A show-stopper for Chapter 6

That point in the thesis was really where the external reviewer got angry. He is obviously very opposed to sociological functionalism. However, it does seem fair enough to give this part of the thesis more support, because it is a critical turning point in how the theory of ethics will take shape. You also don't want to beg the question in favour of sociological functionalism by overtly moving in that direction too soon. For example, my sociology lecturer would have said that sociological functionalism presupposes a conservative political view. Other political views are also possible, namely radical (presupposed by Marxism) and liberal (presupposed by Weberianism). In fact, it is well known that sociology has no dominant paradigm, which is why it does not qualify as science. Therefore, you cannot accept Lord Patrick Devlin's answer to the question 'Why be moral?', at least not simpliciter. It begs the question in favour of a conservative political viewpoint.

But that is an interesting question, whether an established moral system is indeed an essential of social functioning. If it is, then this suggests that there would be legitimate social pressures on the moral.

But I think that part of the problem here is that your basic methodology is flawed. You already allow that ethics cannot reduce to anything other than ethics. Therefore, the only thoroughgoing answer that you are ever going to get to the question, 'Why be moral?' will be circular. The notion that you can answer a question like that in extramoral terms already presupposes a reductive project, which you have already stated that you reject. Therefore, this--fairly basic--part of chapter 6 has already been invalidated. Even though the external reviewer was unjustifiably vitriolic with your work, you cannot deny that he did make some helpful points, once you got past his animosity.