soundness vs stability

soundness

noun
  • The result or product of being sound. 

  • The property (of an argument) of not only being valid, but also of having true premises. 

  • The property of a logical theory that whenever a wff is a theorem then it must also be valid. Symbolically, letting T represent a theory within logic L, this can be represented as the property that whenever T⊢𝜙 is true, then T vDash 𝜙 must also be true, for any wff φ of logic L. 

  • The state or quality of being sound. 

stability

noun
  • The tendency to recover from perturbations. 

  • The condition of being stable or in equilibrium, and thus resistant to change. 

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