Many People Believe Strongly in the Notion That "Seeing Is

Many people believe strongly in the notion that "seeing is believing." However, research has shown that perceptual sets can cause people to "see" things that aren't really there, or not to see things that are. Why do you think people have so much confidence that what they see reflects reality? Is it simply because they are ignorant of the research, or do you think most people would continue to think that "seeing is believing" even if they were aware of perceptual sets? Defend your answer with reasoned arguments.