Because of the recent brouhaha regarding Pluto's non-planetary status, an editorial at the Washington Post posits the question why defintions are so important.
Some choice exerpts:
Definitions and categories are the handles by which we grasp the world. If we change the handles, we change how we see the world.
The reason people care so much about one definition rather than another is because definitions are markers for group identity, said Barbara King, a biological anthropologist at the College of William and Mary who studies social behavior in primates. Wanting to see the world a particular way is an extension of our innate tendency to form groups, coalitions and tribes.
The moral lesson is: be more careful with your definitions.