Do Your Duty: Kant

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Do Your Duty: Kant

Who is Kant?

Immanuel Kant (1724-1804) was a renowned German philosopher whose ideas have had a profound and lasting impact on the fields of ethics, metaphysics, and epistemology. Kant was born in the small Prussian city of Königsberg and spent most of his life working as a professor at the local university. In his moral philosophy, he emphasizes the importance of rational autonomy, the ability to act according to self-imposed moral principles rather than being driven solely by external forces or desires. Kant sees this ability as the source of both human dignity and moral duty.

This digital essay presents key selections from Kant’s Groundwork for the Metaphysics of Morals, a short book he wrote in 1785 to explain the key points of his moral philosophy (which is developed across other, longer works).

Kant’s Moral Philosophy: A Brief Overview

Kant’s philosophy is notoriously complex and difficult, but the basic ideas of his moral theory are fairly easy to grasp. For Kant, a moral agent has a good will insofar as they act consistently from duty. To act from duty is to follow the moral law, also known as the categorical imperative. The categorical imperative commands us to act only in ways that could rationally be made into universal laws.

This emphasis on acting from duty places Kant’s moral philosophy in sharp contrast with John Stuart Mill’s utilitarianism. For Mill, the moral status of an action depends entirely on its consequences (specifically, on how much overall utility it brings about), whereas for Kant, the outcomes of an action are morally irrelevant: all that matters is whether the action is based on principles that align with our moral duty.

Kant’s moral philosophy also differs significantly from Aristotle’s. In contrast with Aristotle’s central emphasis on achieving happiness (eudaimonia) through virtuous living, Kant prioritizes acting from moral duty, regardless of whether it leads to personal happiness.

Key Principle

A Good Will

Kant begins his essay with this famous passage on what we deserve moral credit and blame for:

  • Nothing can possibly be conceived in the world, or even out of it, which can be called good without qualification, except a good will. Intelligence, wit, judgment, and the other talents of the mind, or courage, resolution, perseverance, as qualities of temperament, are undoubtedly good and desirable in many respects; but these gifts of nature may also become extremely bad and mischievous if the will that makes use of them is not good. It is the same with the gifts of fortune: power, riches, honor, even health, and the general well-being and contentment with one’s condition which is called happiness, inspire pride, and often presumption, if there is not a good will to correct their influence on the mind. The sight of a being devoid of a pure and good will enjoying unbroken prosperity can never give pleasure to an impartial rational spectator. Thus a good will is the indispensable condition even of being worthy of happiness.

    There are even some qualities which are of service to this good will itself and may facilitate its action, yet which have no intrinsic unconditional value, but always presuppose a good will. This qualifies the esteem we justly have for them and does not permit us to regard them as absolutely good. Moderation, self-control, and calm deliberation are not only good in many respects, but even seem to constitute part of the intrinsic worth of the person; but they are far from deserving to be called good without qualification. For without the principles of a good will, they may become extremely bad, and the coolness of a villain not only makes him far more dangerous, but also directly makes him more abominable in our eyes than he would have been without it.

    A good will is good not because of what it does or brings about, but simply by virtue of the volition; that is, it is good in itself; and considered by itself it is to be esteemed much higher than all that it bring about in favor of any inclination, or even of the sum total of all inclinations.

    Even if, owing to special disfavor of fortune, this will should wholly lack power to accomplish its purpose, if with its greatest efforts it should yet achieve nothing—even then, like a jewel, it would still shine by its own light, as a thing which has its whole value in itself. Its usefulness or fruitlessness can neither add nor take away anything from this value.

Key Principle

The Basis of Moral Value

Kant also tells us that moral value depends on the capacity for autonomy. This is what distinguishes persons from mere things.

  • Beings whose existence depends, not on our will, but on nature, have nonetheless, if they are non-rational beings, only a relative value as means and are consequently called things.  Rational beings, on the other hand, are called persons because their nature already marks them out as ends in themselves—that is, as something which ought not to be used merely as a means—and consequently imposes a limit on all arbitrary treatment of them. Persons, therefore, are not merely subjective ends whose existence as an effect of our actions has a value for us: they are objective ends—that is, things whose existence is in itself an end, and indeed an end in place of which we can put no other end to which they should serve merely as a means.

When Kant says that a person should never be used “merely as a means”, he means that it is always wrong to use someone else as if they are just a tool for you to achieve your own goals, exploiting or manipulating them without regard for their preferences or moral worth. To do so is to disregard their rationality and autonomy, and therefore represents a failure to treat them with the respect and dignity all persons deserve.

Key Principle

Acting from Duty, with Examples

Acting from Duty, with Examples

We must develop the notion of a will that deserves to be highly esteemed for itself and is good without a view to anything further, and which in estimating the value of our actions always takes the first place and constitutes the condition of all the rest. To do this, we will inspect the concept of duty, which includes that of a good will, although implying certain subjective limitations and hindrances. These, however, far from concealing it, or making it unrecognizable, rather bring it out by contrast and make it shine forth all the more brightly.

I omit here all actions already recognized as contrary to duty, for with these the question whether they are done from duty cannot arise at all. I also set aside actions that conform to duty, but to which men have no direct inclination, performing them because they are impelled to do so by some other inclination. For in this case it is easy to distinguish whether the action is done from duty or from a self-serving purpose. It is much harder to notice this distinction when the action accords with duty and the subject also has a direct inclination towards it.

Kant first offers an example of an action that “accords with duty” but is motivated by self-interest. He argues that such an action does not express a “good will”.

It is always a matter of duty that a shopkeeper should not overcharge an inexperienced customer; and when there is much commerce the prudent merchant does not do this, but keeps a fixed price for everyone. But this is not enough to make us believe that the merchant has acted from duty and principles of honesty: his own advantage required it.

Next, as an example of an action that does express a “good will”, Kant presents a case in which someone does their duty even though they get no satisfaction from it:

  • To be beneficent when we can is a duty; and there are many minds so compassionate that, without any motive of vanity or self-interest, they find pleasure in spreading joy around them. But I maintain that in such a case an action of this kind, however proper and amiable it may be, has no true moral worth, but is on a level with other inclinations, e. g., the inclination to honor, which, if it is fortunately directed to that which is in fact in the general interest and in conformity with duty, and hence honorable, deserves praise and encouragement, but not high esteem. For the maxim lacks the moral import, namely, to do such actions not from inclination, but from duty. 
  •  Suppose that the mind of that philanthropist were clouded by his own sorrow, extinguishing all sympathy with others, and that, while he still has the means to benefit others in need, he is not touched by their trouble because he is absorbed with his own; and now suppose that he tears himself out of this insensibility, and does the action without any inclination to it, but simply from duty. Not until then does his action have its genuine moral worth. Further still: if nature has put little sympathy in some man’s heart; if he is by temperament cold and indifferent to the sufferings of others (perhaps because provided with the special gift of patience and fortitude toward his own, and supposes, or even expects, that others should have the same)—if nature had not formed him to be a philanthropist, would he not still find in himself a source from which to give himself a far higher worth than that of a good-natured temperament could be? Certainly! It is just there that the moral worth of the character is brought out, which is incomparably the highest of all: namely, that he is beneficent, not from inclination, but from duty.


Here is a key distinction we need to understand Kant’s discussion of these examples.

Some actions are done purely from inclination (desire). For example, if you meet a friend for ice cream because you enjoy spending time with your friend and are in the mood for ice cream, your action is done from inclination. Your motive has to do with personal feelings of friendship and enjoyment.

Some actions are done purely from duty. For example, if you return a wallet you find on the street to its rightful owner, even though you could have kept the money inside, simply because you believe it is the right thing to doand not because of a desire to be recognized as a good person, or a desire to feel good about yourself, etc.your action is done from duty. Your motive has to do with your recognition of your moral obligation, not with your personal desires.

Many actions are done from a mixture of inclination and duty.  For example, you might volunteer with a children’s charity both because you believe you have an obligation to help those in need (duty) and because the children are cute and make you laugh (inclination). In cases like this, Kant thinks you deserve moral credit only to the extent that your action was done from duty. For example, if your primary reason for volunteering is that it is your duty, then you are acting very admirably; but if you are mainly driven by the enjoyment you get, and moral obligation plays only a minor role in your motivation, then you are still acting somewhat admirably, but much less so.

Key Principle

The Categorical Imperative

Kant then goes on to give us a test to decide whether our reasons for acting are from duty.  

  • But what sort of law can that be, the conception of which must determine the will, even without paying any regard to the effect expected from it, in order that this will may be called good absolutely and without qualification? As I have deprived the will of every impulse which could arise to it from obedience to any law, there remains nothing but the universal conformity of its actions to law in general, which alone is to serve the will as a principle, that is:
  • Never act otherwise than so that you could also will that your maxim should become a universal law.
  • Now if all imperatives of duty can be deducted from this one imperative as from their principle, then, although it should remain undecided what is called duty is not merely a vain notion, yet at least we shall be able to show what we understand by it and what this notion means. Since the universality of the law according to which effects are produced constitutes what is properly called nature in the most general sense (as to form), that is the existence of things so far as it is determined by general laws, the imperative of duty may be expressed thus: 
  • Act as if the maxim of thy action were to become by thy will a universal law of nature. 

Breaking Down the Categorical Imperative

Breaking Down the Categorical Imperative

An imperative is a command. A maxim combines such a command with some reason for acting, and the result is a description of an action that we can recognize as intentional.

For instance: “Always wear sunscreen at the beach in order to avoid sunburn”; or: “Never cheat in order to get ahead”.

For Kant, every intentional action has a corresponding maxim, a description that combines a command to act with the reason for which you are acting.

The key to obeying the categorical imperative, then, is to make sure that you could consistently will that your maxim become a universal law. What does this mean?

A maxim would be a universal law if any agent who found herself in circumstances relevantly similar to the circumstances in which you now find yourself obeyed the maxim that you are now acting on.

The crucial question is, could this hypothetical world in which your maxim is a universal law exist without creating a contradiction or a conflict with another universal law of nature.

Kant thinks one categorical imperative is to not manipulate other rational agents by making lying promises to them:

  • The common reason of men in its practical judgments perfectly coincides with this and always has in view the principle here suggested. Let the question be, for example: May I when in distress make a promise with the intention not to keep it?

  • The shortest way, and an unerring one, to discover whether a lying promise is consistent with duty, is to ask myself, “Should I be content that my maxim (to extricate myself from difficulty by a false promise) should hold good as a universal law, for myself as well as for others? and should I be able to say to myself, ‘Every one may make a deceitful promise when he finds himself in a difficulty from which he cannot otherwise extricate himself?’ Then I presently become aware that while I can will the lie, I can by no means will that lying should be a universal law. For with such a law there would be no promises at all, since it would be in vain to allege my intention in regard to my future actions to those who would not believe this allegation, or if they over hastily did so would pay me back in my own coin. Hence my maxim, as soon as it should be made a universal law, would necessarily destroy itself. I do not, therefore, need any far-reaching penetration to discern what I have to do in order that my will may be morally good. Inexperienced in the course of the world, incapable of being prepared for all its contingencies, I only ask myself: Can you also will that your maxim should be a universal law? If not, then it must be rejected, not because of a disadvantage accruing from it to myself or even to others, but because it cannot enter as a principle into a possible universal legislation, and reason extorts from me immediate respect for such legislation.


Thought Experiment

More Examples of Acts that Violate the Categorical Imperative

More Examples of Acts that Violate the Categorical Imperative

A man reduced to despair by a series of misfortunes feels wearied of life, but is still so far in possession of his reason that he can ask himself whether it would not be contrary to his duty to himself to take his own life. He asks whether the maxim of his action could become a universal law of nature. His maxim is: “From self-love I adopt it as a principle to shorten my life when its longer duration is likely to bring more evil than satisfaction.” It is asked then simply whether this principle founded on self-love can become a universal law of nature.

Now we see at once that a system of nature of which it should be a law to destroy life by means of the very feeling whose special nature it is to impel to the improvement of life would contradict itself and, therefore, could not exist as a system of nature; hence that maxim cannot possibly exist as a universal law of nature and, consequently, would be wholly inconsistent with the supreme principle of all duty.

Another finds himself forced by necessity to borrow money. He knows that he will not be able to repay it, but sees that nothing will be lent to him unless he promises to repay it in a definite time. He desires to make this promise, but he has still so much conscience as to ask himself: “Is it not unlawful and inconsistent with duty to get out of a difficulty in this way?” Suppose however that he resolves to do so: then the maxim of his action would be expressed thus: “When I think myself in want of money, I will borrow money and promise to repay it, although I know that I never can do so.”

Now this principle of self-love or of one’s own advantage may perhaps be consistent with my whole future welfare; but the question now is, “Is it right?” I change then the suggestion of self-love into a universal law, and state the question thus: “How would it be if my maxim were a universal law?” Then I see at once that it could never hold as a universal law of nature, but would necessarily contradict itself. For supposing it to be a universal law that everyone when he thinks himself in a difficulty should be able to promise whatever he pleases, with the purpose of not keeping his promise, the promise itself would become impossible, as well as the end that one might have in view in it, since no one would consider that anything was promised to him, but would ridicule all such statements as vain pretenses.

A third, who is in prosperity, while he sees that others have to contend with great wretchedness and that he could help them, thinks: “What concern is it of mine? Let everyone be as happy as he can make himself; I will take nothing from him nor even envy him, only I do not wish to contribute anything to his welfare or to his assistance in distress!” Now no doubt if such a mode of thinking were a universal law, the human race might very well subsist and doubtless even better than in a state in which everyone talks of sympathy and good-will, or even takes care occasionally to put it into practice, but, on the other side, also cheats when he can, betrays the rights of men, or otherwise violates them.

But although it is possible that a universal law of nature might exist in accordance with that maxim, it is impossible to will that such a principle should have the universal validity of a law of nature. For a will which resolved this would contradict itself, inasmuch as many cases might occur in which one would have need of the love and sympathy of others, and in which, by such a law of nature, sprung from his own will, he would deprive himself of all hope of the aid he desires.

A fourth finds in himself a talent which with the help of some culture might make him a useful man in many respects. But he finds himself in comfortable circumstances and prefers to indulge in pleasure rather than to take pains in enlarging and improving his natural capacities. He asks, however, whether his maxim of neglect of his natural gifts, besides agreeing with his inclination to indulgence, agrees also with duty.

He sees then that a system of nature could indeed subsist with such a universal law although men should let their talents rest and resolve to devote their lives merely to idleness, amusement, and propagation of their species—in a word, to enjoyment; but he cannot possibly will that this should be a universal law of nature, or be implanted in us as such by a natural instinct. For, as a rational being, he necessarily wills that his faculties be developed, since they serve him and have been given him, for all sorts of possible purposes.


We must be able to will that a maxim of our action should be a universal law. This is the canon of the moral appreciation of the action generally. Some actions are of such a character that their maxim cannot without contradiction be even conceived as a universal law of nature, far from it being possible that we should will that it should be so. In others this intrinsic impossibility is not found, but still it is impossible to will that their maxim should be raised to the universality of a law of nature, since such a will would contradict itself. Thus it has been completely shown how all duties depend as regards the nature of the obligation (not the object of the action) on the same principle.


This digital essay was prepared by Paul Blaschko, Justin Christy, Meghan Sullivan, and GGL Fellow Sam Kennedy.