There are certainly many ways to come to personal self-confidence and peace of mind. One way may be faith, another (I guess my way) is to embrace uncertainty. That is to say: “hey, I don’t know what’s going to happen, but whatever happens, I’ll give my best”.
This attitude seems related to the scientific method where a theory can never be proved. A scientific or philosophical theory is just a useful working concept until proven wrong. Then a better theory has to be developed. In this method there is no right, no absolute truth, only a constant struggle to improve.
From this concept of embracing and working with uncertainty, indeed never accepting that some theory might be the absolute truth, comes a great deal of self-confidence because you haven’t that much to lose anymore, because you always knew you couldn’t have had discovered the absolute truth anyway. And while there might be a few so-called scientist that have forgotten this, I think that the great majority take this way of thinking for granted. Indeed, they take it so much for granted that they often fail to mention it explicitly to the public.
The result of all this, I think, is that many people that don’t take uncertainty for granted but are looking for some kind of genuine truth will think that scientists are overconfident and they might feel that scientists think they can explain everything while actually the exact opposite is the case.
All in all a quite unfortunate situation. So what is there to do? Scientists on one hand should get better at communicating with the general public, the public on the other hand needs to get a better understanding of science and the scientific method.