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Whether morality is an objective property of the universe, or instead the subjective opinion of humans, is one of the longest running issues in philosophy. Jerry Coyne recently returned to the theme, arguing that morality was subjective, and, as I usually am, I was surprised by the number of commentators arguing the contrary.

This debate seems hampered by a lack of clarity on what “objective” and “subjective” moralities are. Coyne gave a sensible definition of “objective” morality as being the stance that something can be discerned to be “morally wrong” through reasoning about facts about the world, rather than by reference to human opinion.

If morality were objective, it would have to be conceivable that the statement “George’s actions were wrong and he deserves to be punished” would be true even if every human in the world were of the opinion, “George’s actions seem fine to me, perhaps even laudable”.

Thus, if morality were an absolute set by a god, something could be immoral even if every human disagreed. If, instead, human feelings and desires are what ultimately count, then that is a subjective morality.

Thus, a subjective morality is strongly preferable to an objective one! That’s because, by definition, it is about what we humans want. Would we prefer to be told by some third party what we should do, even if it is directly contrary to our own deeply held sense of morality?

Given that an objective morality would be highly undesirable, why do so many philosophers and others continue to try hard to rescue an objective morality?

I suspect that they’re actually trying to attain objective backing for what is merely their own subjective opinion of what is moral. This is the trick the religious have long played, inventing a god in their own image who can back them up by turning “I want …” into “God wants …”.

Secular philosophers should not play this game by hankering after objective morality, we should have confidence in the simple and honest “I want …”. We humans have a lot to be proud of: by thinking it through and arguing amongst ourselves, we have advanced morality hugely, with Western society today giving vastly better treatment to individuals, to women, children, religious minorities, foreigners, those of other races, the disabled and mentally ill, criminals, etc, than any previous society.

So why are we all so afraid of admitting that, yes, morality is subjective? I suggest that this owes to several misconceptions.

Subjective does not mean unimportant. A subjective morality is one rooted in human feelings and desires. These are the things that are most important to us, indeed the only things important to us!

Subjective does not mean arbitrary. Human feelings are not arbitrary. It is not arbitrary that we love our children while most of us dislike and fear spiders and snakes, nor that most of us like the taste of chocolate while shunning excrement. Our feelings and attitudes are rooted in human nature, being a product of our evolutionary heritage, programmed by genes. None of that is arbitrary.

Subjective does not mean that anyone’s opinion is “just as good”. Most humans are in broad agreement on almost all of the basics of morality. After all “people are the same wherever you go”. Most law codes overlap strongly, such that we can readily live in a foreign country with only minor adjustment for local customs. A psychopathic child killer’s opinion is not regarded as “just as good” by most of us, and if we decide morality by a broad consensus — and that, after all, is how we do decide morality — then we arrive at strong communal moral codes.

But still people hanker after “objectivity”, and worry that a subjectively decided communal morality is somehow insufficient. Here, then, are six reasons why the whole notion of “objective” morality is nonsense.

(1) Our morality is evolved.

Nothing in biology makes sense except in the light of evolution, said Dobzhansky, and morality certainly makes no sense except as the product of our evolutionary heritage. Our moral sense is one of a number of systems developed by evolution to do a job: the immune systems counters infection, the visual system gives us information about the world, and our moral feelings are there as a social glue to enable us to cooperate with other humans.

As a product of blind Darwinian evolution, our morals will have developed solely from the pragmatic consideration of what works, what enables us to benefit from cooperation and thus leave more descendants. For interacting with another human, what matters is not what is “objectively” moral (whatever that means), but what that human considers to be moral.

Human intuition that morality is objective is really the only argument (if we are honest) that that is the case. And yet evolution doesn’t operate according to what “is moral”, it operates according to what helps someone to have more descendants. Thus, even if there were an “absolute” morality, there is no reason to suppose that it would have any connection to our own human sense of morality. Anyone arguing for objective morality by starting with human morality and intuition — which of course is how it is always done — is thus basing their case on a non sequitur.

(2) Humans are only one species.

An objective morality must, by definition, be independent of human opinion and thus be independent of humans. There are trillions of galaxies in the known universe, each with trillions of stars and trillions of planets, and for all we know there may be millions of species on many of those planets.

And yet, surprise surprise, the “objective” moral systems that people argue for are all about human welfare and just happen to bear a striking resemblance to the morals of that one species of ape on just one planet around a fairly unremarkable star in a fairly unremarkable galaxy. This is simply projection, human hubris.

Medieval theologians placed humans at the centre of the universe; aren’t we above projecting our own parochial notions of social interactions into some sort of objective property of the universe? Isn’t it obvious that our social interactions (and thus our moral senses) will depend on the details of our species and our ecological niche?

A K-selected species would have very different morality from an r-selected species. A haplodiploid or eusocial species would have very different morality from us. So would species where hareems are normal. Morality would be very different in territorial animals than in non-territorial animals. And who knows what variations there are strewn across the trillions of galaxies in the visible universe? And yet people want to consider one species alone from one planet alone and project that onto everything else!

Editor's Note: The r/K selection dichotomy mentioned here is actually false. It's also worth noting that this argument implies that different human races could have different conceptions of morality.

(3) Starting from “well being” is subjective.

Many attempts at establishing an objective morality try to argue from considerations of human well-being. OK, but who decided that human well-being is what is important? We did! This whole enterprise starts with a subjective leap. Yes, human well-being is what morality is all about but human well-being is all about human feelings and preferences, and is thus subjective.

(4) Aggregation schemes are arbitrary.

So you’ve decided that well-being is what matters. Good start. But, if you want to arrive at an objective morality you now need a scheme for aggregating the well-beings of many creatures onto some objective scale, such that you can read off what you “should” do and how you “should” balance the competing interests of different people.

The beauty of accepting that morality is ultimately subjective is that you reject the whole concept of objective aggregation onto an absolute scale, and thus an otherwise insoluble problem disappears.

(see the rest of the post in the link)