The role of observation in ethics

An short analysis of our in class readings: 
The belief that scientific theories are theory-laden is not uncommon. In our readings for this week we can notice that Sturgeon agrees with Harman about the aforementioned. It seems like Sturgeon is saying that theory can be good for observation, and that the observation can justify the theory simultaneously. Essentially, unlike Harman, Sturgeon seems to think that moral theories can be tested in the way that scientific theories can be tested. He offers the hitler example, in which Hitler can be viewed as an amorally admirable person or a morally vicious person, similar to science, where we have theory choice. He believes that both science and morality are no different when it comes to the explanatory chain between them, and observation. In response to Harman, Sturgeon claims that moral beliefs can be rejected when they are not consistent with other moral beliefs and observations. For, Sturgeon this is exactly like science. We believe facts because we believe them to be true. Overall, Sturgeon accepts that ethics is scientific in that it can be a reliable source of knowledge and that moral facts can cause the world to be a certain way. He thinks that Harman does not succeed in convincing us that moral facts don't cause the world to be a certain way.
Essentially, Harman considers whether moral principles can be tested and confirmed in the way scientific principles can. He conducts a thought experiment to confirm and test a moral principle but concludes that ethics has an apparent immunity from observational testing. The more precise challenge that comes from this claim is that we can never objectively know that any moral belief or value is wrong or right because of this gap in the explanatory chain from the principle of observation to morality. Harman explains that this often is the explanation as to why moral nihilists hold their positions. If nothing can be decisively wrong or right, then morality cannot be objective. More specifically, this is a challenge because what we perceive may be dependent on preconceived notions. And so, if we attempt to justify something we observe as being morally wrong, our experiences and cultural beliefs play into our conclusions, and so though we may believe something is wrong simply because the act itself is wrong- our preconceived notions are more than likely factoring into our observations. He offers the kids burning a cat example. So many different beliefs factor into whether what we see can be deemed morally wrong or morally acceptable. For example, we hold beliefs about animals, and separate from that, beliefs about kids, and so on. Unlike in science, we cannot test our observations by objective standards, and so we can never truly justify our moral observations.  This certainly seems like a plausible view. However, people still so use justifications to explain their moral actions. This happens every day. Is it really problematic that we cannot test our observations in the same way that science does? Additionally, many claim that theory choice in science as well as the entire  process of science itself, contains subjectivity and so we cannot categorize it as privileged or as an authority to tell us how the world really works. In other words, that science cannot tell us objective truths about the world. If this is the case, it seems that Harman would need to re-think his claims, and it seems that what he conceives to be problematic, isn't really as problematic when science isn't an authority either in regards to testing our observations in search for objective truths.