text: Formal logic needs to translate natural language 
  arguments into a formal language, like first-order logic, to 
  assess whether they are valid. In this example, the letter 
  "c" represents Carmen while the letters "M" and "T" stand 
  for "Mexican" and "teacher". The symbol "∧" has the 
  meaning of "and". 
  **Informal logic**
  
  When understood in a wide sense, logic 
  encompasses both formal and informal logic.[24] Informal logic uses non-formal criteria and standards to 
  analyze and assess the correctness of arguments. Its main focus is on everyday discourse.[25] Its 
  development was prompted by difficulties in applying the insights of formal logic to natural language 
  arguments.[26] In this regard, it considers problems that formal logic on its own is unable to address.[27] 
  Both provide criteria for assessing the correctness of arguments and distinguishing them from 
  fallacies.[28] 
  
  Many characterizations of informal logic have been suggested but there is no general agreement on its 
  precise definition.[29] The most literal approach sees the terms "formal" and "informal" as applying to the 
  language used to express arguments. On this view, informal logic studies arguments that are in informal 
  or natural language.[30] Formal logic can only examine them indirectly by translating them first into a 
  formal language while informal logic investigates them in their original form.[31] On this view, the 
  argument "Birds fly. Tweety is a bird. Therefore, Tweety flies." belongs to natural language and is 
  ; (2) 
  examined by informal logic. But the formal translation "(1) 
  " is studied by formal logic.[32] The study of natural language 
  arguments comes with various difficulties. For example, natural language expressions are often 
  ambiguous, vague, and context-dependent.[33] Another approach defines informal logic in a wide sense as 
  the normative study of the standards, criteria, and procedures of argumentation. In this sense, it includes 
  questions about the role of rationality, critical thinking, and the psychology of argumentation.[34] 
  
  ; (3) 