certainty vs presumption

certainty

noun
  • An instance of being certain. 

  • The state of being certain. 

  • A fact or truth unquestionably established. 

presumption

noun
  • the act of presuming, or something presumed 

  • the condition upon which something is presumed 

  • the belief of something based upon reasonable evidence, or upon something known to be true 

  • An inference that a trier of fact is either permitted or required to draw under certain factual circumstances (as prescribed by statute or case law) unless the party against whom the inference is drawn is able to rebut it with admissible, competent evidence. 

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