soundness vs validity

soundness

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

  • The result or product of being sound. 

  • 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. 

validity

noun
  • The state of being valid, authentic or genuine. 

  • The genuinity - as distinguished from the efficacity or the regularity - of a sacrament as a result of some formal dispositions being fulfilled. 

  • State of having legal force. 

  • A quality of a measurement indicating the degree to which the measure reflects the underlying construct, that is, whether it measures what it purports to measure (see reliability). 

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