Knowledge isn't absolute

Every once in a while I meet somebody who believes that they know everything there is to know about a subject and that what they know is all that will ever be known about the subject. It is nice to be sure of yourself but come on! It is silly to think that what is known now is absolute truth and that this is all that will ever be known about a subject. We are constantly learning new things about old subjects and finding out that what we used to know about something isn't true. But no, these people are absolutely certain and cannot be swayed by logic.

What would lead somebody to this viewpoint? Why would anybody believe that what they know is absolute and no new knowledge is possible?

I have considered this question at length and have come to the conclusion that this is a form of wishful thinking. These people want to believe they know everything because they want to believe they are in control of their lives and there are no more surprises coming.

I like learning so the fact that no knowledge is absolute isn't a problem for me. But I think I can see why some people would want it otherwise because of a desire to be in control. I can sort of see it. But I wouldn't want to live in that world.