Postman is trying to show the distinction between education and disaster.  This disaster is the increasing impact and dependency on technology which can be debatably hindering our learning, thinking,and comprending processes.  Entertainment is expected; we laugh although we may not know why were laughing just because we are used to being amused.  It is the goal of television shows.  But with this our thinking has stopped as the accessibility to media consumes our lives.  For instance, rather than trying to figure out something, like the meaning of epistemology based on contex clues, we can quickly google search the answer.