Does anyone own "The Moral Landscape"?

[The Grand Nudger]

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Despite the broadly held perception that it does, ethics has nothing to do with subjectivity, cultural or otherwise.
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Incorrect.

From Wikipedia:

Subjectivity is a central philosophical concept, related to consciousness, agency, personhood, reality, and truth, which has been variously defined by sources. Three common definitions include that subjectivity is the quality or condition of:

1. Something being a subject, narrowly meaning an individual who possesses conscious experiences, such as perspectives, feelings, beliefs, and desires.
2. Something being a subject, broadly meaning an entity that has agency, meaning that it acts upon or wields power over some other entity (an object).
3. Some information, idea, situation, or physical thing considered true only from the perspective of a subject or subjects.

In ethics, "consciousness, agency, personhood, reality, and truth" are assumed even though they are arguably emergent/virtual/illusory/relational/axiomatic.

I should not speak for Rob but I suspect that he would agree with me that 1. and 2. are part of the ethics-equation but 'multi-subject' would be perhaps a more relevant term.

The word 'only' in part 3., makes it irrelevant to ethics.  If that is the position for which you think Rob and I have been arguing ... that would be a misreading.

 Reading three is the only reading relevant to what is actually meant by the term "moral subjectivity", lol.  The other two readings are irrelevant to the contention.  

When ethicists or moral philosophers ask themselves whether some moral statement is meaningfully objective, or meaningfully subjective..that is the question they are asking, and seeking to answer.  If you are not arguing for that, you are mistaken in the notion that you are arguing for moral subjectivity, or against moral objectivity.

Consider three sets of moral statements.

Subjective moral statements, statements that fundamentally -cannot- be true or false. Attempted objective moral statements that are demonstrably false, and attempted objective moral statements that are demonstrably true. Only category one is "subjective morality". Categories two and three...despite one being (purportedly) accurate and the other not..and despite whatever disagreement there might be between them, are the objective candidates.

The vast majority of objections to objective moral theory (as well as affirmations of subjective moral theory) are misunderstandings of the entire field of play. If a person refers to their privately held opinion as the cause of some thing x being right or wrong, they have ruled themselves out as an advocate for a moral fact. If a person refers to some thing contended to be true, independant of their privately held opinion..they are a candidate for advocacy of a moral fact...but they might still be wrong. Only when a person refers to some thing that -is- true, and -is- independent of their privately held opinion..are we dealing with a credible advocate for a moral fact.