extrapolation vs postulation

extrapolation

noun
  • An inference about some hypothetical situation based on known facts. 

  • A calculation of an estimate of the value of some function outside the range of known values. 

  • The diametric opposite of interpolation. 

postulation

noun
  • Something self-evident that can be assumed as the basis of an argument. 

  • The act of postulating or something postulated. 

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