每日原则：确保不可接受型事件(即毁灭性风险) 的概率为零

对于期望值的考量在不利因素极为糟糕的情况下也适用。例如，即使你患癌症的几率很低，当你有疑似症状的时候，做一下检查来确认还是很值得的。

Thinking about expected value also applies when the downside is terrible. For example, even if the probability of your having cancer is low, it might pay to get yourself tested when you have a symptom just to make sure.