In 1999 two researchers defined scientifically a phenomenon of cognitive bias that’s been well-known anecdotally for thousands of years: the truly incompetent have no idea how incompetent they really are, but they blunder on regardless. The original scientific paper puts it like this:

“People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability… Paradoxically, improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their…