demonstrable vs imperceptible

demonstrable

noun
  • Something that can be demonstrated. 

adj
  • Able to be demonstrated. 

imperceptible

adj
  • beyond the purview of man; too great and all-encompassing to be perceived. 

  • not perceptible, not detectable, too small in magnitude to be observed 

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