The starting point for Kant’s ethics is the concept of a good will. According to him, there is nothing unconditionally good in the world except the good will of the person (Kant 2002 p. 9). He goes on to explain that “the good will is good not through what it effects or accomplishes, not through its efficacy for attaining any intended end, but only through its willing …” (Kant 2002 p. 10). The good will is the capacity of the person to recognise and to act from a duty to follow the moral law.

In parallel to the supremacy of the good will is the experience of duty, which is a central experience in the moral life for deontology. What is important for Kant is that actions should be done not only in accordance with the moral law (i.e. actions should be right) but actions should be done from a duty to the moral law (i.e. actions should be done out of a good will) and therefore have moral worth. Kant (2002 p. 13) gives the example of a merchant not overcharging his customers. His action may be right and in conformity with his duty as a merchant as he does what is expected of him. But his action is not necessarily done from a duty to the moral law, i.e. done from the intention of wanting to act honestly. It is only in the latter case that his action can be said to have moral worth.

Kant (2002 p. 14) also gives the example of a person who has no inclination to benefit those in distress. However, out of duty to the moral law he performs an action to benefit those in distress. In this situation his action has moral worth compared to someone who may find it easy to help those who are in need. This may appear strange at first but when we think about it, if we care for someone we love, why should that action have moral worth? Surely if we showed care to someone who we do not love, that action has moral worth? The same can be said for nurses who, out of duty to the moral law, show care for people who they do not know, especially for those who are very unappreciative, difficult or even aggressive; it can be said that in such situations the actions of nurses have moral worth.

For Kant, actions that are done from duty to the moral law demonstrate the autonomy of the person. Autonomy is a key concept in Kant’s system of ethics. An autonomous action is a moral action, i.e. it is an action performed because of the duty to the moral law. In nursing ethics and practice, the importance of acknowledging and respecting a person’s autonomy is considered to be very important (e.g. Sasso, et al. 2008 p. 835; NMBI 2014 p. 13). Yet, there has been much discussion in the literature regarding the meaning of autonomy as a concept and as an ethical principle together with its implication for nursing practice.⁴ Kant’s understanding of autonomy is not based on what a person might desire but is based on reason. Autonomy is framed as self-determination by reason and morality. An autonomous action is a free action because it is directed by reason rather than by desire. For Kant, real freedom is when we act not according to our desires but according to our reason and, by extension, duty to the moral law. Freedom is shown when we act according to our duty to the moral law.

But how do we determine our duties to the moral law? We do this through the supreme principle of morality, to which we now turn.

Kant puts forward the categorical imperative as the supreme principle of morality (Kant 2002 p. 8). The categorical imperative is a command that is binding irrespective of how we may feel about it, whether we are inclined to follow it or not, or whether there is a direct or indirect benefit to us personally. In other words, there are no conditions attached to it, no exceptions to be made, “no ifs or buts” (Bowie 2002 p. 4).

There is one categorical imperative but various formulations of it with different emphases. The three most commonly considered are:

The first formulation of the categorical imperative – “Act only in accordance with that maxim through which you can at the same time will that it become a universal law” (Kant 2002 p. 37) – is both a consistency test and a universal test of the principles underlying our proposed intentional actions (or what Kant describes as ‘maxims’). A maxim is a principle of intentional action (Kant 2002 p. 16). For Kant, all deliberate actions are carried out in accordance with a ‘maxim’ (Birondo 2007 p. 265). As explained by Herbert (1999 p. 248), “a maxim is a rule of behavior that can become evident to others through the examples that one’s actions set for them.” The categorical imperative asks us to consider whether the maxim underlying our actions is coherent when applied to everyone and whether it can be willed to become a universal moral law.

Maxims can throw up contradictions: Firstly, there are maxims that, by definition, are contradictory when they are universally applied, and secondly, there are maxims that cannot be willed to become universal laws for everyone (Kant 2002 p. 41).⁶ Kant uses the example of keeping a promise (Kant 2002 p. 39). Suppose I make a promise to pay back a loan but have no intention of doing so. Can this maxim (principle) – I promise to repay a loan with no intention of repaying it – be thought without contradiction if universally applied? Can I conceive of a world where such a maxim (principle) is followed by everyone? If everyone did this then the institution of promising would no longer make sense. We could conceive of a world where no one believes in promises any more so it would be pointless making a promise in the first place. Promise-making only makes sense if we believe that the person making the promise intends to make good on his/her promises. Of course, it is not completely implausible that people make promises that they do not intend to keep. Kant is, however, asking us to think of a world in which promise-making is based on a maxim of promise-breaking, which is self-defeating. To say that people break promises all the time, is not the point of the test. The test of the maxim is conceptual rather than consequential. In other words, we are not asking what would be the consequences of the action of not keeping a promise, but rather we are asking whether we can envisage a world where promise-keeping is based on a maxim (principle) of promise-breaking. Conceptually, this would not make any sense and would be a contradiction in thinking.

Another example given by Kant is willing a world in which people do not help others in need (Kant 2002 p. 40). There is no contradiction in thinking with this maxim when applied universally. In other words, it is possible to think of or conjure up a world in which no one helps those in need and therefore the maxim is not self-defeating (unlike with promise-breaking). However, there is a contradiction in our willing such a world. If we willed a world where no one would help others in need, we may actually need help at some stage and therefore we would have willed that we receive no help at that time. This would be a contradiction to our willing this maxim.

The first version of the categorical imperative provides a test for the maxims of our actions. In this way, as Timmons (2013 p. 220) explains, it is a decision-making procedure for our moral deliberation. But what is it that actually renders an action to be either morally right or wrong (Timmons 2013 p. 219)? Following Timmons (2013 p. 219), to answer this question we need to turn to the second version of the categorical imperative known as the practical imperative: “Act so that you use humanity, as much in your own person as in the person of every other, always at the same time as end and never merely as means” (Kant 2002 pp. 46–47).