Jon Morrison said this quote
“ Think about goodness like you think about gravity. Whether or not you believe in gravity, it is still there. Every day you are affected by gravity regardless of how well you understand the physics of it. In this chapter I am asking whether objective morality is something like gravity operating in accordance with the laws of the universe. Are there some things that are always right and some things that are always wrong? Put another way, has there ever been a time in history where it would have been acceptable for Hitler to kill over five million Jews? Or is mass murder always wrong no matter when or where you are? If mass murder is always wrong, then it turns out that objective moral values and duties do exist. ”