This is sensible enough as a theory of morality, but you still haven't accounted for ethics, or the practice of engaging in interpersonal arguments about moral values. If Bob!morality is so clearly distinct from Frank!morality, why would Bob and Frank even want to engage in ethical reasoning and debate? Is it just a coincidence that we do, or is there some deeper explanation?
A possible explanation: we need to use ethical debate as a way of compromising and defusing potential conflicts. If Bob and Frank couldn't debate their values, they would probably have to resort to violence and coercion, which most folks would see as morally bad.
Well, I agree with your second paragraph as a possible reason, which on its own I think would be enough to make most actual people do ethics.
And while Bob and Frank have clearly distinct moralities, since both of them were created by highly similar circumstances and processes (i.e. those that produce humans brains), it seems very likely that there's more than just one or two things on which they would agree.
As for other reasons to do ethics, I think the part of Frank!morality that takes Bob!morality as an input is usually rather important, at least in a c...
I think there’s a confusion in our discussions of deontology and consequentialism. I’m writing this post to try to clear up that confusion. First let me say that this post is not about any territorial facts. The issue here is how we use the philosophical terms of art ‘consequentialism’ and ‘deontology’.
The confusion is often stated thusly: “deontological theories are full of injunctions like ‘do not kill’, but they generally provide no (or no interesting) explanations for these injunctions.” There is of course an equivalently confused, though much less common, complaint about consequentialism.
This is confused because the term ‘deontology’ in philosophical jargon picks out a normative ethical theory, while the question ‘how do we know that it is wrong to kill?’ is not a normative but a meta-ethical question. Similarly, consequentialism contains in itself no explanation for why pleasure or utility are morally good, or why consequences should matter to morality at all. Nor does consequentialism/deontology make any claims about how we know moral facts (if there are any). That is also a meta-ethical question.
Some consequentialists and deontologists are also moral realists. Some are not. Some believe in divine commands, some are hedonists. Consequentialists and deontologists in practice always also subscribe to some meta-ethical theory which purports to explain the value of consequences or the source of injunctions. But consequentialism and deontology as such do not. In order to avoid strawmaning either the consequentialist or the deontologist, it’s important to either discuss the comprehensive views of particular ethicists, or to carefully leave aside meta-ethical issues.
This Stanford Encyclopedia of Philosophy article provides a helpful overview of the issues in the consequentialist-deontologist debate, and is careful to distinguish between ethical and meta-ethical concerns.
SEP article on Deontology