affirmation vs substantiation

affirmation

noun
  • That which is affirmed; a declaration that something is true. 

  • A form of self-forced meditation or repetition; autosuggestion. 

  • The solemn declaration made by Quakers and others incapable of taking an oath. 

substantiation

noun
  • Something which substantiates; evidence, proof 

  • The act of substantiating 

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