Kant’s catigorical imperative

Kant’s categorical imperative is a moral duty which is binding in all circumstances, in adherence to the principle of universality, that one should perform acts only with the will that they become universal. In this wise it differs substantially from Aristotle’s conception of virtue ethics, an ethical system that holds fulfillment and happiness, eudaimonia, to be the highest end of the human creature. While both Kant and Aristotle emphasize the importance of reason, with Aristotle the importance of the various virtues is recursive with respect to their proper end, human fulfillment, whilst with Kant adhering to the categorical imperative constitutes an end in and of itself.

Foundationally, Kant’s categorical imperative is a duty-based, or deontological, ethical precept (Carroll & Buchholtz, 2009, p. 295). Thus, Kant’s system of ethics is deontological, that is, it is based on duty (p. 295). As Carroll and Buchholtz explain, Kant’s categorical imperative is best known as follows: “’Act only according to that maxim by which you can at the same time will that it should become a universal law’” (p. 295). For Kant, the only true, intrinsic goods were based on an intrinsically good will: thus, the good action is done with the desire of the one who does it that this action become universal, i.e. that everyone else adhere to this principle (Carroll & Buchholtz, 2009, p. 295; Pollock, 2012, p. 26).

However, it is possible that one might genuinely desire an arguably immoral principle to become universal; thus, sincere good will and a desire for universality are not enough. This is why the categorical imperative also includes the maxim that one should treat humanity “’in every case as an end and never merely a means’” (Carroll & Buchholtz, 2009, p. 295). Thus, it is immoral to treat other people in a manner inconsistent with their inherent dignity and moral worth, i.e. by exploiting them, or manipulating them, etc. (p. 295). This formulation is in turn reified and expanded upon with Kant’s third formulation of the categorical imperative, the principle of autonomy, which holds that people are capable of discovering morality for themselves, and do not have to have it dictated to them by “God, the state, our culture, or anyone else” (p. 295). The key idea here is that morality can be discovered through reason: Kant’s view of human dignity and capability is such that he argues that every rational woman or man is capable of ascertaining morality on the basis of their faculties of reason, rather than having to merely rely on the dictates of religion, society, or the government (p. 295).

The starting point for Aristotle’s system of ethics is happiness: specifically, eudaimonia, ‘the good life’ (Paola, Walker, & Nixon, 2012, p. 13; Summers, 2009, p. 9). Actually, the word is difficult to translate: in Greek it means something akin to ‘flourishing’; in the context in which Aristotle uses it, it pertains to ‘the good life’ (Summers, 2009, pp. 9-10). Eudaimonia, in Aristotle’s virtue ethics, is something in which one engages, an activity or process of self-improvement through the cultivation of virtue and learning from one’s experiences (pp. 9-10). As such, Aristotle was concerned with how an individual could build character, in order to better enjoy their life, the idea being that a life so lived would be happier and more fulfilled (Paola et al., 2012, p. 13; Summers, 2009, p. 10).

A key point here is that in Aristotle’s thought, the two are complementary: they reinforce and encourage each other, rather than competing with one another (Paola et al., 2012, p. 13). A good example of this is Aristotle’s outlook on human behavior, specifically the continuum from indulgence to self-denial: rather than over-indulging in the pleasures of life or abstaining from them, the individual should seek the golden mean, enjoying life’s pleasures without allowing them to master one (Lundy & Janes, 2009, p. 251). By so doing, the virtuous individual cultivates virtue and, at the same time, maximizes their happiness—in other words, they engage in eudaimonia.

While both Kant and Aristotle framed concepts of right in terms of virtue, in many, many respects their moral philosophies are worlds apart. This can be seen by considering what the foundation of Kant’s concept of the categorical imperative is, that is to say, whether or not it is moored to a certain conception of value (Sensen, 2011). Sensen explained that in Kant’s system of ethics, happiness and pleasure are not the basis of the categorical imperative, at least in part because these will vary from person to person (pp. 265-266). However, even if some desire or some happiness was universally shared, the promotion and/or the attainment of this state would still not constitute “the basis of the moral law, since ‘this unanimity itself would still be only contingent’” (p. 266). A moral law is necessary, not contingent, in Kantian ethics: it is based on duty, not on whether or not it makes people happy (p. 267).

It is the categorical imperative that determines conceptions of good and value in Kantian ethics, not conceptions or experiences of goods, pleasures, and values that determine the categorical imperative (Sensen, 2011, pp. 269-270). The tail does not wag the dog: the categorical imperative is perceived through reason, and should be adhered to because it determines the good (p. 271). As Wood (2008) explained, in Kantian ethics a given moral imperative attains the status of a categorical imperative or moral duty not on the basis of whether or not it helps individuals to obtain their desires and be happy, but rather on the basis of whether or not it can reasonably “command us how to act irrespective of our wants or our contingent ends” (p. 67).

For example, Kant famously declared that lying violated the categorical imperative, even in a case wherein one was asked to conceal a fugitive from an attacker (Pollock, 2012, p. 27). Lying fails the universality test: no rational person could want lying to replace truth-telling in all circumstances, and lying entails the deceiving of others to manipulate them and exploit their lack of knowledge about a certain thing (i.e. whether or not one is concealing a fugitive), thus, one should never lie (p. 27). Thus the ‘categorical’ in ‘categorical imperative’: if lying is wrong, it is wrong in all circumstances, even if it might serve individual interests that seem good, i.e. fugitives’ desires to stay hidden. Not surprisingly, this particular example of Kant’s has drawn a great deal of criticism, since most moral philosophers, not to mention most people, tend to think that lying to protect a fugitive from an attacker that means them harm is perfectly justifiable, and may even be a moral imperative in its own right (p. 27).

Aristotle’s virtue ethics proffer a signal contrast with Kantian deontological ethics in that they are explicitly concerned with the value of virtue, that is, eudaimonia. Aristotle’s concern with eudaimonia stands directly opposed to Kant’s conceptions of pure moral duties that may, and often do, conflict with human desires. Again, the ultimate goal of cultivating virtue is to attain, engage with, and perfect eudaimonia: “a life of nobility and goodness”, in the apt summation of Summers (2009, p. 12). Aristotle observed that attaining a life free from fear, emotional reactivity, and thoughtless pleasure-seeking was difficult for many people, thus the challenge of cultivating a good and virtuous character (p. 12).

Although engaging in and attaining eudaimonia is a challenge, it is also a tremendous source of rewards for the individual who is capable of mastering themselves enough to do so (Paola et al., 2012, p. 13). By mastering themselves, the individual is able to overcome their subjection to fears, emotions, and pleasures, and by so doing they are able to obtain true happiness in the state of eudaimonia, which Aristotle understood “as the proper fulfillment of human beings” (p. 13). A key point to reiterate here is that Aristotle did understand that human desires are not always rational, and are not always guaranteed to ensure happiness and fulfillment (p. 13). This distinction is an important one, because it is only by cultivating virtue, by strengthening the character, by choosing the golden mean, that the individual is able to resist desires that are irrational and possibly harmful, at least if over-indulged in (p. 13). Consequently, the individual perfects the attainment of happiness and pleasure by cultivating virtue: virtue has a kind of recursive property in this wise, because it is defined in terms of its ability to maximize happiness and fulfillment (p. 13).

However, there is a certain convergence with Kantian ethics in Aristotle’s thought, because Aristotle too valued reason as a prerequisite to knowing virtue and cultivating it (Paola et al., 2012, p. 13). This is what distinguishes human beings from other creatures: they share many of our needs and at least some of our pleasures, but Aristotle believed that they could not share our potential for rationality and the happiness that it can beget if properly applied to one’s life (p. 13). Somewhat similarly, as seen, Kant believed in the use of reason to ascertain the categorical imperative, which determines the morally right and the good. However, again there is a seminal distinction, in that the goal of following Aristotle’s system of ethics is that state of happiness and fulfillment, whereas following Kantian ethics essentially constitutes an end in and of itself.

In Aristotle’s virtue ethics there are two basic classes of virtues: moral virtues on the one hand, and intellectual virtues on the other (Paola et al., 2012, p. 13). Moral virtues are “habitual dispositions to feel and act rightly with respect to characteristically human concerns”: in other words, to have a moral virtue is to possess the will and the predilection to act rightly with respect to some situation or concern (p. 13). If one feels fear, then the moral virtue of courage is needed. When one feels the customary bodily pleasures and pains inherent to the human condition, the moral virtue of temperance or moderation is needed to help one avoid either overindulgence on the one hand and self-denial on the other (p. 13).

The intellectual virtues are the means of gaining a more perfect understanding of one’s self, other people, and the cosmos: by following them, by cultivating them, the individual gains not only much new knowledge in a far more reliable fashion, but also wisdom (Paola et al., 2012, p. 14). This wisdom and insight in turn helps the individual to better reflect on their own life, which helps them to live in a happier and more fulfilled manner (p. 14). By cultivating these virtues, the individual finds a golden mean between the irrational, emotion-driven part of the soul responsible for appetites, and the rational, prudent part of the soul responsible for reason and higher morals (p. 13). This golden mean will vary for different people, inasmuch as different people have differing needs, differing desires, differing temptations, and so on (p. 14).

From all of this it would seem that both the starting points and the ends of Kantian deontological ethics and Aristotelian virtue ethics are very dissimilar: where Kant is concerned with reason-derived principles as the basis of good, irrespective of and often in opposition to human desires and happiness, Aristotle is concerned with the perfecting of happiness, and with the fulfillment of life thereby.  True, Aristotle recognizes the distinction between desires, often fickle and fleeting, and true fulfillment, and holds that reason is the means by which one should discern the virtues and cultivate them. This is an important area of convergence between Aristotelian and Kantian thought. But this serves to highlight the importance of certain questions: with respect to Kantian thought, why not consider human needs and well-being an essential goal? True, by themselves they should not serve as an absolute bellwether or lodestone of morality, but why not give them due consideration? And with respect to Aristotelian thought, how best to resolve the inevitable differences of opinion regarding the cultivation of the virtues and the fulfillment of life in eudaimonia? What happens when one individual’s vision of eudaimonia conflicts with another’s?


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Pollock, J. M. (2012). Ethical dilemmas and decisions in criminal justice (7th ed.). Belmont, CA: Wadsworth.

Sensen, O. (2011). Kant’s conception of inner value. European Journal of Philosophy, 19(2), pp. 262-280. Retrieved from

Summers, J. (2009). Theory of health care ethics. In E. E. Morrison (Ed.), Health care ethics: Critical issues for the 21st century (2nd ed.) (pp. 3-40). Sudbury, MA: Jones and Bartlett Publishers.

Wood, A. W. (2008). Kantian ethics. New York: Cambridge University Press.