why and wherefore

why and wherefore (plural whys and wherefores)

1. (set phrase, often pluralized) A full and complete explanation.
   • 1879, W[illiam] S[chwenck] Gilbert, Arthur Sullivan, composer, H.M.S. Pinafore;  […], San Francisco: Bacon & Company,  […], →OCLC:

     Never mind the why and wherefore, / Love can level ranks, and therefore, / Though his lordship's station's mighty / Though stupendous be his brain.

   • 1888, J[ames] M[atthew] Barrie, “(please specify the page)”, in Auld Licht Idylls, London: Hodder and Stoughton, […], →OCLC:

     Bursting into the kirk she called the office-bearers to her assistance, whereupon the minister in miniature raised his voice and demanded the why and wherefore of the ungodly disturbance.

   • 1922, D[avid] H[erbert] Lawrence, “First Steps in Education”, in Fantasia of the Unconscious, New York, N.Y.: Thomas Seltzer, →OCLC, pages 111–112:

     Those whose nature it is to be rational will instinctively ask why and wherefore, and wrestle with themselves for an answer. But why every Tom, Dick and Harry should have the why and wherefore of the universe rammed into him, and should be allowed to draw the conclusion hence that he is the ideal person and responsible for the universe, I don't know.

   • 2015 February 16, Vanessa Friedman, “At New York Fashion Week, Whatever Looks Warm Will Work”, in New York Times, retrieved 17 June 2018:

     [T]ruth be told, once clothes make it into the stores, the why and wherefore of their creation in the designer mind is essentially beside the point.