I think it is evolving, in fits and starts and with many setbacks -- in my own lifetime I have seen huge advances in the way blacks and gays are treated. I think the reason it evolves is that we do sometimes learn from our mistakes, and because new circumstances make us re-think old ways of doing things. But I'm not sure that there's any predictable direction, and there is still always a real chance we'll screw everything up. The Roman Empire fell, and the advances made by the classical civilizations were lost for a thousand years.