The comparative approach
Throughout his critical analysis of the welfarist approach (see, in particular, Sen 1979a, 1979b), Amartya Sen suggested assessing social situations by considering quality of life rather than just utility or wealth.
He developed the bases for the “comparative approach” in general and the illustration of what it could be, the capability approach, notably in his first Tanner lectures published in 1980 and his Hennipman lecture published in 1985 (see also Sen 1987, 1992, 1993). It constitutes an intermediate response to the debate on “equality of what?” which opposes welfarist approaches to resourcist theories. It provides rankings of situations based on explicit criteria of justice, and considers objective descriptions of life situations as relevant information to capture quality of life, that is, an index of individual welfare as an “individual basis for justice”. On the one hand, utility, says Sen among many other critics, is too sensitive to adaptation, and, on the other hand, resources do not pay attention to the particular individual ability to transform commodities into well-being. Quality of life may hence be better captured with functionings, which Sen (1985: 6-7) defines as “what the person succeeds in doing with the commodities and characteristics at his or her command.... It is an achievement of a person: what he or she manages to do or to be”.At any moment, according to his or her situation, tastes, or life plans, a person may choose some particular functioning among the capability set. Capabilities are “the various combinations of possible functionings a person can achieve and from which he or she can choose one collection” (Sen 1985: 9). The wider this set is, the more the individual is free to choose between different lifestyles. The use of capabilities as an informational basis to assess quality of life therefore focuses not only on the role of commodities in generating well-being, taking into account individual’s specific ability to transform commodities into well-being, but also values for itself the freedom to choose their lifestyle.
There remain two technical remarks and one further discussion. First, as far as this information is objective in the sense that they are observable and measurable on a common scale, interpersonal comparisons are meaningful (Baujard 2011) so that the latter are justified and well accepted in this context. Secondly, the assessment of capabilities is based on some valuation of lists of different functionings, themselves being a vector of achieved doings and beings. Such multi-dimensionality is likely to cause moral dilemmas in certain situations, hence to generate substantial incompleteness. For instance, what if I have more health but less education or social relations? A possible answer, specific to Sen, is to accept that rankings of social states may be incomplete. He does not consider incompleteness as a relevant problem in the context of normative issues (see, notably, Sen 2009). Another approach is to gather the functionings into an index by weighting them according to their importance (Robeyns 2005a). Thirdly, the crux of the debate opposing these two different philosophical capability approaches lies in the question of operationalization (on this opposition, see Robeyns 2005b; Baujard 2007). Following Aristotle, Martha Nussbaum believes that there is a single notion of the human good, virtues and flourishing life (Nussbaum 1988, 1993). This leads to the proposition of a concrete and comprehensive list of functionings, so that the approach belongs to fundamental universalism. Operational applications are therefore implementable for scientists (Alkire 2002; Robeyns 2006). The fact that values and weighting are determined by scientists rather than by the individuals themselves explains why this approach is often criticized for its paternalism. In contrast, Sen’s position meets certain relativism, in order to give to public deliberation the main role in a democracy. Therefore, he refuses to provide a clear list of functionings which could measure well-being for everyone on a common scale. It is therefore difficult to implement a mere application of Sen’s capability approach since it fundamentally relies on public debate. The latter is the only legitimate place to decide which moral values should be at stake, hence the retention of specific lists of functionings and, eventually, measurement of capabilities.
The extremely extensive literature on the capability approach, at least since the 2000s, is but a multi-dimensional analysis of living conditions, for which the United Nations Development Programme (UNDP) human development index (HDI) is only one very rough illustration. As the approach was generalizing, it has lost its specificity, which was to pay special attention to the value of freedom, understood as the possibility for everyone to live the life they have reasons to value.