One of the things I’ve noticed in Einstein’s writings is that he had a remarkable self-confidence and sense of certainty. Compare this with Darwin who, when he initially conceived of natural selection, annotated the note describing it with “I think” and proceeded to spend years gathering evidence before mentioning it to anyone. Perhaps the comparison isn’t fair because Darwin knew his idea would be highly controversial but, if it is, I think this might suggest that there is no single correct stance on confidence versus humility.
I’ve noticed in my programming that when I make errors that prevent me from reaching a solution or lead to a cumbersome design my natural tendency is to become more conservative with my ideas, thinking that it might have been arrogance that caused the error. But, if I feel like I understand the error well, I force myself to remain bold in the knowledge that my continued boldness will be manifest in a completely different way with my new knowledge and I will be successful much sooner than had I become timid. I don’t know who said this, but it is a quote I like: the solution to bad decisions is not to stop making decisions; it’s to make better decisions.