doubt vs prior knowledge

doubt

noun
  • Disbelief or uncertainty (about something); (countable) a particular instance of such disbelief or uncertainty. 

verb
  • To be undecided about; to lack confidence in; to disbelieve, to question. 

prior knowledge

noun
  • Knowledge of a set of circumstances sufficient to make actions based on those circumstances wrongful. 

  • Prior to the inception of an insurance policy, knowledge of specific extant circumstances that could reasonably give rise to a claim under that policy. 

  • Used other than figuratively or idiomatically: see prior, knowledge. 

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