After reading moral philosophy for a while, you may come to suspect that being a moral philosopher must be utterly exhausting. Not just because reading and writing philosophy is hard work, but because it seems that even in their downtime philosophers are constantly having to perform complex feats of ethical calculation. Even worse, it seems that philosophers think life is like this for everyone else too – as if we’re forever running into decisions that demand we stop and compare our options against whichever moral principles we reflectively endorse. Only then, after performing these painstaking computations of right and wrong, duty and utility, can we act. It’s tiring just thinking about it.

The 20th century British philosopher Stephen Toulmin imagines a mundane scenario in which he has borrowed his friend’s book. The friend needs it back – should Toulmin give it to him? For Toulmin, answering this question will involve appeal to a series of increasingly universal principles about the rightness of promise-keeping. Reading this passage, K.E. Løgstrup, a Danish philosopher of similar vintage, found Toulmin’s flight into abstraction to be a repudiation of moral life rather than a description of it. To do the right thing in this situation, we don’t need to know about the universalisability of maxims about keeping our word. All we need to know is that our friend needs his book back.

Similarly, Bernard Williams imagines someone who chooses to save his drowning wife instead of a stranger. Moral theory might insist we should act impartially, yet trying to come up with reasons to justify this man’s choice to rescue his wife is to think “one thought too many”.

We can go even further. Sometimes actions are more morally praiseworthy the more thoughtless they are. We’d think more highly of someone who rushes into a burning building to save those inside than someone who hesitates just long enough to double-check that this really is the right thing to do. Yet how can a thoughtless action be a fitting, let alone praiseworthy, response to a situation?

One way to answer this is to examine what’s happening in our heads when we’re engaged in moral action. Very little of it involves thinking through abstract principles. Most of the time, we simply see what must be done. (That’s true even when we don’t then go ahead and do it.) We see the suffering in the face of an injured person, and we stop to help them. We see a wallet fall silently out of someone’s pocket and we call out immediately to warn them. We don’t deliberate, at least not consciously.

In recent years, there’s been renewed attention to the idea that we perceive the morally important features of a situation, rather than working them out reflectively or by applying principles or theories. Unsurprisingly, this view is known as moral perceptualism. Equally unsurprising, it’s quite controversial.

Moral perceptualism has a number of things going for it. Preston J. Werner has recently identified at least three main advantages: it fits the way perceptions seem important to forming moral judgments, the role that sensitivity to the relevant features of a situation plays in moral wisdom, and the way in which we actually experience most, though by no means all, of our moral lives. We’re struck instantly by morally compelling features of the world around us (“That’s cruel!”) just as we are when we perceive other properties (“It’s cold!”).

The worrying thing here is that to perceive something, it must, somehow, be out there in reality. If I sense that it’s cold, I’m perceiving a real property of the world, namely temperature. But what am I perceiving when I see that something is wrong? Some philosophers take properties like “good” to be non-natural properties of the world; G.E. Moore is probably the most famous modern example. Yet there’s something troubling about the idea that properties like ‘good’ and ‘ought’ exist independently of our minds.

You and I look at the same painting. I find it pretty and uplifting, you find it tacky and sentimental. After fruitlessly trying to talk each other around to our way of seeing the painting, we reluctantly agree that while we’re looking at the same shapes and colours, these other properties we’re attributing to the painting are not in the canvas, but in our heads. The suspicion is that moral properties like right and wrong might be like this too: not features of the world itself, but of our responses to it.

A famous version of this claim comes from the 18th century Scottish sceptic David Hume. Consider, for instance, an act of wilful murder. You may notice the passions, motives, and sufferings of the parties involved, but you cannot see the wrongness of murder as a property of these things: “You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. Here is a matter of fact; but ‘tis the object of feeling, not of reason. It lies in yourself, not in the object.”

Yet Hume, a bit like Toulmin, is to a certain extent dragging us away from our everyday moral experience rather than illuminating it. That experience, as we’ve seen, is one in which, more often than not, we make moral assessments instantly, in a way that feels more like perception than inference. We might come to believe on reflection that those initial judgments are wrong, or we might suddenly come to see things differently – but then, we do that with non-moral perceptions too. (I see the Queen walking around my local supermarket. I’m struck by the thought that the Queen is quite unlikely to be shopping here. I look again and see that on closer inspection it is not Elizabeth II grabbing some fish fingers out of the frozen food aisle, but a woman who looks similar.)

But moral perception is not, contra Hume, simply a matter of feeling disapproval of the things happening in front of us. It is also a matter of seeing details as relevant. You and I sit in class and listen as our teacher responds to something our fellow student has just said. I hear nothing exceptionable in the teacher’s words. You, however, hear all the subtle, deniable, but deliberate barbs and humiliations, and feel the stab as they’re delivered. You and I hear the same sentences being spoken, but there are dimensions of the situation that you’re attuned to while I remain oblivious. Nor are you simply adding feelings of distaste to what’s being said. To see a humiliation happening is already to make an evaluative judgment that, all else being equal, what is happening is wrong. (Perhaps there are cases where humiliating someone is justified by some wider context, but humiliation per se wears its badness on its face.)

Philosophers like to think. We like to interrogate concepts and perform complex logical analyses. So it’s understandable that we often assume everyday experience to be more reflectively taxing than it really is. But the attractiveness of moral perceptualism suggests much of our life just isn’t like that. We don’t walk around obsessively computing principles and maxims. We just see how things are. What we do next is the real test.

From the Perception edition.