fallacy vs validity

fallacy

noun
  • An argument, or apparent argument, which professes to be decisive of the matter at issue, while in reality it is not; a specious argument. 

  • Deceptive or false appearance; that which misleads the eye or the mind. 

validity

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

  • The state of being valid, authentic or genuine. 

  • 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 fallacy and validity occurred in a corpus of books? (source: Google Ngram Viewer )