Whenever a moral issue is raised, the reflex of many people is to spout, “Who is to say what is right or wrong?”

This is the wrong question.  The right question isn’t “Who is to say?” but “How can we find out?”

The former question takes for granted that there is no way to find out.  This ignores centuries upon centuries of moral inquiry.

It is like saying, “Who is to say whether the moon is made of rock or of cheese?,” ignoring centuries upon centuries of astronomical inquiry.

“But people disagree.”  Sure.  Some people disagree about the moon, too.  Ethics is harder only because if we get an answer we don’t like, we may have to change our lives.  That’s much harder than just changing our minds – and that is hard enough.