Representation Languages

• One fundamental problem of designing a knowledge representation language is the fundamental tradeoff between (1) a language that is expressive enough to represent the important objects and relations in a problem domain, yet (2) allows for a tractable (i.e., efficient) means of reasoning and answering questions about implicit information in a reasonable amount of time
  
  
• Logic is a well-studied, general-purpose language for describing what's true and false in the world, along with mechanical procedures that can operate on sentences in the language to perform reasoning (i.e., to determine what "implicitly follows" from what is explicitly represented)