discerning vs soul-searching

discerning

adj
  • Of keen insight or good judgement; perceptive. 

noun
  • discernment 

soul-searching

adj
  • Involving probing introspection, or a critical consideration of one's conscience, especially motives and values. 

noun
  • Probing introspection; a critical consideration of one's conscience; also, an instance of such consideration. 

How often have the words discerning and soul-searching occurred in a corpus of books? (source: Google Ngram Viewer )