There seem to be two meanings to the word “confident” in English. The first is the idea of confidence as a generic motivational aspect; we should learn to put aside our inhibitions and then we can tackle a problem with confidence. Call this motivational confidence.
The second is the feeling that you have been able to calibrate your actions against experience. this is the kind of confidence where you know, and know you know, when you have got something correct. Perhaps we can call this calibrational confidence.
It seems that we confuse the two fairly readily. When I say that I am not a confident singer (which is true), I am saying that I cannot calibrate my attempts at singing against the world. I don’t feel that I am singing wrongly, but I wouldn’t bet any amount that I am not awful. When I try to correct this, I am frequently told that I should be more confident; this is clearly a references to motivational confidence, as this can be summoned by willpower, whereas calibrational confidence can only be gained by skill and knowledge. However hard I might say that I am going to sing out with confidence, if I am unable to calibrate my efforts then I am not going to improve—by contrast, I’ll be like one of those godawful people at karaoke who belt out a song with great will but little skill.
I wonder why these two contrasting concepts have the same word? And, why many people conflate the two, and believe that the second will follow automatically from the exercise of the first? Clearly they are not entirely unrelated; but the link is fairly slim.