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