Okay, Skeptic Ginger.
https://plato.stanford.edu/entries/morality-biology/#EvoMet
1.1 Three Kinds of Appeal to Evolution in Evolutionary Ethics
Talk of ‘evolutionary ethics’ may suggest a well-defined field of inquiry, but in practice it can refer to any or all of the following:
Descriptive Evolutionary Ethics: appeals to evolutionary theory in the scientific explanation of the origins of certain human capacities, tendencies, or patterns of thought, feeling and behavior. For example: the appeal to natural selection pressures in the distant past to explain the evolution of a capacity for normative guidance, or more specifically the origins of our sense of fairness or our resentment of cheaters. (See section 2.)
Prescriptive Evolutionary Ethics: appeals to evolutionary theory in justifying or undermining certain normative ethical claims or theories—for example, to justify free market capitalism or male-dominant social structures, or to undermine the claim that human beings have a special dignity that non-human animals lack. (See section 3.)
Evolutionary Metaethics: appeals to evolutionary theory in supporting or undermining various metaethical theories (i.e., theories about moral discourse and its subject matter)—for example, to support a non-cognitivist account of the semantics of moral judgment (the idea that moral judgments do not purport to represent moral facts but instead just express emotions, attitudes or commitments), or to undermine the claim that there are objective moral values, or to cast doubt on whether we could have justified beliefs about such values. (See section 4.)
Compare the highlighted parts:
The first one: If cheating is a biological fact, i.e. there are humans, who cheat as a biological feature and humans, who resent cheaters, what does it tell us?
That cheating and resenting cheaters are both facts. Now how do you then declare one fact morally right and the other morally wrong?
How can a fact be morally right or wrong? Answer that.
The second one: "... to justify free market capitalism or male-dominant social structures ..." That would mean that e.g. #MeToo and the idea of a welfare state is problematic, because they could lack scientific grounding. I bet you disagree!
The third one: "... the idea that moral judgments do not purport to represent moral facts but instead just express emotions, attitudes or commitments ...", "...undermine the claim that there are objective moral values..." and "... whether we could have justified beliefs about such values ...".
This one is where the actual meat is, because your claim of using science amounts in philosophical terms, that there are moral facts, objective moral values(that follows from your methodology) and you have justified beliefs about such values.
Now to the conclusion of the paper:
Thus, although the evolutionary story fits naturally with a merely non-cognitivist metaethical view, it may fit equally well with a cognitivist view. If one rejects the existence of moral truths, the latter would then lead to an error theory (Mackie 1977). But as discussed in section 4.1, it is far from clear how much support evolutionary biology itself lends to moral anti-realism or irrealism. It is consistent with plausible evolutionary stories that although our capacities for normative guidance originally evolved for reasons that had nothing to do with moral truths as such, we now regularly employ them to deliberate about and to communicate moral truths. So all three metaethical views discussed here—expressivism, error theory and moral realism—remain on the table.
Notice that this paper doesn't support neither your view or mine as such. You are a moral realist and I am in favor of expressivism and error theory.
So you solved nothing, because this overview show that science doesn't support neither your view nor mine. I.e. the jury is still out on this one.
But it is possible to solve it. It is simple.
Take flying, the movement through air. Humans can't do that as humans, no human can fly unaided. That is an objective fact; i.e. it is common to all humans.
Now take morality and observe that there is no common morality to all humans. That is also an objective fact; i.e. you state without bias and judgment what you observe.
There are no objective morality, because we can't observe objective moral facts.
So how do we explain that humans can disagree over whether there are objective moral facts. Because all, who claim that there are objective moral facts, in fact claim that their subjective bias is an objective moral fact.
That is it. That is no unique to you, but rather common among humans.
Look here:
There does not seem to be much reason to think that a single definition of morality will be applicable to all moral discussions. One reason for this is that “morality” seems to be used in two distinct broad senses: a descriptive sense and a normative sense. More particularly, the term “morality” can be used either
- descriptively to refer to certain codes of conduct put forward by a society or a group (such as a religion), or accepted by an individual for her own behavior, or
- normatively to refer to a code of conduct that, given specified conditions, would be put forward by all rational persons.
And now I will show you what always happens:
Take a fact. Humans kill other humans. Rewrite to fit A is B and state it as a premise:
Premise 1: Killing of other humans is a fact.
Now add a conclusion:
Premise 1:
Killing of other humans is a
fact.
Conclusion:
Killing is
wrong.
Rewrite it to letters:
P1: K is F
C: K is W
The conclusion is invalid.
It doesn't matter how specific you go on a given moral code. You need to add at least one more premise. Now what you will find is that one necessary premise to support the conclusion, is not a statement of a fact. It is a biased evaluation.
All normative morality is a bias. It is a bias, because it is always a subjective evaluation, a weighing of a fact as either right or wrong. But facts are never morally right or wrong. You can't observe morally right or wrong. Right and wrong has no observer independent referent.
Any signs including words have 3 parts. It is a sign. Its meaning is not in the sign, that is in a brain. And the sign is about something, the sign has a referent.
A host of words have no objective referent, because what they are about are subjectivity; i.e. the evaluation of facts as how they
matter to a person or group. "Matter" is the subjective part.
And here is the final straw to objective moral facts. The fact, that we can disagree, is the evidence. that it is subjective.
Compare with flying unaided. That is the difference. We can't change common objective facts, they are common to all humans, but morality and subjective are not objective and that is how we can disagree.
If you disagree, you give evidence to fact that morality is subjective, because that you can disagree, is because it is subjective.