brightness vs pessimism

brightness

noun
  • Intelligence, cleverness. 

  • The quality of being bright. 

  • The perceived luminance of an object. 

pessimism

noun
  • A general belief that bad things will happen. 

  • The condition of being pessimal. 

  • The doctrine that this world is the worst of all possible worlds. 

How often have the words brightness and pessimism occurred in a corpus of books? (source: Google Ngram Viewer )