这周我们要讨论的是“事后批评”。有些人在原则上避免事后批评自己。就像艾里沙爵士在《权力的游戏》里说的:“领导力就是被每个有嘴巴的聪明小傻瓜事后批评。但是，如果一个领导者开始事后批评自己，那就完了。这是结束。"

但即使是领导人，有时也会做出轻率的判断和无知的选择。如果布什和他的伙伴们在决定入侵伊拉克的问题上稍微反省一下自己的话，我们的日子会过得更好，这一点并不难反驳。当然，谁又能说他们第二次会做得更好呢。此外，如果你开始走这条路，你可能很快就会怀疑自己的第二次猜测。谁知道结果会怎样。

In any event, I’m not suggesting that you should never stick to your beliefs and decisions. But that doesn’t mean you should always stick to them either. It’s not an all or nothing thing. Wouldn't it be great if there were some nice, neat formula, for deciding when it’s a good thing to second-guess yourself? I doubt there could be such a formula, but of course maybe I should reconsider those doubts. (Ha!)

Take the following example. Suppose you catch a glimpse of a person in the distance at a restaurant and think might be me. Suppose you're pretty sure, but not 100 percent certain. Maybe you're 70 percent sure, just to give it a number. Later on I tell you that it wasn’t me that you saw. Should you just stick to your original belief? Isn’t it reasonable for you to reduce your confidence -- maybe all the way down to zero -- that it was me you actually saw?

Of course, for all you know I could be lying to you. Maybe you saw me at some very intimate dinner, staring longingly into the eyes of a very attractive woman, who didn't look all that much like my wife, so I'm just trying to distract you. My point is that sometimes our confidence in our beliefs can be less than complete. When we get more evidence, we should be willing to change our degree of belief -- up or down – in light of new evidence. If I told you, for example, that it really was me that you saw, wouldn’t your confidence shoot all the way up to 100 percent?

But now we’re not really talking about second-guessing ourselves, we’re talking about reconsidering old beliefs in light of new evidence pro or con. That's just what rational people do. What rational people don’t do and shouldn't do is go around second-guessing themselves on the basis of no real evidence whatsoever. Once the evidence is in, and you’ve made up your mind, stick to your guns. Don’t go changing your mind just because you think you might possibly be wrong.

But what if the belief that you might possibly be wrong is itself based on evidence -- not on evidence about whether I was in that restaurant or not… but on evidence about your own degree of reliability? For example, suppose you found out that you glasses had been tinkered with and that they now had a tendency to distort your vision -- a little far-fetched, maybe, but it makes the point. If you found out that your vision was being distorted, wouldn’t it make sense to change your degree of confidence in your belief that it was me you saw – even though you got no new direct evidence as to whether I was there or not?

Of course people are almost always subject to some sort of distorting influences when they draw conclusions or make decisions. If we let our confidence be undermined by that fact alone, it leads to self-doubt, skepticism, and inaction. Does that just paint a stubborn refusal to reconsider as an epistemic virtue? Or does praise a spineless indecisiveness as one? Tune in to find out what our guest, Sherri Roush (now at King's College London), author ofTracking Truth: Knowledge, Evidence, and Science,thinks about how best to go about evaluating our self-assements.