calculation vs illusion

calculation

noun
  • The act or process of calculating. 

  • Reckoning, estimate. 

  • The result of calculating. 

  • An expectation based on circumstances. 

  • The act or process of imagining sequences of potential moves and responses without actually moving the pieces. 

illusion

noun
  • The state of being deceived or misled. 

  • A misapprehension; a belief in something that is in fact not true. 

  • Anything that seems to be something that it is not. 

  • A magician’s trick. 

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