Ethics is a tricky problem in philosophy (its been a “hot topic” for thousands of years after all). Here is an example of one kind of problem faced by modern ethical theories: when studying ethics we rely on our ethical intuitions to reject theories (or at least cast doubt upon them), as well as to lead us to propose what we think might be fundamental principles of moral behavior. However we also want to assert that there is such a thing as objective ethical truth, independent of people, and if that is the case what do our intuitions have to do with ethics? Our intuitions are formed by how we were raised, and what ideas we were exposed to when we were growing up, and it doesn’t seem like our upbringing has a greater or lesser of a claim to tracking the objective ethical truth than anyone else’s (in the absence of a definition of what objective ethical truth is). There is also the problem of normativity in ethics. We think that ethical truths should inform people as to what they should do in matters of right and wrong, which makes constructivist accounts a bit hard to believe, since one can always reject the axioms their ethics are constructed from (there is no normative reason not to reject the fundamental principles). On the other hand if we argue that ethical behavior is good for the individual (and should be motivational for that reason) then we seem to undercut the possibility of a pure ethical action (or so it seems to me), since then a person’s so-called ethical actions are motivated simply by self-interest (and is that what it means to do the right thing?).
One step towards progress is probably to limit the scope of what is included in an ethical theory. Currently we see ethical theories as being about what is good, in general, but I think that they should only be about what is morally good. How is this different? Well a theory that attempt to tackle good runs into a problem of defining what good is. For example there is a good way to drive, what is good for the individual, ect. Ethical theories often then attempt to address what is good in the absence of a context (not good for some end, simply good) with the expectation that what is simply good will be motivational because it is good. This generally leads to confusion, so I propose that ethics should only attempt describe what is morally good (and we will just assume that claims about something being good, with no end in mind, mean morally good or are simply confused), and an action is morally good only if agrees with the “laws” of ethics (whatever we discover them to be). This means that we are no longer able to appeal to what is good (either with no context or in the sense of morally good) for fear of being circular (and this is probably progress). If we accept this then we will also need to explain why a person should be ethical, and what being ethical is (what the ethical “laws” are), but at least now we can analyze actions with respect to some features of those actions, such as ends they can achieve well or poorly, in order to determine if they are morally good or not.
The situation we find ourselves in reminds me of psychologism (probably because I have been reading Husserl’s Logical Investigations as of late). Psychologism, briefly, is the idea that the “truths” of logic are only valid because they reflect psychological facts about reasoning. This reminds me of our situation current situation in ethics because, like logic, we want to say that ethics is independent of people, and a priori, but at the same time our “axioms” seem to be derived from our psychology (our intuitions), which has no necessary connection to such truths. This issue was resolved, with respect to logic, by arguing that logic was an abstract system, like any system of mathematics, and that with the right correspondence rules the theorems and laws of logic track objective truth in the world. Our psychology tends to follow these rules not because it creates them, but because the ability to track the truth is useful (psychology instantiates the abstract system of logic, albeit in a limited fashion and with some mistakes).
How can we apply this solution to ethics? Well we will simply assume that there is some abstract mathematical system that is ethics (even though we don’t know what it is yet, obviously that would be the subject of a “scientific” investigation into ethics). We must also assume that there are some correspondence rules between this system and some real features of the world (which for logic was objective truth), as well as a reason that the correspondence rules plus the abstract ethical system should be useful to us. I propose (although I don’t have an ironclad argument for this yet) that the abstract system of ethics corresponds to ways to maximize human happiness and productivity, as well as the productivity of society as a whole. Unlike utilitarianism, I suspect that these rules only advocate increases in happiness and productivity, not sacrificing that of one individual for that of another. Obviously I haven’t worked out all the details (yet). Of course it is obvious why such rules would be useful to people, since most people would consider the happiness of themselves and their neighbors, as well as the productivity of the community they are part of it, to be useful to them. This also explains why we have ethical intuitions, because these rules benefit the individual and their community, and thus evolution / social norms have selected for a psychology that instantiates them (albeit in a limited fashion and with some mistakes).
In summary then here are the ideas that I have introduced here (although not adequately defended): not every action or choice is a matter of ethics; the objective ethical system is as a priori and abstract as any mathematical theory; the ethical system can be interpreted as rules leading to the increased happiness for individuals and productivity for the community; ethics consists of considerations both for the individual and the community; because ethics is useful there is a rational reason why everyone should be ethical (ethics is normative).
Final note: another possibility as to what the objective abstract ethical system might correspond to is ways to maximize that which individuals see as valuable as well as what the community sees as valuable, but since this introduces the painfully vague concept of something being of value I have decided to start initially with only the happiness and productivity version.