empiricism vs proving ground

empiricism

noun
  • A pursuit of knowledge purely through experience, especially by means of observation and sometimes by experimentation. 

  • A doctrine which holds that the only or, at least, the most reliable source of human knowledge is experience, especially perception by means of the physical senses. (Often contrasted with rationalism.) 

  • used to describe research based on methodology shaped from empirical philosophy (see above), e.g. surveys, statistics, etc. 

  • Medicine as practised by an empiric, founded on mere experience, without the aid of science or a knowledge of principles; folk medicine, quackery. 

proving ground

noun
  • A venue or project in which new technologies, methods, or techniques are tested. 

  • A terrain or installation for testing weapons, military equipment, or tactics. 

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