Word for “so confident that cannot see the truth”
Example setting: You are discussing a certain topic/problem with a math professor who is good at that certain topic/field. On this occasion he is wrong but cannot see the point because he is too confident of himself. My choice is overconfident; is there a better single word?
This might possibly have negative connotation where you don't mean to imply such, but the word that comes to mind is obstinate.
From Merriam-Webster
Obstinate: refusing to change your behavior or your ideas
I might even say "He was confidently obstinate" to clarify the source of the obstinance, but I believe over-confidence is the default assumption in these cases.
What about hubris? It denotes a similar kind of overconfidence.
presumptuous
too confident especially in a way that is rude : done or made without permission, right, or good reason
usage:
A class of presumptuous men, whom age has not made cautious, nor adversity wise. --Buckminster
Your professor seems to have superiority complex
- an inflated estimate of one's own merit, usually manifested in arrogance (Collins via TFD)
You could also call him self-opinionated
Having an arrogantly high regard for oneself or one’s own opinions (Oxford)
Or even conceited
Excessively proud of oneself; vain (Oxford)