Nobody knows anything. I deal with people in all walks of life, some of whom should have some idea of what they're doing. And they're all clueless. It's astonishing that any bridges stay up, or that planes don't constantly plummet from the sky. It's heartening, in a strange way.

This quote means that no one really knows what they are doing in life. It doesn’t matter where you go or what kind of person you meet, the majority of the people don’t have a clue as to how to do things. Despite this, it is impressive that structures such as bridges and planes are able to function without falling apart. In some way, it is comforting that things can still work even though nobody really knows what they are doing.