Stephen,

> the concept of (a?; the?) “natural law” is just too vague and amorphous to serve as the ethic of justice, i.e., the ethic for governing the governance of society <

I don’t think it’s sage or amorphous, but it is general. It isn’t supposed to dictate specific positive laws, but to provide a framework for our ethical behavior.

For instance, according to natural law it is not right to murder people, or to steal, because both behaviors undermine individual flourishing and destabilize the social group. Nothing vague about that!

> “observation” does point the way to a valid ethic of justice <

Right, in the sense that we observe human behaviors, learn more about human nature, and think about how we can build societies that allow animals like us to thrive.

> that boils down to a handful of absolute prohibitions: no killing, harming, coercing, stealing, or manipulating (lying, cheating, etc.) in effecting any choice. <

Not sure about the “any choice” bit. There are choices we may make that negatively affect others, and would therefore not be just. For instance the “personal” choice not to get vaccinated during a pandemic.