A moral system that is not based on the interpretation of a book, is surely superior.
To explain this lets I will tell you about myself and my Cousin. I am an atheist and have never had a belief in God, my Cousin is Catholic.
From an earlier age we'd both been told being Gay was wrong and unnatural, luckily for both my cousin and myself we don't have homosexual feelings and so it was easy to carry on with the belief that it is wrong.
This continues until we are both 12 and my dad witnesses both throwing stones at a boy we thought was Gay. He takes us both home and lays down the law, asking us both why we hate someone for being gay so I answer:
1) It is unnatural - Dad answers - Ducks/Dolphins/ etc are gay -
2) They choose it - Not they don't why would they choose to have 2 morons throwing stones at them being thrown out of their families
3) They are going to Rape me - Gay does not = Rapist
That's it for me I, not straight away but within a month my mind has been changed. I will go on to march of gay marriage, and have many amazing friends who are Gay.
My cousin says answers only with this:
1) God says its wrong! end of discussion.
I am able to change my mind when evidence is presented to me, I am able to evolve as my knowledge and experiences grow. And more importantly When I have a moral view I need to intellectually defend that view (even if it is only to myself).