In modern societies taxation is present everywhere in daily life and is a heatedly debated political issue. Everyone has to pay taxes and it would seem that many people are not very happy about the actual tax systems, whether it be that they think that they pay too much taxes or that the tax burden is unjustly distributed or that the tax revenue is wasted by the state. It is therefore no surprise that political philosophy and ethics has produced some literature about the justification and distribution of individual taxation as well as such issues as the ethics of global taxation, corporate taxation and methods used to avoid taxes. My own attempt in this chapter is situated within the capability approach—understood as a partial theory of justice— and is mainly concerned with the triangle of social justice, taxation and poverty. I attempt to justify taxation in general within the framework of the state’s duty of justice to alleviate poverty. Obviously, such an argument about why taxation is justified is intertwined with and based on an argument about how the state should use the tax revenue and some ideas about how the tax system should be designed. Taxation is to be used for the common good and to set-up and sustain justice and the tax system and the distribution itself of tax burdens and benefits should be just. Unfortunately, I will not have space in this chapter to say anything about why there is poverty in today’s world and I will also not say anything about how the current tax systems and the production of poverty are intertwined, for example by tax competition between states or tax avoidance by international corporations or rich individuals (Dietsch and Rixen 2014). Both pose several questions of justice that need to be addressed and I can only argue on a much more abstract level.

If taxation is connected in this way to justice it means that I view taxes not primarily as the price taxpayers pay for the public goods they consume. Such a benefit principle would restrict taxation to a kind of a mutual beneficial contract between a taxpayer and the state, which implies that taxpayers even have the right to resist paying taxes if they do not receive equivalent goods for it or if they do not need those goods (Feld and Frey 2007). The first problem of such an approach to justify taxation is that it is almost impossible to calculate the prices for several public goods such as security, parks and a clean environment, education or health care. The second problem is that it appears to give justification for a voluntary social exclusion of the rich and to an involuntary social exclusion of those who are not able to pay taxes, which would leave them without access to public goods. Both would negatively affect those who are poor, because they heavily rely on public goods and have less material resources to contribute to the state’s revenue and to pay privately for social services. The same is true for more vulnerable groups such as the elderly, people with special needs or people who are chronically ill.

In the first section I will present a very brief and imprecise sketch of a capability theory of justice to ground my later elaborations. In the second section I will then argue that poverty is a violation of justice because it deprives the poor of their central capabilities deprived and because those who are affected by it have justified claims towards the state to help them overcome their situation. In the third section I will then argue in favour of progressive taxation which exempts those who are less well-off and burdens more those who are better-off. The reduction of inequalities in income and wealth that is produced by progressive taxation and special taxes on wealth and capital income is a favourable side effect.

Every theory of social justice has to clarify at least five things: the metric of justice (what type of goods should be distributed), the rule or rules of justice (how they should be distributed), the context of justice (in which social context this distribution takes place), the agents of justice (who has certain claims or duties of justice), and the institutions of justice (who is responsible for justice actually happening). Obviously all are highly contested in the sense that there are many possible alternative theories which can be used to clarify them. My modest aim here is to present a sketch of answers to the first two questions from the perspective of the capability approach. I will do this with the aim of establishing the ground for my main objective which is to argue that poverty is a violation of social justice and that the state has the responsibility and duty to intervene. My guideline is that the goal of justice is to put all members of society, and eventually all humans, in a position to live their lives as autonomous and respected persons as far as it is possible for a society to do so. This orientation on autonomy and respect is driven by the importance to the individual of both aspects and by her ability to live a good life in the sense of a life that she views worth living. Autonomy in the sense I want to point out is closely tied to self-realization, which is not a mere individualistic project of modernity but has certain intersubjective and social preconditions that make it possible (Honneth 2014). The goal of justice is not an atomised society but one in which the individual and the social are in balance and respect is the hinge which links them. Without being respected by others individuals might be free but isolated and abandoned.

The first and most prominent contribution of the capability approach to discussions about justice is surely the presentation of an alternative metric of justice, namely capabilities and functionings (Robeyns 2005; Nussbaum 2011). Capabilities describe the real freedom to achieve functionings, and functionings are all possible beings and doings of a person, for example being healthy, being well nourished or being able to move from one place to another. This allows a focus on what people are really able to do and be in their lives and also allows evaluation of their objective well-being in this regard. But there are also certain difficulties that come with such a focus on capabilities and functionings. On the one hand capabilities and functionings are not easy to distribute and some people are just not able to reach some of them but for reasons that are not relevant for social justice. For example, the capability to be healthy can be made impossible by many reasons that are not controllable such as genetic variation, accidents or natural disasters. It is therefore not unjust, in all cases, that some people suffer from ill-health or are less healthy than others and it is not always possible to distinguish those cases which are neutral to justice from those which involve real injustices. In comparison a strict egalitarian resourcist approach would be satisfied if all persons receive the same amount of resources or basic goods. On the other hand the relation of capabilities and functionings is not uncomplicated itself and it is not always clear whether capabilities or functionings or both are the best metric of justice. Most capability theorists argue that capabilities are to be preferred because of the high value of autonomy and the ability to choose they entail (Nussbaum 2011). If one wants to fast, and for that reason not realize the functioning to be well nourished, then this is not a case of injustice but rather the expression of this person’s freedom. On the contrary a society would be unjust if it prohibited such autonomous decisions and forced its members to be well nourished even if some of them wished to fast. The major problem with capabilities as the metric of justice is that they are very difficult to measure and that it assumes a highly demanding concept of autonomy and freedom that a considerable number of people fall short of in real life. The functionings that a person is actually well nourished or healthy can be measured objectively but the respective capabilities cannot and it is highly speculative to try to decide whether persons do actually have a capability and choose not to realize the according functioning or if there are hidden or subtle constraints, such as cultural pressure, that limit their freedom to realize it. Also for those members of society who have only limited functionings to act autonomously, for example children or people with mental disabilities or severe dementia, the metric of capabilities is not adequate. For this reason, a fully comprehensive theory of justice will have to use capabilities and functionings to evaluate well-being and to guide the distributional pattern depending on the particular context to which it is applied.

Despite these difficulties an orientation on capabilities and functionings appears to be the right choice for the metric of justice for several reasons of which I would like to highlight two (Anderson 2010). On the one hand, they are sensitive to what people can actually achieve with the goods and resources they command. For example, a person with chronic illness can have a very different level of capabilities and functionings from a healthy person even though they both command the same amount of resources such as income. The chronically ill person may have to spend all her money to adapt her house or to get help to move from one place to another, while the healthy person does not have to spend extra money on her accommodation or mobility. Such differences are relevant for justice and can only be detected if one looks at what people can actually do and be. On the other hand, the capability approach circumvents the problem that subjective welfare can be misleading in that people adapt their preferences and their experiences to their own circumstances. For diverse reasons such as cultural habits or ideological pressure or lack of knowledge and education people are capable of feeling well and free and happy even under the worst and harshest living conditions. Under such conditions it is misleading to take the subjective view as sufficient and it is instead necessary to objectively evaluate how people are actually living (Sen 1983). If people suffer from ill-health where it is not necessary and if they are oppressed, then there is injustice no matter how well these people adapt to their situation and how high their subjective well-being might be. The capability approach is concerned with how people actually live and not so much with how many resources they command or how well they feel. Capabilities and functionings are ends and not means of justice.

Most capability theorists employ a sufficientarian rule of justice and argue that at least as a minimal condition of justice all humans are entitled to reach a certain threshold of central capabilities (Nussbaum 2011). On the one hand, sufficiency claims that it does not ultimately matter how people fare in comparison to each other so long as they are able to live a good life. A society in which all are sick and die young, and in which all are poor and cannot meet their basic needs, might be an equal one but it is still not a good one and, if it could be different, it is also unjust. Poverty is not unjust because others are richer but because people in poverty are not able to live a good life in the sense that they fall short of those central capabilities and functionings. To fulfil this task, it is necessary to specify the relevant capabilities and functionings but also the relevant thresholds that need to be reached. This opens the discussion about a list of central capabilities and functionings and their justification. Still, no method to select capabilities and functionings will be perfect and no list will be exhaustive. Justice should inform and guide the societal framework and the design of its institutions and for that it is neither necessary to draft a full list out of theory nor can empirical evidence be enough but such evidence has to be interpreted before the normative goals of justice. If we want to design justice in the context of the education system a more refined and tailored list of capabilities and functionings is needed than if justice is discussed on the level of a whole society. For the latter, I would view an orientation on the goal of justice to enable people to become and be autonomous and respected persons as a guiding principle.