• Act rationally
  For a given set of inputs, tries to generate an appropriate output that is not necessarily correct but gets the job done. Rational and sufficient ("satisficing" methods, not "optimal").

Rational behavior: doing the "right thing"

• The right thing: that which is expected to maximize goal achievement, given the available information
  
• Doesn't necessarily involve thinking, e.g., blinking
  
• Thinking can be in the service of rational action
  
• Entirely dependent on goals!
  
• Irrational is not the same thing as insane, irrationality is suboptimal action
  
• Rational is not the same thing as successful

Our focus here: rational agents

• Systems which make the best possible decisions given goals, evidence, and constraints
  
• In the real world, there is usually lots of uncertainty and lots of complexity
  
• Usually, we're just approximating rationality

"Computational rationality" is a better title for this book.