assertion vs ipse dixit

assertion

noun
  • Something which is asserted; a declaration; a statement asserted. 

  • A statement in a program asserting a condition expected to be true at a particular point, used in debugging. 

  • A statement or declaration which lacks support or evidence. 

  • The act of asserting; positive declaration or averment. 

  • Maintenance; vindication 

ipse dixit

noun
  • An authority who makes such an assertion. 

  • A dogmatic and unproved proposition or dictum that is accepted solely on the authority of someone who is known to have asserted it. 

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