It seems to me that the largest or largest complaint people claiming a realist, objective moralist perspective is:
How would it work if morals were not objective?
This is also a common defence by Christians who claim:
If there were no God, then people would just be mindless hedonists.
This is the same line of defence used by statists of all stripes, whether Republican, Democratic, Libertarian, Monarchist, Oligarch, or otherwise.
Anarchy can’t work because everything would just be chaos.
It is also the same argument mounted, as Steven Pinker points out in The Blank Slate, against a strong genetic component to human behaviour.
If we believe that, then what will prevent the next Nazi Holocaust?
In the end, because these people cannot fathom how it might work, it is easy to assuage cognitive dissonance through self-delusion. It’s as if the people defending actually know that they are wrong, but that if they deny it loudly enough, then, like religion, others will believe it’s just so, that they’ll follow the deceiving confederate in a psychology experiment.
The problem is that there is no god, there is no objective morality, government is unnecessary, and much behaviour and temperament have significant genetic foundations unaffected by environmental factors.
Philosophics 
We call something “good” if it meets a real need we have as an individual, as a society, or as a species. Life seeks to survive, thrive, and reproduce. A biologist can tell you, for any given species, what is objectively good for that species and what is objectively bad. This plant needs full sunlight, this other plant needs shade. This fish will survive in fresh water, but will die in salt water. A person who lives off of cake and ice cream will not live as long as one that eats nourishing food.
So, we know that, at least at the most basic levels, what is objectively good for us and what is objectively bad for us. As we move up Maslow’s Hierarchy of Needs, things get more complex. But we can at least state a definition of our objective.
The goal of morality is to achieve the best good and least harm for everyone. Any two rules (ethics), or courses of action, can be compared objectively to the degree that we can objectively measure the benefits and harms they create.
Two moral individuals, however, may disagree as to how a given rule will turn out in the long run. So, we democratically decide upon a working rule, put it in place for a while, and revisit our decision after we have more actual experience.
LikeLiked by 1 person
The concept of ‘good’ is an individual one and not perfectly scalable. To me, a thing might be considered to be ‘good’, whilst to you, it might be considered to be ‘bad’. Therefore, the definition of what is deemed good or bad is merely a consensus-driven phenomenon. Ignoring that life doesn’t really seek as much as it just survives and reproduces (and I’ll consider thriving to be survival hyperbole).
As for biologists, a law of the instrument problem presents itself, but let me step back before coming forward to respond. Nothing is inherently good or bad. A thing is only good or bad in some context, and only then within the context of some constructed language. So to your given species, it might ‘care’ if it survives to procreate—and even some dependant species might care in a food web way—, but the larger universe doesn’t care. In fact, the universe doesn’t need any form of life. It just exists.
Aside from this macro vantage, let’s look at good and bad from the perspective of a weak gazelle and a starving lion. Good and bad are mutually exclusive. What is good for the lion (to sate her appetite; her ability to survive and reproduce) is bad for the gazelle (life; her ability to survive and reproduce), and vice versa. From an outsider’s view, we can rationalise some Spenceresque outcome and say it’s all for the better. Even if this had been the last gazelle, they were unfit to remain a viable species. Ditto for the lion. I’ll skip the plant and fish examples, though I’ll mention that there are many incidences of people eating ‘bad’ diets and outliving other with ‘good’ diets, as this example is single-dimensional in a multidimensional world—and I don’t mean as in a multiverse. 😉
I’ll skip Maslow’s hierarchy of needs as a quaint vestige of pseudo-social-scientific legacy.
One goal of morality, the consequentialist/utilitarian version of it, is ‘to achieve the best good and least harm’, notwithstanding that neither of these is measurable and prospect theory has brought to the forefront that, not only do people register the perception of ‘good’ and ‘bad’ subjectively, they also measure gains (goods) at a value less than losses (bads). This doesn’t undermine utilitarianism wholesale, but it does significantly through off the calculus if gains and losses are not experienced on a 1to-1 ratio. In any case, it is not true that we can compare options ‘objectively to the degree that we can objectively measure the benefits and harms they create’. In fact, this is a matter of subjective perspective.
That two moral individuals, however, may disagree as to how a given rule will turn out, will be determined in time, but this probabilistic nature of this only underscores the subjective as opposed to objective nature of morality, or ethics, as we’ve slipped into. Democratically determining ethics is an approach, though this has left us with slavery and torture as ethical practices. In Plato’s Republic, mouthpiece Socrates had a few disparaging things to say about Democracy. In fact, he argued how Democracy would necessarily lead to Oligarchy. I am not a fan of Classical philosophers such as Plato, but he may have been spot on there. The problem is that his facile rendition of a Republic is a bit wanting.
LikeLike
All of your points are well taken.
As to the gazelle and the lion, moral judgment is necessarily species specific. What’s good for the polio virus is not good for us.
As to the objectivity, we can find some hope of this in the fact that everyone agrees that it is objectively good to give a glass of water to the man dying of thirst in the desert, and that it is objectively bad to give that same glass of water to the man drowning in the swimming pool. As we move up from the basic physical needs, things do get a lot fuzzier.
I believe the framework is valid. And I would even assert that everyone is already using it, especially when their deontological rule systems clash.
The requirement that it be “the best good and least harm for everyone” is because, as you say, it will be consensus driven, and that is the only thing that everyone can agree to.
LikeLiked by 1 person
Thanks for responding. We can agree to disagree (or merely disagree to agree as the case might be). As Plato noted, consensus is a silly form of governance. As Tocqueville noted, ‘a democracy requires an educated populace’, and there is too much to know across too many interacting domains for this to work at any significant scale due to increasing fuzziness. I agree with each of them. I just don’t happen to agree with Plato’s ‘logical’ conclusion, rather, it’s a hair’s breadth from a plea for a benevolent dictator, though benevolence would seemingly not be a factor in his consideration.
As to everybody ‘already using it’, societies existed prior to Bentham and Mill, and society may exist under any number of other alternatives.
LikeLike
The definition of morality as “the best good and least harm for everyone” precedes any philosopher you’ve read. I’m told that Jesus was quoting someone in the Old Testament when he repeated the “Great Commandment” in Matthew 22:35-40. As a Humanist, I paraphrase it this way, “Love Good. And love it for your neighbor as you love it for yourself. ALL OTHER RULES ARE DERIVED FROM THESE TWO”.
So, I’m working under the presumption that “the best good and least harm for everyone” is behind every rule that our consequentialists have created, and which our deontologists then propagate as “the word of God”. 😇
LikeLiked by 1 person