discursion vs obiter dictum

discursion

noun
  • Ratiocination; step-by-step philosophical reasoning, as opposed to intuition. 

  • Digression. 

obiter dictum

noun
  • An incidental remark; especially (law) a statement or remark in a court's judgment that is not essential to the disposition of the case. 

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