I'm saying that the notions of right and wrong come firstly from our human nature, secondly from our society and so on. Last in this list is ethics as personal

I'm saying that the notions of right and wrong come firstly from our human nature, secondly from our society and so on. Last in this list is ethics as personal preference or "something private" as Linus likes to call it. And even if it does vary wildly in current cultures, there is such a thing as a sense of morals that we can combine with rational thought to reach a fair solution. The fact that culture A considers ritual murder ok fails this morals + rational though test.