Philosopher Alexander Max Bauer investigates to what extent people's needs must be covered in order for the society to perceive a distribution of goods as fair. His latest study focuses on the distribution of housing space.

Housing is in short supply in Germany, especially in the cities. Young families in particular have a hard time finding affordable accommodation. What makes this problem interesting for a philosopher?

Bauer: Questions of justice are a classic topic in philosophy. In addition to need-based distributive justice, other forms such as merit-based justice, opportunities-based justice, and the principle of equality, with all of which needs-based justice may sometimes be in conflict, are relevant. The principle of merit-based justice dictates that a distribution of goods is fair when the amount an individual receives corresponds to their contributions and performance. The principle of equal opportunities focuses on ensuring that all members of society have the same opportunities, say, for success. The principle of equality – in its simplest form – can mean that all individuals possess the same amount of goods, for example the same amount of money. And a need-based distribution exists when each individual is provided with sufficient goods to at least cover their basic needs. Housing is an ideal topic for research into questions of justice because it is something that everyone needs. This is why it's such an exciting topic for me as a philosopher.

In your most recent study, the participants were asked to rate the fairness of various fictitious distribution-of-living-space scenarios. Can you explain your methodology?

We divided the study participants into two groups and told the first group that the living space needs were the same for all households: 1,000 units – a fictitious figure. The respective "parliament" had a free hand in deciding how much living space it would provide. We presented the same story to the control group, but without mentioning the living space needs. Then we analysed the relationship between the extent to which different allocation scenarios met living space needs and the respondents' perception of how fair each of the allocation scenarios were. In total, we tested eleven scenarios on each of the two groups.

How did the scenarios differ from each other?

In terms of the amount of living space that the parliament made available to each household. For each of the eleven scenarios, the number of allocated units increased by 200, starting at zero and going up to a maximum of 2,000 per household. In the first scenario, the parliament didn't provide any living space at all, in the second scenario it gave each household 200 units, and so on. We gave the two groups the same two tasks for each of these scenarios. In the first task, participants were asked to rate all eleven scenarios on a scale from zero percent (not fair at all) to 100 percent (completely fair). In the second task, we presented them with two adjacent allocation scenarios and asked them to rate whether or to what extent the level of fairness between the two differed.

Apparently, an awareness of needs influences the extent to which people perceive the distribution of a particular resource to be fair.

And what was the key finding of the study?

If we look at the aggregated figures, we see that the perception of fairness among participants in the control group increased in proportion to the amount of living space allocated to each household, whereas in the group of those who were informed about the specific needs, the perception of fairness rose sharply around the 1,000-units mark. So apparently an awareness of needs influences the extent to which people perceive the distribution of a particular resource to be fair. The analysis of the second task confirms this. Participants in the group that was aware of needs rated the allocation of 1,000 units as considerably fairer than that of 800 units. For most of the other comparison pairs, however, the differences were only minor and similar to the results for the control group. If we take a look at the underlying individual assessments, it becomes clear that this aggregated result is based on a complex system of different ideas of justice, which become relevant if provided with needs information.

Did you find anything surprising about the results?

We were surprised to see how strongly participants from the group that was informed about needs gravitated towards the figure of 1,000 housing units and perceived it as so much fairer than one which was only slightly lower. Much of the research literature postulates that the first units of a good will be particularly beneficial to individuals – in our example, a very small flat would still be significantly better than homelessness. Consider the law of diminishing marginal utility, which states that as the quantity of a good increases, the marginal utility of that good decreases. For many of the participants in this group, however, this did not appear to apply.

You conducted the study in an interdisciplinary team made up of researchers from the fields of philosophy, economics and psychology. Do you often work with representatives of other disciplines — and what are the advantages of this approach?

For a long time, academic philosophy was more a science for lone wolves, with people working on their own in quiet little rooms. In some areas, this is still the case today. But by the turn of the millennium a new trend had emerged, and in philosophy too, interdisciplinary work has become increasingly common since then. Many areas are now "empirically informed", and we're also adopting more and more empirical methods from other disciplines and conducting our own experimental research. We call this relatively new trend "experimental philosophy". In this study, we bring together both the empirical-experimental aspect and the interdisciplinary approach. This is by no means an easy undertaking. Each science has its own code, its own terms, concepts, and assumptions, so you first have to find a common language. The advantage lies in being able to combine different approaches and methods. Everyone looks at the same problem from a slightly different perspective and no one fully comprehends it on their own, so it makes sense to discuss the different perspectives together and get a more comprehensive picture. And ultimately this external perspective is also immensely helpful when it comes to reflecting on your own assumptions.

We see from this and other studies that for many people, in addition to merit-based justice and equal opportunities, need-based justice is also important.

What conclusions have you drawn from the results?

We see from this and other studies that for many people, in addition to merit-based justice and equal opportunities, need-based justice is also important. In another study, for example, we had participants allocate firewood to fictitious individuals who needed it to heat their homes. Some of these individuals were described as hard-working while with others the need for support was self-inflicted. But even though their dependence was due to lacking motivation rather than illness, disability, or other factors beyond their control, many study participants nevertheless gave them the necessary amount of firewood. Such findings – as with the housing study –show that for many people need is an important criterion when it comes to determining what is fair.

What can politics and society learn from this?

The idea that basic needs must not go unmet, regardless of an individual's contribution, is one of the fundamental principles of our welfare state – and is closely linked to the philosophical concept of dignity. Although our studies are not statistically representative, they are an indicator that people want guarantees for this dignity. Consequently, when certain political actors call social welfare into question, or even call for it to be completely abolished "in certain cases" and for all needs to be ignored, they are treading on very hazardous terrain.

Interview: Henning Kulbarsch