If you are an emotivist this is not a particularly relevant question. You decide based on what suits your own disposition. People tend to prefer things that benefit them. An entirely selfish or selfless person will soon come to realise that you have to be selfless and selfish to some degree respectively.
If something 'feels' right to you it feels right. You can of course come to change your mind about it with more information. If your feelings do not fit into societal norms you then bend them to your will as best you can or suck it up. The culminative effect has been what we broadly refer to as 'morality' but I see no reason to say 'killing people is wrong' is necessarily a True statement.
What I personally find most intriguing is the interplay between normative values across different domains, and exactly how different such domains really are. If anything I think the most moral act anyone can make is to sacrifice their own sense of morality for the betterment of others because I am someone who values humanity. I 'feel' that human is good.
Every moral position (realist or otherwise) has problems logically. I think this is simply because there is more to life than abstract truths.
The main argument against an emotivist position that adherents of it tend to struggle with is precisely what you outlined. If there is no point from which two people can agree on then it is impossible to figure out a better course.
Here are two problems with this criticism.
(1) Can this be at all possible? Can two people never come to a general agreement about anything deemed 'moral' from which to build a common understanding from.
(2) Even if it is granted that (1) is possible, then does this criticism not also lie at the feet of every moral theory there is? Meaning, just because someone says or believes they are not X or are Y does this mean they actually are. The subjective nature of the kinds of problems involved in ethics means people either stop thinking and resort to a theoretical framework that suits their 'gut feeling' (altruism, some form of consequentialism, or perhaps deontic stance), rather than actually tackle the reasons they feel they way they do as opposed to what they think is 'right' or 'wrong' or how they morally 'ought to' feel about this or that.
I am unsure. I remain unsure. I have experiences that have given me certain insights, but they are wholly subjective so I simply have to do as I do and question as I go.
The labels we use serve a purpose in discourse not as a picture frame for reality. I do see too many adhering to 'emotivism' or 'virtue ethics,' or whatever other niche carved out in the landscape of ethics, as if it is a writ physical law they must abide by.
They are all useful and contrastign perspectives that can allow us to understand others thoughts and actions as well as our own. I still end on the simple thought that people 'feel' this or that way is better suited to them at this or that given moment. If I need a label to sketch my ethical disposition it is as some kind of emotivist, but (big BUT!) it tells you very, very little about how I regard other people's views and values, how I judge them, if I judge them, and what actual moral theories I may feel are better generally, or specifically in certain contexts.
But this doesn’t resolve the problem — Tom Storm
I do not see a problem. Meaning, I do not think it makes sense to view such as problematic. It is a bit like saying 'life is problematic' .. well, yeah! If it was not would we bother doing anything. Problems are good things not bad things; unless you 'feel' otherwise of course
;)
As an explicit example you can ask anyone this simple question:
"What is the biggest problem you have?"
Then whatever they may say think about whether or nto they have really said anything much other than "I do not like this thing" understanding that underneath it there is a whole invisble world upon which such claims remain oblivious to.
I recommend Bernard Williams' 'Ethics and The Limits of Philosophy' if you wish to dive deeper (note: he is not an emotivist).