Let me start with an example.
Let's assume I'm a computer scientist working on autonomous, human-like (at least in some aspects) artificial intelligence, which is expected to interact with humans, make important autonomous decisions, etc. Not getting too much into details, there are numerous open ethical questions regarding this matter, and some people claim that (for different reasons) creating human-like AI would be immoral, and (what follows) the research itself (even if it doesn't involve any actual creation) is immoral, too, as it brings us closer to the implementation of it (just like, say, research on nuclear bomb). It's not my intention to discuss those arguments here. I think we can agree, however, that the problem is highly controversial, there is no universally acknowledged authority or ethical stardard we could turn to, and therefore it's uncertain if working on AI is moral or not.
Given the situation I just described: is it moral (for me) to work on human-like AI if I don't know if it's moral?
If I'm an engineer building a bridge, I'm not expected to know the exact proof of every mathematical equation I'm using; still, I should at least be able to point at a reliable textbook where the proof can be found. If I'm an experimental psychologist, there's a commision which will decide if my experiment design is ethical or not. I believe there's a general consensus that, whatever I do, I should "do my homework", but in both mentioned cases there's a higher instance I'm allowed to trust. However, if no such instance exists, what is my moral obligation? Should I first become an expert in ethics of AI, to be able to make the best decision possible, before I can continue my research (or abandon it)?
I chose the above example because it's relevant to my situation and also a problem both difficult and practically important. Yet I would like to make my question much more general: Is it moral to do anything without knowing whether it's moral or not?
To be clear, obviously I don't suggest that one can determine the validity of normative statements in an empirical or apriorical manner. By "knowing what's moral" I mean: getting the best possible overview of existing arguments and making the most educated and impartial decision as to what seems to be the right thing to do.
I would like to hear some good arguments for and against within a utilitarian framework.