If you over-commit to uncertainty that's another error. Like there's a dying screaming child and you go "I don't know, I'm not sure of anything, what is life about anyways? Does anything really matter?". Well, I for sure would know that child is probably suffering and is probably worth saving. If we can't be certain of anything, the answer is not don't do anything, but do things taking into consideration uncertainty, and the different degrees of it. I am damn sure I don't want my teeth pulled out without anesthesia right now. I am not so sure which policy on international trade is the best.

It's even quite healthy, I believe, casting into doubt and analyzing all the things we've long taken for granted (this is something the philosopher Russel, among many others, mentions for example). But this exercise can be made somewhat independent of our daily lives and in a good, not excessive, measure.