条件，特别是这个部分。

麻省理工公开课 - 热力学与动力学课程节选

But in fact, logically speaking at least, variability, although it's a requirement for unpredictability, doesn't guarantee unpredictability.

但实际上，至少在逻辑上讲，可变性虽然是不可预见性的必要条件，但是不可预见性却不是必然。

耶鲁公开课 - 死亡课程节选