whys and wherefores

whys and wherefores pl (normally plural, singular why and wherefore)

1. (set phrase) The reasons or motivations for a fact, action, or decision, especially the complete set of such reasons or motivations.
   • 1887, George Bernard Shaw, chapter 5, in An Unsocial Socialist:

     I can no more tell you the whys and wherefores of myself than I can lift myself up by the waistband and carry myself into the next county.

   • 1908, Lucy Maud Montgomery, chapter 1, in Anne of Green Gables:

     [I]f she noticed anything odd or out of place she would never rest until she had ferreted out the whys and wherefores thereof.

   • September 5 2004, Albert M. Forget, “Question integrity of vets attacking Kerry”, in Seattle Post-Intelligencer‎:

     Of the hundreds of thousands who served in Vietnam, most still do not understand the whys and wherefores of our involvement.

• explanation

• “whys and wherefores”, in OneLook Dictionary Search.