certainty vs fallacy

certainty

noun
  • The state of being certain. 

  • A fact or truth unquestionably established. 

  • An instance of being certain. 

fallacy

noun
  • An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not; a specious argument. 

  • Deceptive or false appearance; that which misleads the eye or the mind. 

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