epistemology vs gnostology

epistemology

noun
  • A particular instance, version, or school thereof; a particular theory of knowledge. 

  • The branch of philosophy dealing with the study of knowledge; theory of knowledge, asking such questions as "What is knowledge?", "How is knowledge acquired?", "What do people know?", "How do we know what we know?", "How do we know it is true?", and so on. 

gnostology

noun
  • Synonym of gnosiology 

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