reason vs soundness

reason

noun
  • A motive for an action or a determination. 

  • That which causes something: an efficient cause, a proximate cause. 

  • An excuse: a thought or a consideration offered in support of a determination or an opinion; that which is offered or accepted as an explanation. 

  • A premise placed after its conclusion. 

  • Rational thinking (or the capacity for it); the cognitive faculties, collectively, of conception, judgment, deduction and intuition. 

verb
  • To support with reasons, as a request. 

  • To arrange and present the reasons for or against; to examine or discuss by arguments; to debate or discuss. 

  • To persuade by reasoning or argument. 

  • To find by logical process; to explain or justify by reason or argument. 

  • To deduce or come to a conclusion by being rational 

  • To overcome or conquer by adducing reasons. 

  • To perform a process of deduction or of induction, in order to convince or to confute; to argue. 

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. 

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