There is no explanation, no meaning, no real understanding. Twenty-eight people — 20 of them children barely 6 and 7 years old — murdered in an act of incomprehensible pitilessness is something around which we simply cannot wrap our minds. And yet, we must. We must finally begin to think and speak in a reasonable, rational way about the issues that underlie this horrific tragedy in Connecticut. The issues are threefold: guns, mental health and our national culture of violence. America has a long-standing love affair with guns. When I was a child growing up in Auburn, almost every home …