What would happen if one morning you wake up clumsy, as if your sense of touch were unreliable, arbitrarily on and off? Perhaps you go to the kitchen to make your morning coffee but break the coffee pot because you lifted it up as if it was made of stone. As a consequence you hit it with another object and it broke. But wait: you pick up a shard of glass and don't feel the sharp edge. Now you have cut yourself but for some reason it doesn't hurt. Yet you don't feel like leaving a trail of blood this morning so you clean the wound and put on a bandage. You still desperately need coffee, so now you have to make it on the stove top. You grab a small pan (this time no accident happens, but your movements are not exactly smooth) and put it under the faucet. As the water fills up the pan and increases the weight, you can't hold it and end up spilling the water. You try again, but this time – who knows why – there are no problems at all and it all goes as normal. Now you heat up the water. Everything is fine, except that you burn yourself. You don't feel the heat, so nothing reminds you to grab the potholder. So clumsy! Now you have to deal with that burn. And still, all of a sudden, it starts to hurt – and it really does! Argh! Let us leave our 20 clumsy morning minutes here: broken coffee pot and you are now cut, burned and without coffee!

Now, what would happen if one Wednesday, watching the evening news while your 9-year old boy and 12-year old girl are around, you happen to be morally clumsy? Morally clumsy? Yes. Say you are watching the news and there is coverage of a memorial event for Holocaust victims. You want to teach something to your children, so you remark that around six million Jews were killed in World War II and emphasize how tragic it was. The next story talks about the drought in the horn of Africa in 2011, where 12 million people are starving, and around 3 million in high risk of dying due to starvation. Children die every day, and images of terribly emaciated kids are shown. This time you don't say a word. Your 9-year old wonders why those kids there, who are the same age as him and are suffering, do not get a word from you. After all, if nothing is done hundreds of thousands will very likely die, and you had just said that the Holocaust was terrible … he doesn't understand.

Soon after, that same night, there is a story about the shooting in Oslo, Norway, in July 2011. You are morally outraged: ‘How horrible! 91 people killed by a crazy guy!’ Your 12-year old girl wonders why, the other night, while they were showing a story about killings in the Democratic Republic of Congo with numbers perhaps worse than those of Oslo, you got up to get a beer, making sure to be back by the time sports were on. Your daughter is now baffled: why is it so sad and terrible in Norway, and it is not in the Congo? She thinks it might have been better if you had never said anything: she thinks you set up a standard you're not living up to. She is not thinking very highly of you right now. Let's leave our Wednesday evening behind. This time no jars broken, no cuts, not burns, plenty of beer and, if it were not because you had company, there would be no big traces of your moral clumsiness.

So here is my point. I want to expound an interesting analogy between the sense of touch, loosely construed, and the moral sense; and with that, the specific message I want to convey is that just as a sort of consistency is necessary for the sense of touch to do its job, so it is for the moral sense. Following the analogy, I will suggest that inconsistency causes, in both cases, a certain clumsiness.

First, let me say a couple words about my use of ‘the sense of touch,’ which I mean here in a loose way, which is how we use it in everyday life. In technical terms there is a distinction between the more precise ‘touch’ and the somatosensory system. ‘Touch’ enables us to feel size, texture and shape by the skin. The somatosensory system includes the sense of touch, as well as the abilities to feel our own bodies (i.e. the position of our limbs and their interaction with objects), to feel pain or itch, and to feel temperature. For example, this ‘sensory mix’ allows us to feel the weight and hardness of objects, which are properties that we would say we experience by touch. It is this sensory mix which we normally refer to as touch. This explains what the job of the sense of touch is, because literally, it is to keep us in touch with the world.

Second, notice that feeling through the sense of touch involves a feedback loop. We know the world and we act accordingly. For example: we have a pretty good sense of how resistant a given piece glass is, or how delicate a baby's hands are. But this is just an initial clue, on top of which we finely tune our actions to what we specifically feel at the moment. It is like that pot that the clumsy morning coffee maker was trying to fill up with water: we grab a pot whose weight is known to us, with a force appropriate to that weight. When we put it under the water faucet and its weight increases, we adjust accordingly the force we use. This is indeed a very basic thing, and we ‘know’ it all too well – that's why it sounds a bit silly that I say it here! But notice, however, that this feedback loop effect applies to all things touchable. In fact, we can generalize and say that we feel the world through a sort of constant contact with it.

Now, what is the job of the moral sense? The moral sense constitutes our moral perspective in life. In this sense, it is not so much a compass – simply indicating ‘the right thing to do’, as it were – as it is a lens through which we see all things moral. In other words, it is literally a moral sensibility: it determines what we feel and how we feel it and how we react to it. It comes into play when we act or when we judge our actions and those of others.

Judgments and actions are, thus, the expression of a person's morality – they express who we morally are. There is a crucial element that I must now clarify, and I beg the reader to go a bit more slowly through this paragraph. The reality of the physical world depends on the physical world itself. This means that it is the weight of objects that dictates the force we use to lift them up, and not our force that dictates how heavy objects are. In contrast, the reality of the moral world depends on the way we – as individuals, but also as societies with traditions, conventions and value systems – judge and act towards situations and behaviors. This means that it is our actions and judgments that dictate the moral weight of situations, and not any supposedly ‘objective moral weight’ that dictates what we should do and the judgments we should pass on situations.

Because of social conventions and their endurance, it is natural to think that moral situations are objectively right or wrong, morally heavy or light. However, this is only an impression. The consistency and stability that we find in our dealings with things moral come from us, as individuals and as societies. It does not lie in things or situations out there, in the way weight is related to matter, but in our interactions with them. Although moral consistency and stability are not objective, they are not merely subjective either. They are indeed at the very heart of morality.

In sum, I am trying to show that some sort of consistency is necessary for both the sense of touch and the moral sense to do their job. I explained what the tasks of the sense of touch and of the moral sense are, and, in order to avoid important misunderstandings, I made a distinction regarding physical reality and moral reality. Now I can tackle my main point: why is consistency necessary?

In the case of the sense of touch – provided our trust that the physical world is not suddenly going to change – we need to be able to rely on our capacities in order to feel the world. We need to be in touch with the world. Your kitchen will not randomly change in the morning, but if you do not have a sense of touch that allows you to reliably feel things around, you won't be able to make your morning coffee (and coffee-making is only the tip of the iceberg!). The reason is that you won't be able to feel and compare the weight, hardness, temperature or texture of objects, and won't be able to act on that basis. Not even trial and error would be possible – and yes, you would quite likely cut and burn yourself!

In the case of the moral sense, to lack consistency would mean, analogously, that we would be unable to rely on our judgments about different moral situations. The same moral situation would be judged one day in one way and another day in a different way. Our criteria would not really be criteria, but mere occurrences or caprices. The very idea of making moral judgments would start to fracture if we were unable to see any likeness between things. Moreover, we would act or react in arbitrary ways. This is exactly the danger lurking in the lack of consistency or moral clumsiness: moral arbitrariness.

The risk is arbitrariness, and it is not far from inconsistency. Moral arbitrariness is a contradiction in the terms. A morality that is arbitrary is not morality. But any ‘morality’, however, depends from identifying features that could be present in more than one situation, that is, from some likeness. Thus, likeness underlies consistency. Given all this, does it not follow that thinking of ourselves as actually ‘having’ morality partly entails that we use, as a matter of fact, some consistency? And doesn't this mean, too, that who we morally are, for ourselves and others, depends also on ourselves being more or less consistent?

Let me make an important clarification: consistency is not sufficient for morality, but it is necessary. We know that consistency is not sufficient for morality when we imagine a person acting consistently on the basis of radically wrong principles, such as despising every person and aiming to hurt everyone. We know consistency is necessary for morality when we imagine a person that helps others in dire need, but only does so on rainy days, or when she is wearing blue socks, or simply when she feels like it – that is, when a person acts based on acceptable principles but only in arbitrary circumstances.

Whatever criteria someone applies in the moral world is in itself a criterion of likeness or similarity. In moral matters this means having a criterion to decide what counts as worthy or despicable, as worth acting or as deserving indifference. Philosophers would say that a normative claim is based on an epistemic one. This means that we are somehow required to act similarly when we judge and act morally in similar cases, because we have the ability to identify similar moral features in different situations and act accordingly. If I lament the loss of human lives at 3 p.m., I should lament it at 9 a.m., and I should lament the losses of both people of my own racial or ethnic background and of those of other backgrounds. If I despise oppression, I should equally blame oppressors in World War II or in the Middle East or in South Africa or in prisons in my country.

With these examples I am not trying to say what your standards should be. My only intention is to say that moral standards ought to be applied consistently. If you happen to find yourself in the position of not treating like cases in like ways, then you should strive to change your ways and judge like cases alike. And if you don't know whether or not you are being consistent, then you should reflect on your judgments and actions, and try to be clear as to what features are they that you consider morally praiseworthy or blameworthy, and whether you judge and act accordingly. This is what it means to be morally consistent – as opposed to morally clumsy.