Unit 4: How One Should Live

Kantian Ethics

Andrew Fisher and Mark Dimmock

In spite of its horrifying title Kant’s Groundwork of the Metaphysic of Morals is one of the small books which are truly great; it has exercised on human thought an influence almost ludicrously disproportionate to its size.

– H. J. Paton, ‘Preface’ in I. Kant, Moral Law, p. 7.

An Introduction to Kantian Ethics

Immanuel Kant was born in 1724 in Königsberg in East Prussia, where he died in 1804. Kant is famous for revolutionising how we think about just about every aspect of the world — including science, art, ethics, religion, the self and reality. He is one of the most important thinkers of all time, which is even more remarkable by the fact that Kant is a truly awful writer. His sentences are full of technical language, are very long, and are incredibly dense. You have been warned!

Kant is a rationalist writing during the Enlightenment (1685–1815). He thinks that we can gain knowledge from our senses and through our rational capacities. This means his general philosophical approach starts by asking what we can know a priori. This is key to understanding his work but also makes his writing on ethics seem a bit odd. We think the study of ethics — unlike say maths — ought to direct our eye to what is going on around us in the world. Yet Kant starts by turning his eyes “inward” to thinking about ethical ideas.

Kant believes that in doing this people will come to recognize that certain actions are right and wrong irrespective of how we might feel and irrespective of any consequences. For Kant, actions are right if they respect what he calls the Categorical Imperative. For example, because lying fails to respect the Categorical Imperative it is wrong and is wrong irrespective of how we might feel about lying or what might happen if we did lie; it is actions that are right and wrong rather than consequences. This means that Kant’s theory is deontological rather than teleological. It focuses on our duties rather than our ends/goals/consequences.

There is, however, something intuitive about the idea that morality is based on reason rather than feelings or consequences. Consider my pet cat Spartan. He performs certain actions like scrabbling under bed covers, meowing at birds and chasing his tail. Now consider my daughter Beth, she performs certain actions like caring for her sister and helping the homeless.

Spartan’s actions are not moral whereas Beth’s actions are. Spartan’s thinking and actions are driven by his desires and inclination. He eats and plays and sleeps when he desires to do so, there is no reasoning on his part. Beth, in contrast, can reflect on the various reasons she has, reasons to care for her sister and the homeless.

We might think then that humans are moral beings not because we have certain desires but precisely because we are rational. We have an ability to “stand back” and consider what we are doing and why. Kant certainly thought so and he takes this insight as his starting point.

Some Key Ideas


Kant’s main works in ethics are his Metaphysics of Morals (1797) and the Groundwork of the Metaphysics of Morals (1785). Neither give practical advice about particular situations but rather through rational reflection, Kant seeks to establish the supreme principle of morality.

He starts from the notion of “duty” and although this is a rather old- fashioned term, the idea behind it should sound familiar. Imagine, your friend has told you that she is pregnant but asks you to promise to keep her secret. Through the coming weeks this juicy bit of gossip is on the tip of your tongue but you do not tell anyone because of your promise. There are things we recognize as being required of us irrespective of what we (really) desire to do. This is what Kant means by duty.

But this raises the question. If it is not desires that move us to do what is right (even really strong desires), what does? In our example, why is it that we keep our promise despite the strong desire to gossip? Kant’s answer is “the good will”.

Good Will

Kant gives the following characterization of the good will. It is something that is good irrespective of effects:

A good will is good not because of what it effects or accomplishes — because of its fitness for attaining some proposed end: it is good through its willing alone — that is, good in itself.[1]

It is also good without qualification.

It is impossible to conceive anything at all in the world, or even out of it, which can be taken as good without qualification, except a good will.[2]

What does Kant mean? Well, pick anything you like which you think might make an action good — for example, happiness, pleasure, courage, and then ask yourself if there are any situations you can think of where an action having those features makes those actions worse?

It seems there are. Imagine someone who is happy when kicking a cat; or someone taking pleasure in torture; or a serial killer whose courage allows her to abduct children in broad daylight. In such cases the happiness, pleasure and courage make the actions worse. Kant thinks we can repeat this line of thinking for anything and everything, except one thing — the good will.

The good will unlike anything else is good unconditionally and what makes a good will good is willing alone; not other attitudes, or consequences, or characteristics of the agent. Even Kant thinks this sounds like a rather strange idea. So how can he (and we) be confident that the good will even exists?

Consider Mahatma Gandhi’s (1869–1948) non-violent protest for Indian independence. He stood peacefully whilst the British police beat him. Here is a case where there must have been an overwhelming desire to fight back. But he did not. In this type of action Kant would claim that we “see” the good will — as he says — “shining like a jewel”.[3] Seeing such resilience in the face of such awful violence we are humbled and can recognize, what Kant calls, its moral worth. Obviously not all actions are as significant as Gandhi’s! However, Kant thinks that any acts like this, which are performed despite conflicting desires, are due to the good will. Considering such actions (can you think of any?) means we can recognize that the good will exists.

Acting for the Sake of Duty and Acting in Accordance with Duty

From what we have said above about the nature of duty and good will we can see why Kant says that to act from good will is acting for the sake of duty. We act despite our desires to do otherwise. For Kant this means that acting for the sake of duty is the only way that an action can have moral worth. We will see below what we have to do for our actions to be carried out for the sake of duty. However, before we do this, we need to be really clear on this point about moral worth.

Imagine that you are walking with a friend. You pass someone begging on the street. Your friend starts to weep, fumbles in his wallet and gives the beggar some money and tells you that he feels such an empathy with the poor man that he just has to help him.

For Kant, your friend’s action has no moral worth because what is moving him to give money is empathy rather than duty! He is acting in accordance with duty. However, Kant does think your friend should be applauded as such an action is something that is of value although it wouldn’t be correct to call it a moral action.

To make this point clearer, Kant asks us to consider someone who has no sympathy for the suffering of others and no inclination to help them. But despite this:

…he nevertheless tears himself from his deadly insensibility and performs the action without any inclination at all, but solely from duty then for the first time his action has genuine moral worth.[4]

In contrast to our friend, this person is acting for the sake of duty and hence their action is moral. We must be careful though. Kant is not telling us to become emotionally barren robots! He is not saying that before we can act morally we need to get rid of sympathy, empathy, desires, love, and inclinations. This would make Kant’s moral philosophy an absurd non-starter.

Let us see why Kant is not saying this. Consider an action such as giving to others. We should ask whether an action of giving to others would have been performed even if the agent lacked the desire to do so. If the answer is “yes” then the act has moral worth. This though is consistent with the agent actually having those desires. The question for Kant is not whether an agent has desires but what moved the agent to act. If they acted because of those desires they acted in accordance with duty and their action had no moral worth. If they acted for the sake of duty, and just happened to have those desires, then their action has moral worth.

Categorical and Hypothetical Imperatives

If we agree with Kant and want to act for the sake of duty what should we do? His answer is that we have to act out of respect for the moral law. He has two examples of how this works in practice: lying and suicide. We look at the former in Chapter 13, we will consider Kant’s example of suicide at the end of this chapter. However, before doing this we need to get a sense of what Kant has in mind when he talks about acting out of respect for the moral law.

The moral law is what he calls the “Categorical Imperative”. He thinks there are three formulations of this.

Formulation Shorthand Imperative
First Formulation C-1 …act only according to that maxim through which you can at the same time will that it become a universal law.[5]
Second Formulation C-2 So act that you use humanity, in your own person as well as in the person of any other, always at the same time as an end, never merely as a means.[6]
Third Formulation C-3 …every rational being must so act as if he were through his maxim always a lawmaking member in the universal kingdom of ends.[7]

We will consider these in turn, showing how they are linked. Consider then, CI-1. Kant’s idea is that we use this “test” to see what maxims are morally permissible. If we act in accordance with those then we are acting from duty and our actions have moral worth. Let us look at what this means.

Initially it is worth considering what “categorical” and “imperative” mean. An imperative is just a command. “Clean your room!” is an imperative I give my daughter every Saturday. “Do not park in front of these gates!” is a command on my neighbor’s gate. “Love your God with all your heart, mind and soul” is a command from the Bible.

What about the “categorical” part? If a command is categorical then people ought to follow it irrespective of how they feel about following it, irrespective of what consequences might follow, or who may or may not have told them to follow it. For example, the command “do not peel the skin of babies” is categorical. You ought not to do this and the fact that this might be your life’s ambition, or that you really want to do it, or that your teacher has told you to do it, is completely irrelevant.

Contrast this with Hypothetical Imperatives. If I tell my daughter to clean her room, this is hypothetical. This is because whether she ought to clean her room is dependent on conditions about her and me. If she does not care about a clean room and about what her dad thinks, then it is not true that she ought to clean her room. Most commands are hypothetical. For example, “study!” You ought to study only if certain things are true about you; for example, that you care about doing well, that you want to succeed in the test etc.

Kant thinks that moral “oughts” — for example, “you ought not lie” — are categorical. They apply to people irrespective of how they feel about them.

The next thing we need is the idea of a “maxim”. This is relatively simple and is best seen through the following examples. Imagine I’m considering whether to make a false promise. Perhaps I think that by falsely promising you that l will pay you back I will be more likely to get a loan from you. In that case my maxim is something like “whenever I can benefit from making a false promise I should do so”.

Imagine I decide to exercise because I feel depressed, then I may be said to be acting on the maxim “Whenever I feel depressed I will exercise”. A maxim is a general principle or rule upon which we act. We do not decide on a set of maxims, perhaps writing them down, and then try to live by them but rather a maxim is the principle or rule that can make sense of an action whether or not we have thought about it in these terms.

The First Formulation of the Categorical Imperative

Let’s put these bits together in relation to CI-1

…act only according to that maxim through which you can at the same time will that it become a universal law.[8]

The “test” that CI-1 prescribes is the following. Consider the maxim on which you are thinking about acting, and ask whether you can either

  1. conceive that it become a universal law, or
  2. will that it become a universal law.

If a maxim fails on either (i) or (ii) then there is no good reason for you to act on that maxim and it is morally impermissible to do so. If it passes the CI test, then it is morally permissible.

Kant is not saying that the CI-1 test is a way of working out what is and what is not moral. Presumably we can think of lots of maxims, which are non-moral, which pass the test, for example, “whenever I am bored I will watch TV”.

Equally he is not saying that if a maxim cannot be universalized then it is morally impermissible. Some maxims are just mathematically impossible. For example, “whenever I am going to exercise I will do it for an above the average amount of time”. This maxim cannot be universalized because we cannot conceive that everyone does something above “average”.

Finally, it is worth remembering that the maxim must be able to be willed as a universal law. This is important because maxims such as “if your name is Jill and you are 5ft 11, you can lie” will fail to be universalized because you cannot will that your name is Jill or that your height is 5ft11. It has to be possible to will as a universal law and for this to be true it must be at least possible for it actually to come about. This shows that the common concern that we can get any maxim to pass the CI-1 test by simply adding more and more specific details, such as names, heights or locations, fails. This is very abstract (what did we tell you about Kant’s work!). Let us consider an example.

Perfect and Imperfect Duties

Recall the example of making a false promise to secure a loan. The maxim is “whenever I can benefit from doing so, I should make a false promise”. The question is whether I could conceive or will that this become a universal law.

I could not. If everyone followed this maxim then we would all believe everyone else could make a false promise if it would benefit them to do so. Kant thinks such a situation is not conceivable because the very idea of making a promise relies on trust. But if “whenever it is of benefit to you, you can make false promises” was to become a universal law then there would be no trust and hence no promising. So, by simply thinking about the idea of promising and lying we see the maxim will fail the test and, because we cannot universalize the maxim, then making a false promise becomes morally impermissible. This is true universally for all people in all circumstances for anyone can, in principle, go through the same line of reasoning.

A maxim failing at (i) is what Kant calls a contradiction in conception, and succeeding at (i) means we are dealing with what Kant calls a perfect duty. In our example we have shown we have a perfect duty not to make false promises.

Consider another example. Imagine that someone in need asks us for money but we decide not to help them. In this case our maxim is “whenever someone is in need and asks for money do not give them money”. Does this pass the CI-1 test?

No it fails the CI-1 test. Although it is true that the maxim passes (i) not giving to the needy does not threaten the very idea of giving money away. Kant thinks that anyone thinking about this will see that that maxim will fail at (ii) and hence it is morally impermissible. Here is why.

You cannot know if you will be in need in the future and presumably you would want to be helped if you were in need. In which case you are being inconsistent if you willed that “people should not help those in need” should become a universal law. For you might want people to help those in need in the future, namely, you.

So we cannot will the maxim “whenever someone is in need do not help them” to become a universal moral law. Again this is a thought process that anyone can go through and it means that this moral claim is true universally for all people in all circumstances. Failing at (ii) is what Kant calls a contradiction in will, and failing at (ii) means we are dealing with what Kant calls an imperfect duty.

It is absolutely key to recognize that CI-1 is not simply asking “what if everyone did that?” CI-1 is not a form of Utilitarianism. (See Part I: Moral Theories Utilitarianism.) Kant is not saying that it is wrong to make false promises because if people did then the world would be a horrible place. Rather Kant is asking about whether we can conceive or will the maxim to become a universal law.

Second Formulation of the Categorical Imperative

The second formulation CI-2 is the following:

So act that you use humanity, in your own person as well as in the person of any other, always at the same time as an end, never merely as a means.

Timoclea Kills the Captain of Alexander the Great by Elisabetta Sirani (1659)
Timoclea Kills the Captain of Alexander the Great by Elisabetta Sirani (1659). Timoclea threw the captain down a well, actually. Kant would say that Timoclea is not treating the captain as an end-in-himself and only as a means to her own end.

Kant thinks that CI-1 and CI-2 are two sides of the same coin, though precisely how they are related is a matter of scholarly debate. Put very simply CI-2 says you should not use people, because if you do, you are failing to treat them as a rational agent and this is morally wrong.

For example, if I use your essay without your knowledge then I have not treated you as a rational agent. I would have done had I asked you for your essay and you had freely chosen to let me have it. But given that I did not ask you, I was in a sense making choices on your behalf and thus did not treat you as a rational agent. So according to Kant I should always treat you as an end not a means. I should always treat you as a free rational agent.

Kant’s theory then has a way of respecting the dignity of people. We should treat people with respect and with dignity purely on the basis that they are rational agents, and not because of their race, gender, education, upbringing etc. From this you can also see that Kant’s theory allows us to speak about “rights”. If someone has a right then they have this right irrespective of gender, education, upbringing etc. For example, Jill has a right to free speech because she is a person, consequently that right will not disappear if she changes her location, personal circumstances, relationship status, political viewpoint etc. After all she does not stop being a person.

Importantly, CI-2 does not say that you either treat someone as a means or an end. I could treat someone as an end by treating them as a means. Suppose that you have freely decided to become a taxi driver. If I use you as a means by asking you to take me to the airport I am also treating you as an end. But Kant does not believe this to be morally wrong because I am respecting you as a rational agent; after all, you chose to be a taxi driver. Of course, if I get into your car and point a gun at your head and ask to be taken to the airport then I am not treating you as an end but rather solely as a means, which is wrong.

The Third Formulation of the Categorical Imperative and Summary

The final formulation of the Categorical Imperative is a combination of CI-1 and CI-2. It asks us to imagine a kingdom which consists of only those people who act on CI-1. They never act on a maxim which cannot become a universal law. In such a kingdom people would treat people as ends, because CI-2 passes CI-1. This is why CI-3 is often called the “Kingdom of Ends” formulation:

…every rational being must so act as if he were through his maxim always a lawmaking member in the universal kingdom of ends.

In summary, we have seen that Kant thinks that acts have moral worth only if they are carried out for the sake of duty. Agents act for the sake of duty if they act out of respect for the moral law, which they do by following the Categorical Imperative in one of its formulations.

Consequently, Kant thinks that acts are wrong and right universally, irrespective of consequences and desires. If lying is wrong then it is wrong in all instances. From all this, it follows that we cannot be taught a set of moral rules for each and every situation and Kant believes that it is up to us to work it out for ourselves by thinking rationally.

There have been, and continue to be, many books and journal articles written about Kant’s ethics. He has a profound and deep insight into the nature of morality and he raises some fundamental questions about what it is to be human. Kant’s moral theory is radically Egalitarian as his theory is blind to individual personal circumstances, race, gender and ethnicity. Everyone is equal before the moral law!

Related to this, his theory respects the rights of individuals and, relatedly, their dignity. Any theory that is to have a hope of capturing our notion of rights needs to be able to respect the thought that a right is not something that disappears if circumstances change. Jill has a right to life, period; we do not say Jill has a right to life “if…” and then have to fill in the blanks. This is precisely something that Kant’s theory can give us. CI-1 generates maxims which do not have exceptions and CI-2 tells us that we should always treat everyone as an end in themselves and never solely as a means to an end. It tells us, for example, that we ought not to kill Jill, and this holds true in all circumstances.

There are, though, a number of tough questions that Kant’s work raises. We consider some of these below. However, as with all the philosophical ideas we discuss in this book, Kant’s work is still very much alive and has defenders across the world. Before we turn to these worries, we work through an example that Kant gives regarding suicide.

Kant on Suicide

Kant is notoriously stingy with examples. One he does mention is suicide. This is an emotive topic and linked to questions about mental health and religion. An attraction of Kant’s view is the ability to apply his Categorical Imperatives in a dispassionate way. His framework should allow us to “plug in” the issue and “get out” an answer. Let’s see how this might work.

Kant thinks that suicide is always wrong and has very harsh words for someone who attempts suicide:

He who so behaves, who has no respect for human nature and makes a thing of himself, becomes for everyone an Object of freewill. We are free to treat him as a beast, as a thing, and to use him for our sport as we do a horse or a dog, for he is no longer a human being; he has made a thing of himself, and, having himself discarded his humanity, he cannot expect that others should respect humanity in him.[9]

But why does he think this? How does this fit with Kant’s Categorical Imperatives? We will look at the first two formulations.

Fundamental to remember is that for Kant the motive that drives all suicide is “avoid evil”. By which he means avoiding suffering, pain, and other negative outcomes in one’s life. All suicide attempts are due to the fact that we love ourselves and thus want to “avoid evils” that may befall us.

Imagine then that I decide to commit suicide. Given what we have just said about my motives this means I will be acting on this maxim: “From self-love I make as my principle to shorten my life when its continued duration threatens more evil than it promises satisfaction”.13

Following CI-1 the question then is whether it is possible to universalize this maxim? Kant thinks not. For him it is unclear how we could will it that all rational agents as the result of self-love can destroy themselves when their continued existence threatens more evil than it promises satisfaction. For Kant self-love leading to the destruction of the self is a contradiction. Thus he thinks that we have a perfect (rather than an imperfect) duty to ourselves not to commit suicide. To do so is morally wrong. This is how Kant puts it:

One sees at once a contradiction in a system of nature whose law would destroy life [suicide] by means of the very same feeling that acts so as to stimulate the furtherance of life [self-love], and hence there could be no existence as a system of nature. Therefore, such a maxim cannot possibly hold as a universal law of nature and is, consequently, wholly opposed to the supreme principle of all duty.[10]

Notice a few odd things here in relation to CI-1. The point about universalization seems irrelevant. Kant could have just said it is a contradiction to will from self-love the destruction of oneself. It seems that there is nothing added by asking us to consider this point universalized. It does not add weight to the claim that it is a contradiction.

Second, it is not really a “contradiction” at all! It is different to the lying promise example. In this it seems that the very concept of a promise relies on trust, which lying would destroy. In contrast in the suicide case the “contradiction” seems more like a by-product of Kant’s assumption regarding the motivation of suicidal people. So we can avoid the “contradiction” if we allow for the possibility that suicide need not be driven by self-love. If this were true then there would be no “contradiction”. Hence, it seems wrong to call the duty not to kill oneself — if such a duty exists — a “perfect” duty. So the first formulation does not give Kant the conclusion that suicide is morally wrong.

Moving to the second formulation. This helps us understand Kant’s harsh assessment of people attempting suicide. Remember he calls such people “objects” or “beasts” or “things”. So, what is the difference between beasts or objects or things, and humans? The answer is that we are rational. Recall, that for Kant our rationality is of fundamental value. If anyone’s actions do not recognize someone else’s rationality then they have done something morally wrong. This amounts to treating them as merely means to our own end. Given all this you can see what Kant is getting at. For him committing suicide is treating yourself as a mere means to some end — namely the end of avoiding pain and suffering etc. — and not an end in itself. You are treating yourself as a “beast” a “thing” an “object”, not as a human being with the gift of reason. This is morally wrong.

Moreover, if you do this, then others treating you with respect as a rational person can conclude that you also want others to treat you in this way. Because if you are rational then you must think that it is OK to universalize the maxim that we can treat others as objects, beast and thing. They can thus treat you as a beast, object, and thing and still be treating you with respect as a rationale agent. With regard to attempting suicide your action is wrong because you have ignored your own rationality. You have treated yourself as a mere means to an end.

But, like the first formulation this is very weak. It is unclear why in attempting suicide you are treating yourself as a mere means to an end. You might think you are respecting your rationality by considering suicide. Recall, Kant says that it is sometimes fine to treat people as a means to an end, e.g. a taxi driver. It is fine where people have given consent for you to treat them that way. In that case, suicide might be like the taxi driver case. We have freely decided to treat ourselves as a means to an end. We are, then, treating ourselves as a rational agent and not doing something morally wrong by committing suicide. There are some other things that Kant says about the wrongness of suicide that do not link to the Categorical Imperatives. For example, he talks about humans being the property of God and hence our lives not being something we can choose to extinguish. However, we need not discuss this here.

There is a consensus between Kant scholars that, as it stands, Kant’s argument against suicide fails. There are some though who use Kant’s ideas as a starting point for a more convincing argument against suicide. For example, see J. David Velleman (1999) and Michael Cholbi (2000).

Problems and Responses

Conflicting Duties

If moral duties apply in all circumstances, then what happens when we have duties which conflict? Imagine that you have hidden some Jewish people in your basement in Nazi Germany. Imagine then that an SS officer knocks at your door and asks if you are hiding Jews? What might Kant’s theory tell us to do? Our duty is to refrain from lying so does this mean we are morally required to tell the SS officer our secret? If this is the conclusion then it makes Kant’s theory morally repugnant.

However, there is no requirement in Kant’s theory to tell the truth, there is just a requirement not to lie. Lying is about intentional deceit, so maybe in this example there is a way not to lie. For example, if we simply stayed silent.

Even if we respond in this sort of way in this example, presumably we can engineer an example that would not allow for this. For example, perhaps we are in a law court and the SS officer asks us under oath. In that example, silence would not be an option. This certainly would seem to count against Kant’s theory for it does seem morally wrong to reveal the location of the Jewish people.

The main point though is that Kant thinks we need to take the features of each individual situation into account. He does not just want us to mindlessly apply generic rules whilst paying no attention to what is before us. Peter Rickman writes regarding these types of cases:

…it should be plain that more than one imperative/moral principle is relevant to the situation. Certainly we should tell the truth; but do we not also have a duty to protect an innocent man from harm? Further, do we not have an obligation to fight evil? We are confronted with a conflict of values here. Unfortunately, as far as I know, there is no explicit discussion of this issue in Kant. One could assume, however, that his general approach of distinguishing the lesser from the greater evil should be applied. I think Kant might say that although lying is never right, it might be the lesser evil in some cases.[11]

The point is not that these sorts of examples are “knock down” criticisms of Kant’s theory but rather that Kant’s theory is underspecified and fails to give guidance with these specific sorts of cases. In fact, we might think that this is an advantage of his theory that has given us the supreme principle of morality and the general way of proceeding but has left it up to us to work out what to do in each situation. We will leave the reader to see if this can be done and in particular, whether it can be done in a way consistent with the other aspects of his moral theory.

Problems and Responses: The Role of Intuitions

One of the most common criticisms leveled at Kant’s theory is that it is simply counter intuitive. For example, lying, for him, is morally impermissible in all instances irrespective of the consequences. Yet we seem to be able to generate thought experiments that show that this is a morally repugnant position.

However, in Kant’s defense we might ask why we should use our intuitions as any form of test for a moral theory. Intuitions are notoriously fickle and unreliable. Even if you pick the oddest view you can think of, you would probably find some people at some point in time that would find this view “intuitive”. So how worried should we be if Kant’s theory leads to counter intuitive consequences? This then raises a more general methodological question to keep at the forefront of your mind when reading this book. What role, if any, should intuitions have in the formation and the testing of moral theory?

Problem and Responses: Categorical Imperatives and Etiquette

Kant argues that what we are morally required to do is a matter of reason. If people reason in the right way then they will recognize, for example, that lying is wrong. However, some philosophers, for example Philippa Foot (1920–2010), have worried about this link to reason. The strength of Foot’s challenge is that she agrees that morality is a system of Categorical Imperatives but says that this need not be due to reason.

Foot uses the example of etiquette to motivate her argument.[12] Rules of etiquette seem to be Categorical Imperatives but are not grounded in reason. Consider an example. I had a friend at university who was a sportsman. He was in many teams, his degree was in sports and exercise and if there were ever a spare minute he would be running, on his bike or in the pool. Unsurprisingly he wore a tracksuit and trainers all the time!

During our second year at university a mutual friend died. There was a big formal funeral arranged. My friend decided to go to this funeral in his tracksuit and trainers. I asked him about this and his response was that it was what he liked wearing. However, to my mind at least, this reason, which was based on his desire, did not change the fact that he really ought not have worn a tracksuit. Foot would agree and thinks that rules of etiquette are categorical because they are not dependent on any particular desires someone would have.

However, even if they are categorical, Foot thinks that rules of etiquette are not rules of reason. We do not think that if we reasoned correctly we would recognize that we ought not to wear tracksuits to funerals, or (to think of some other rules of etiquette) we ought not to reply to a letter written in the third person in the first person, or we ought not to put our feet on the dinner table during a meal etc. It is not simply a matter of thinking in the right way but rather to recognize these “oughts” as part of a shared cultural practice.

So although this does not show that Kant is wrong, it does throw down a challenge to him. That is, we need independent reasons to think that the categorical nature of moral “oughts” are based on reason and not just part of a shared cultural practice. To respond to this challenge, the Kantian would have to put forward the argument that in the particular case of moral “oughts”, we have a good argument to ground the categorical nature in reason rather than institutional practices.

Problems and Responses: The Domain of Morality

Kant thinks that the domain of morality is merely the domain of reasons and as far as we are agents who can reason then we have duties and rights and people ought to treat us with dignity. The flip side of this is that non-rational agents, such as non-human animals, do not have rights and we can, according to Kant, treat them as we like!

The challenge to Kant’s theory is that the scope of morality seems bigger than the scope of reasons. People do think that we have moral obligations toward non-rational agents. Consider someone kicking a cat. We might think that morally they ought not to do this. However, Kant’s theory does not back this up because, as far as we know, cats are not rational agents. Despite it not being wrong to treat animals in this way, Kant still thinks that we should not, because if we did, then we would be more likely to treat humans in this way.


Kant’s moral theory is extremely complicated and badly expressed. However, it is hugely influential and profound. As a system builder Kant’s work starts with rational reflection from which he attempts to develop a complete moral system.

He starts from the notion of duty. He shows that what allows us to act for the sake of duty is the good will, and that the good will is unconditionally good. If we want to act for the sake of duty we need to act out of respect for the moral law and this amounts to following the Categorical Imperative. Kant argues that in following the Categorical Imperative, agents will converge on what is morally permissible. Hence Kant can talk about absolute and objective moral truths.

Common Student Mistakes

  • Confusing acting in accordance with duty and acting for the sake of duty.
  • Thinking that Kant’s theory has no room for emotions.
  • Thinking that Kant’s Categorical Imperative can be summed up in the question: “how would you like it if everyone did that”?
  • Thinking that the Categorical Imperative is a form of Utilitarianism.
  • Thinking Kant believes you can never treat someone as a means to an end.


Topics of Discussion

  1. Think about your life. Do you think there are things you “ought to do”?
  2. Do you think that there are things you ought to do irrespective of your desires and inclinations?
  3. What are Categorical and Hypothetical Imperatives? Do you think that rules of etiquette are categorical or hypothetical?
  4. How might Kant respond to the SS officer example?
  5. Can you think of some examples where you might be treating someone solely as means-to-an-end?
  6. Would capital punishment pass the CI-2 test?
  7. How might CI-2 relate to prostitution? Do you think that Kant would say that it is morally permissible?
  8. Why might Kant’s theory be well placed to respect people’s rights?
  9. Do you think we have any moral obligations towards animals? What would Kant say?
  10. What role do you think intuitions should have in assessing moral theories?


Key Terminology

  • A priori
  • Categorical Imperative
  • Deontological
  • Duty
  • Egalitarian
  • Good will
  • Hypothetical Imperative
  • Maxim
  • Rationalist
  • Rights

Media Attributions

Timoclea Kills the Captain of Alexander the Great by Elisabetta Sirani 1659 © Elisabetta Sirani is licensed under a Public Domain license

Media Attributions

  1. Immanuel Kant, Groundwork for the Metaphysic of Morals, ed. Jonathan Bennett (Early Modern Texts, 2008), 39, https://web.archive.org/web/20171002211626/http://www.earlymoderntexts.com/assets/pdfs/kant1785.pdf.
  2. Kant, 40.
  3. Kant, 40.
  4. Kant, 43.
  5. Kant, 15.
  6. Kant, 66.
  7. Kant, 21.
  8. Kant, 21.
  9. Immanuel Kant, Lectures on Ethics (Methuen & Co., 1930), pt. 27, p. 373.
  10. Kant, Groundwork for the Metaphysic of Morals.
  11. Peter Rickman, “Having Trouble With Kant? | Issue 86 | Philosophy Now,” Magazine, Philosophy Now, July 2017, https://web.archive.org/web/20170724103219/https://philosophynow.org/issues/86/Having_Trouble_With_Kant.
  12. Philippa Foot, “Morality as a System of Hypothetical Imperatives,” Philosophical Review 81, no. 3 (1972): 305–16.


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Kantian Ethics Copyright © 2020 by Andrew Fisher and Mark Dimmock is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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