instability vs understanding

instability

noun
  • The quality of being unstable. 

  • A state that is not in equilibrium, or in which a small change has a large irreversible effect. 

understanding

adj
  • Showing compassion, tolerance, and forbearance. 

noun
  • Opinion, judgement or outlook. 

  • An informal contract; mutual agreement. 

  • A reconciliation of differences. 

  • The act of one that understands or comprehends; comprehension; knowledge; discernment. 

  • Sympathy. 

  • Reason or intelligence, ability to grasp the full meaning of knowledge, ability to infer. 

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