[User23]

> What is insufficient about it?

Your opinion isn’t a valid ethical premise. It has no basis beyond your whims. Someone else might believe that it’s good and how would you refute them without claiming that your opinion is somehow more authoritative?

> Even if so can the aggressor and wider society know that ahead of time?

Obviously, in general, no. You can’t know that shooting a random person in cold blood wouldn’t prevent some greater evil. You can’t know that the child of that rape won’t cure cancer. The limitations of human reasoning are one of the reasons I’m convinced a correct ethics must have a superhuman author.

> The rule to avoid harming others is the least imposing value of all.

Once again this is begging the question. You’re trying to slip in the premise that minimal imposition is moral without any basis.

> After 30y of "living by faith" I'm no longer a fan of trusting in authorities just because their rules are old or their existence is unfalsifiable.

This betrays philosophical immaturity, which is of course fine. Most religious organizations do a very poor job with that aspect of formation, likely because those teaching are themselves philosophically immature. But this discussion isn’t about religion, faith, or your subjective experiences, it’s about whether the normative science of ethics can have any nontrivial conclusions without an objective foundation. If your anti-theism clouds your reasoning, feel free to instead pretend that we live in an advanced simulation and its authors defined human life as having inherent dignity. In that scenario ethics has a firm foundation. Now imagine the same scenario but without such a definition.

[paulryanrogers]

> But this discussion ... it’s about whether the normative science of ethics can have any nontrivial conclusions without an objective foundation

What is a more objective foundation than independently verified, experimental evidence?

> The limitations of human reasoning are one of the reasons I’m convinced a correct ethics must have a superhuman author.

So the apparent presence of this limitation is evidence of a higher power? How can you be sure that what you consider 'correct' ethics is objectively good?

[User23]

> What is a more objective foundation than independently verified, experimental evidence.

This sounds like the classic is-ought problem. Experiment can, up to epistemological and ontological limits, only tell us about what is. It cannot tell us about what ought to be. If it appears to you that it can then you’re implicitly slipping in an additional ethical premise.

> So the apparent presence of this limitation is evidence of a higher power? How can you be sure that what you consider 'correct' ethics is objectively good?

I can’t. That’s one of the limitations of abductive reasoning. Unlike deduction it cannot reach absolutely certain conclusions. And if I could this entire thread would be moot. As for correct ethics, I accept Peirce’s view that ethics, like logic, is a normative science. Just as logic is defined to be the normative science of what is true or false, ethics is defined to be the normative science of what is good or bad. Hence my question about whether or not that science is trivial and admits whatever conclusions anyone says it does, or not.

[dragonwriter]

> Your opinion isn’t a valid ethical premise.

Then there are no valid ethical premises, because all value propositions necessarily either are directly or rest upon subjective preference.

[User23]

> all value propositions necessarily either are directly or rest upon subjective preference

You haven't shown this, so you're just sneaking in the premise that ethics has no objective foundation, which is the very question under consideration. I could just as easily baldly assert "all value propositions necessarily either are directly or rest upon objective foundations," but I'm not because it would be philosophically uninteresting.

I accept that there are no valid ethical premises is a valid conclusion from the absence of an objective ethical authority. I can only abductively conclude the existence of such an authority because it appears to me that ethics is not in fact a degenerate science that can produce any result whatsoever.