Does Objective Morality Exist? What The Stoics Knew That We’ve Forgotten
Written by Tanner O. Campbell, Philosopher of Stoicism
Tanner Campbell is a public philosopher specialising in orthodox Stoicism. He hosts the Practical Stoicism podcast, co-authored "What Is Stoicism? A Brief and Accessible Overview", and runs a private Stoic coaching practice in Dundee, Scotland.
Take away God, and most people will tell you that morality becomes a matter of taste, that whatever we call right or wrong belongs to whoever happens to be doing the calling. The Stoics disagreed, and they built their case on nothing more supernatural than what a human being is. I think their argument still holds up, and I want to walk you through the whole of it, right up to the strongest objection anyone has raised against it.
Take away God, and most people will tell you that morality becomes a matter of taste, that whatever we call right or wrong belongs to whoever happens to be doing the calling. The Stoics disagreed, and they built their case on nothing more supernatural than what a human being is. I think their argument still holds up, and I want to walk you through the whole of it, right up to the strongest objection anyone has raised against it.
Why is "good" such a slippery word?
Most of us use the word "good" in at least three common ways, as a preferred experience ("it would be good to go to the beach today"), as enjoyability ("we enjoyed that movie, it was good"), and as an aesthetic ("that's good interior design").
None of these uses captures what we mean when we say "he is a good man" or "she is a good woman". The goodness of a person, or of peace, charity, kindness, or virtue, is a different sort of thing entirely, and yet common use has functionally de-specialised the word. It now has the same problem the word "theory" does.
In everyday speech, a theory is little more than a guess ("we have a theory about why Beau didn't come to breakfast"), while in science, a theory is an explanation supported by evidence that is capable of accounting for a body of observed facts, which is no kind of guess at all.
Good once had a specific definition too, and we have all but forgotten it.
How did the Greeks measure goodness?
Ancient Greek philosophy gives us a much more precise way of thinking about goodness, a thing can be judged good according to how well it fulfills the function proper to the kind of thing it is. Goodness, in this sense, is a measure of excellence against a standard.
Plato runs a version of this argument with eyes and pruning knives in the Republic [352e to 354a], and the Stoics built their account of the human Good on the same foundation, using the word agathon for what is genuinely Good and ultimately identifying that Good with virtue.
We say a carving knife is a good carving knife if it carves well, because carving well is what a carving knife is designed to do, and we say an eye is a good eye if it sees well, because seeing well is what an eye evolved to do.
With this understanding of good in hand, there is nothing subjective about saying that a blind animal has bad eyes, or that a chipped carving knife is a bad carving knife. (This does not, of course, make the blind animal a bad animal. We have judged its eyes against the function proper to eyes, not the animal as a whole.)
Now let's make the jump from organs and objects to entire animals.
What makes a honeybee a good honeybee?
The question feels much harder to answer, but it isn't, because we already know the answer has to relate to the natural functions of a honeybee. We ask what Nature compels a honeybee to do, and whether the honeybee in question does those things well.
If it does, it's a good honeybee. If it doesn't, it's a bad one.
What is a good human being?
The same move works on us, but first we have to know what our natural functions are. The Stoics held that humans are rational and social animals. Reason is our distinctive governing capacity, the thing that separates us from animals governed by impressions and impulses, and our social nature matters just as much because we are creatures who reason and who live among, cooperate with, and have obligations toward other human beings.
This is why the Stoics defined the goal of life as living in agreement with nature,[1] and why Marcus Aurelius kept reminding himself to do what his constitution required of him.[2]
So a good human being is one whose rational and social capacities function well.
But this cannot simply mean being clever, because a person can reason very effectively toward a vicious end, and history is a catalogue of exactly that.
For the Stoics, reasoning well means reasoning correctly, which is to say bringing our judgements, choices, and actions into accordance with reason and with our social nature. The perfected condition of that nature is what they called virtue.
In practice, this means learning to see things as they are rather than as they might seem through the filter of our bodily and emotional responses.
Imagine a friend jumps out and scares you as a prank. You feel the fear before you are capable of making any judgement about what is happening, and only once your rational faculty has had a few seconds to come online do you understand that there is nothing to be scared of at all, even though the body's residue, the racing heart and the adrenaline, may hang around for a good while afterwards.
A person who can see the world as it is, who is not misled by private biases, elations, assumptions, and fears, is a person functioning well as a human being.
None of this means that good humans feel no emotion, only that they understand emotions to be something of a narrative medium, and that the stories the medium tells, while compelling and revealing of something real, are very rarely true.
Is any of this actually objective?
Consider mathematics for a moment. Plus signs, numbers, the term "quadratic equation," all of these are human inventions, and that might lead someone to call mathematics subjective. They would be only kind of right, because the phenomena those invented symbols describe, predict, and manipulate objectively exist.
You can have one thing, place another of the same thing beside it, and suddenly have two of those things. The word one, the symbol 1, and the formal concept of addition are human constructs, but they describe something objective, and this is why 1 × 3 = 12 is objectively incorrect rather than merely a matter of opinion.
A moral system works the same way. It does not require moral terminology to exist independently of human beings, what it requires is that it describe objective phenomena accurately and that it provide a framework against which claims can be tested.
Within Stoic philosophy, a morally good choice is one that maintains fidelity with the framework, while a morally bad choice is one that betrays it, and whether a given choice does or does not maintain that fidelity is not a matter of personal opinion. It is something that can, at least in principle, be assessed objectively.
But isn't the framework itself subjective?
"You're just shifting the goalposts," you might say. "Something is objective if it adheres objectively to a moral framework, fine, but that leaves the morality of the framework itself. That's still subjective!"
You're absolutely right.
So the question becomes whether the framework corresponds with something objective, such that the framework itself can be assessed, and this is where Stoic physics comes in.
The Stoics held that reality is wholly physical, and that the cosmos is matter structured and animated by an active rational principle, something we can think of today as immutable law, such as entropy, the laws of motion, or gravity.
The universe, on their account, is not a collection of unrelated things but a single, causally ordered whole, and we are part of that structure.
Human reason is not something separate from Nature but one expression of the same rational principle that structures the cosmos, which means we are not blank slates inventing values and imposing them on an otherwise meaningless world.
We are a particular kind of thing with an objectively describable nature, rational, social, embodied animals, and that nature is where the moral framework gets its standard.
Virtue, in other words, is not good because the Stoics happened to like it, nor because a god issued a command requiring it. It is good because it describes the excellent functioning of the kind of thing a human being objectively is.
The structure looks like this, objective reality gives us an objective human nature, objective human nature gives us a standard of human excellence, and that standard lets us assess whether our reasoning and conduct are functioning well or poorly, and those assessments are not merely matters of taste.
What about Hume's guillotine?
I made a version of this argument on LinkedIn recently, and a fellow philosopher raised the objection this argument commonly meets. I want to share it here because the exchange sharpened my own thinking, and it might sharpen yours as well.
The objection comes from David Hume,[3] and it says that you cannot derive an ought from an is.
On this reading, my argument smuggles in a hidden value judgement, elevating one type of human behaviour as intrinsically human while denigrating the rest. And how do we determine what human nature is, other than by looking at humans? Which humans get to be the models? Without an objective answer to that question, the objection goes, we are back in the land of the subjective.
My response was, and remains, that the argument does not depend on choosing model humans at all.
Human nature, as I have used it here, means the objective capacities constitutive of the kind of organism a human being is, not whatever behaviours humans happen to exhibit. Rationality and sociality are constitutive human functions in the same way sight is constitutive of an eye, and just as a blind eye is still an eye (only one that is not functioning well), a human being can remain fully human while reasoning and acting badly.
The word "human" is a convention, but the organism and its capacities are not, in the same way the word "oxygen" is invented while oxygen itself is not.
Nor is the "should" hidden anywhere. The evaluative premise is stated openly, goodness consists in fulfilling the standard proper to the kind of thing something is.
You can, of course, reject that premise (plenty of people have, and plenty more will), but then your disagreement is with Stoic naturalism itself, and simply calling the standard subjective does not establish that it is. That, after all, is the very claim we would be disputing.
Where does this leave us?
If being a good human means functioning well as a rational and social creature, then becoming good is a matter of training rather than of waiting for a rulebook to arrive, and nowhere does that training matter more than in people whose decisions land on other people.
This is the work I do as a private philosopher to executives and leaders, building the structured moral fabric this essay has been describing, a tested standard to reason from, so that the hundred decisions a leader makes in a week are made well rather than merely made fast.
If your judgment is the thing your organization runs on (and if you lead anything, it is), you can find me here or email me here.
Read more from Tanner O. Campbell
Tanner O. Campbell, Philosopher of Stoicism
Tanner Campbell is a public philosopher who teaches Stoicism as the ancient Stoics actually practised it, not in the way that pop culture has bastardised it. He hosts the award-winning Practical Stoicism podcast (over 10M downloads), and co-authored "What Is Stoicism? A Brief and Accessible Overview." Through his company, 134 Labs, he delivers decision-making and team workshops to businesses, mentors private clients one-on-one, and writes the Stoic Brekkie newsletter weekly. He writes the journaling curriculum at StoicJournaling.com, a year-long daily journaling programme. Tanner lives in Scotland with his wife and their son.
References:
[1] Diogenes Laertius, Lives of Eminent Philosophers, 7.87
[2] Meditations, 7.55
[3] A Treatise of Human Nature, 1739, Book 3
