Ken:"There has to be an objective morality because otherwise terms like “right” and “wrong” would be meaningless, since they have no foundation for comparison. "
Rob:"The terms “right” and “wrong” are based on cultural norms, which do have a subjective foundation -- one that changes as the moral sphere of the culture changes. The term “heavy” does not have an objective standard, yet we have no problem using that term in a meaningful way. In fact, very few relational terms have any kind of objective foundation."
Ken:"But without an objective morality, we would all be lost morally as a race."
Rob:"Many would say that we are."
Ken:"But how can you say that torturing children for fun is morally acceptable in any situation?"
Rob:"Personally, I wouldn’t, but you are implying that anything that is not objective must necessarily be seen in all possible ways. A feather may not be seen as “heavy” to anyone, but that doesn’t mean its “lightness” is still not relative to other objects."
Ken:"But God is the standard of objective morality. Prove that wrong!"
Rob:"That I cannot do."
Ken starts with a statement explaining why he thinks there has to be an objective morality -- a statement based on a reasonable argument that can be pursued with reason and logic. Rob adequately answers that objection, as indicated by Ken’s move away from that objection to a new objection. This pattern continues until we arrive at an impossible request. Despite all the objections being adequately answered, at no time does Ken concede any points or abandon the argument.