I want to write at length today about Moral Relativism, or, somewhat more accurately, Meta-Ethical Subjective Relativism. In part, I'll describe this position. In part 2 I'll argue for its adoption, and in part 3 I'll discuss its consequences and implications.
Before I begin, I want to explicitly discard all the accumulated baggage about what other people have meant by "meta-ethical relativism" and other related terms. I don't want to ignore others' arguments; I just don't want to commit to their definitions. I'm a philosopher, and we're
If you want to critique someone else's philosophy, go do it on their blog. If, on the other hand, you want to shred my own work into little tiny pieces, be my guest. Be as salty as you like: I can dish it out, and I can take it too. I practice philosophy as a full-contact sport.
Let me first address three dichotomies that, through no fault of their own, have been dragged into the general philosophical confusion of the last couple of millennia: the relative/absolute dichotomy, the subjective/objective dichotomy, and the ethical/meta-ethical dichotomy. Again, I'm simply going to abandon the historic controversies about these terms and define them anew.
A statement, sentence, proposition, property, or any other describable quality or quantity is relative if and only if it, or statements about it, require additional context or information to ascertain a definite, singular evaluation. For example, an object's velocity is a relative property: According to the Good Doctor Einstein, I cannot assent to any definitive statement about an object's velocity without additional information: specifically a coordinate system from which I am to measure the object's velocity.
A sentence, etc, is absolute if no additional information is necessary to make a definitive, singular evaluation. For instance, an object's velocity-relative-to-coordinate-system-X is an absolute quantity, because I need no additional information to make or assent to a definitive, singular answer.
This appears to be a difficult concept for some people to wrap their heads around. It looks like a contradiction: How could velocity be both relative and absolute? But it's not a contradiction: "Velocity" is different from "velocity-relative-to-coordinate-system-X". A relative quantity can be turned into an absolute quantity by supplying what it's relative to.
Likewise too, the validity of mathematical statements are also relative to their axioms. The statement "2+2=1" is invalid relative to ordinary arithmetic, but valid according to modulo-3 arithmetic. Likewise the statement, "The sum of the interior angles of a triangle is always 180 degrees," is valid relative to the axioms of Euclidian geometry, but invalid according to the axioms of spherical geometry.
The relative/absolute distinction is deterministic and binary. Barring self-reference (a can of worms in its own right) a meaningful quality is either relative or absolute (binary) and you can determinable which one (deterministic).
I could perhaps spend a lot more time making the above considerably more rigorous, but if you keep the canonical example of velocity in mind, you won't go too far wrong.
"Subjective" refers to minds and their properties; "objective" refers to non-minded things and their properties. (Collect them both together and you have the "real").
I don't want to get sucked into recondite theories of consciousness: I mean by "minds" the ordinary prosaic intuitive things we think and speak of as our own and others' minds. Yes, to a scientific materialist such as myself, minds are abstract entities that can be reduced to complicated states of neurons and brain chemicals. Since neurons and brain chemicals are not minds, this would be objective sort of talk. So we can talk about people's minds in a subjective sense or their brains in an objective sense--no big deal.
Any time we're talking about people and their minds, we're talking subjectively: Alice believes that P, Bob approves of P, Carol likes P, Dave is happy, Enid is agitated, etc.
With allowances regarding the reduction noted above, the subjective/objective dualism is again binary and deterministic.
(When talking about ethics in relation to societies, cultures, religions, and the like, one has to be careful about the fallacy of reification. Societies, etc. do not have minds; they are not subjective entities per se. Since societies are collections of people, we can talk subjectively about the people who comprise those societies. In other words, "The good of society," is meaningless unless it is metaphorically understood as, "The good of some or all people in the society.")
Statements of ethics are again those ordinary, prosaic statements we normally consider to have ethical content: statements which use "should", "shouldn't", "right", "wrong", "approve of", "disapprove of", etc. (The dichotomy between ethics-statements and non-ethics-statements is somewhat fuzzy; I doubt that many would consider the statement, "If we drive 90 MPH, we should make it to Chicago in two hours," to have ethical content. This fuzziness doesn't present much of a problem, though; we can restrict our consideration to the large class of statements with uncontroversial ethical content, at least at first.)
Statements of meta-ethics, on the other hand, are statements about ethics-statements.
This is an important distinction because we're going to find there are a lot of characteristics that hold for meta-ethics-statements that don't hold for ethics-statements.
What Meta-Ethical Subjective Relativism Is
If we put all these together, we get meta-ethical subjective relativism:
Statements about ethics have an absolute truth-value if and only if they are stated relative to some subjective entity or property.
"Killing people for fun is wrong," has no truth-value. "The Barefoot Bum violently disapproves of killing people for fun." does have truth-value (as is in fact true).
What Meta-Ethical Subjective Relativism Isn't
MESR is not ethical subjective, cultural or societal relativism. Ethical subjective relativism (as often described) entails that if Alice approves of X, then "X is good" is true. But if Bob disapproves of X, then "X is good" is false. This contradiction is pretty obvious; a bright twelve-year-old can confidently dismiss this conception.
Substitute societies for people, "knows that" for "approves of" or any suchlike, and it's still contradictory.
MESR does not entail any sort of epistemic, ontological or truth relativism. MESR is not, "True for you, false for me;" it's, "True of you, false of me." Since you and I are different people, we can have different properties without contradiction.
MESR does not require proof that meta-ethical objectivism or objective relativism is false. MESR can be held skeptically; if some genius were to actually justify an objectivist theory then I would change my mind. We are, however, entitled to wait on such a proof. (More on this in part 2.)
MESR does not deny ethical absolutes or entail moral nihilism. It states, rather, what an ethics-statement must be stated relative to (i.e. a subjective entity or property) to make it absolute and have an actual truth-value.
MESR does not entail that all moral beliefs are the same. It entails only that all moral beliefs are objectively (i.e. not relative to any subjective entity) non-truth-apt. I'll explore this aspect more in part 3.
MESR does not entail that you should have any particular moral beliefs, any moral beliefs, nor no moral beliefs. MESR treats individuals' subjective beliefs as facts.
MESR does not entail that moral beliefs are entirely outside the domain of reason. There are good pragmatic reasons (which I'll explore in part 3) why it's useful to rationalize your moral beliefs, and why it's useful to make moral distinctions on the basis of objectively true distinctions.
MESR neither entails nor depends upon the absence of human-universal or near-universal moral beliefs.
 As near as I can determine; philosophical terminology tends to accumulate like Republicans on a Defense contract. Also note that I use "moral" and "ethical" as synonyms. People inveigh against "moral relativism", but "meta-ethical" sounds better than "meta-moral".
Don't blame me for this confusion; I didn't spend the last two thousand years screwing up the language trying to prove the existence of God.
If any reader can convince me to use different terminology, its implementation is only a global search-and-replace away.
 Yes, I'm (more or less) a nominalist (with, of course the proviso that I don't necessarily buy into everything that anyone's ever said about nominalism); hardly surprising for a professional engineer. Most of what I say about statements maps well to propositions, though.
 Except the velocity of light in a vacuum, which is the same in all coordinate systems, and thus absolute.
 If one is going to be