"The information that was contained in a cathedral was based upon a common culture - a common Christian culture - and the elements were chosen for a common symbolic meaning. Someone who knew everything that was represented in a cathedral had a sort of encyclopedia - you can indeed call it that - but it was a selective encyclopedia, like encyclopedias back when they were books and the people writing them were supposed to be specialists in their field. I think today the problem is that people don't know how to choose between different kinds of information."