What does Wiesel mean by “responsibility is the key word

SOMETIMES I AM ASKED if I know "the response to Auschwitz"; I answer that not only do I not know it, but that I don't even know if a tragedy of this magnitude has a response. What I do know is that there is "response" in responsibility. When we speak of this era of evil and darkness, so close and yet so distant, "responsibility" is the key word.