  The first cluster concerns the sociological reality of moral disagreement. Obviously the group-centered conception of moral knowledge does not eliminate differences in moral outlook, but it may alter how we should think about these differences. I said early on that I would assume that we have knowledge of some non-moral truths. An example would be knowledge that the Earth is round rather than flat. There are pockets of people who still believe that the Earth is flat. Should most remain confident in knowing that the Earth is round? The reason they should is the social interactive reasoning about the issue over centuries from diverse perspectives leading to near universal agreement. Can a similar conclusion be drawn in certain important cases of moral agreement, for example, about moral progress?