posit vs surmise

posit

verb
  • Assume the existence of; to postulate. 

  • Propose for consideration or study; to suggest. 

  • Put (something somewhere) firmly; to place or position. 

noun
  • Something that is posited; a postulate. 

surmise

verb
  • To imagine or suspect; to conjecture; to posit with contestable premises. 

noun
  • Thought, imagination, or conjecture, which may be based upon feeble or scanty evidence; suspicion; guess. 

  • Reflection; thought; posit. 

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