I went back to your OP to see if I could find where the problem is. I think the “positivists” have set up a straw man with their “Value-free” and “assumed standard” for Natural Law, with the latter thought to be some objective, omnipotent, universal truth. It’s not and no one ever said it was. And the essence of Natural Law is Values.
In the beginning, man had lots of feelings. Five of those were feelings of what is good, what is bad, what is right, what is wrong, and what is just. He found these feelings to be valuable to his daily life.
However, his feeling of what is just compelled him to justify his feelings before reducing that which was valuable to values. So, he used reason to justify his feelings. In the end, he had a reason. All of this, and I mean all of it, preceded and provided the reason for his Johnny-come-lately written law.
There was not universal agreement on feelings. Bob’s clan over here felt that FGM was good, and right, and just, and valuable. FGM became a value, it was justified and this formed the reason for law.
There was Sam’s clan over there who felt that FGM was bad, and wrong, and unjust and not valuable. It was not a part of their values so they did not reduce it to law. In fact, after they saw or heard about Bob’s clan, they drafted a law against FGM.
Where one man might say that a failure to recognize his law does not mean his law does not exist, so too, a failure to recognize Natural Law does not mean Natural Law does not exist. And neither Natural Law or the law are inviolate. Both are disagreed with and violated all the time. One might say the only distinction is that one is not written down, while the other is. However, that is not the case. Because the law is the Natural Law written down.
Feelings are Natural Law. In fact, at a group level, Natural Law can be defined as “feelings agreed upon.” Simple law does not exist without reason. In fact, its compelling justification is its reason. People voluntarily abide it because it has a reason. Without reason, its only compelling case is coercion. Coercion can occur with or without a writing.
So, where it is stipulated that law exists, it can be stipulated that it only exists for those who recognize it and agree with the reasons that are used to justify its value. If there is a conflict between Natural Law (one’s feelings about good, bad, right, wrong, justice) and the law, then the law does not exist because it has no valuable justification or reason. Bob’s clan can say Sam’s clan has laws, but they aren’t Bob’s clan’s laws. They don’t exist for Bob’s clan.
I think a fundamental mistake in reasoning comes from a misunderstanding of what Natural Law is. I glean this from your OP: “O.W. Holmes, Jr. is considered to be one of the proponents of what's been called American Legal Realism, which is similar to legal positivism in its rejection of natural law theory and its
value-free approach to law.” [
Emphasis added ]. Natural Law most definitely is
not value-free. I don’t know where anyone got that idea, but they damn sure didn’t get it from the Founding Fathers or the Enlightenment. Nor is Natural Law objectively true or omnipotent or universally agree upon. To say it is, is to create a straw man, based upon an interpretation of Natural Law that is not correct.
Our Founding Fathers found a feeling they could not justify, so they called it a self-evident truth. Not only is their truth not true, physiologically or otherwise, but they then parsed the definition of “man” so they could get around slavery. Nevertheless, it is our
feeling that all men are created equal and it formed the justification, the reason, for all that followed. But all that followed was mere law.
The law does not provide the reason. Reason provides the law.
And reason is an effort to justify feelings about what is good, bad, right, wrong and just. These feelings spring from within. They don’t come from law. Feelings agreed upon are Natural Law, as far as the state is concerned.
Finally, there need not be any agreement for an individual man. The feelings are the “assumed standard” for those who feel them, and they are replete with value.