Wellbeing, Freedom and Social Justice The Capability Approach Re-Examined, 2017a

3. Clarifications
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There are at least four terminological issues that need to be noted:
(1) ‘capability’ understood as a single opportunity versus ‘capability’
understood as an opportunity set; (2) Nussbaum’s more complex
terminology; (3) the quite different meanings given in the literature
to the term ‘basic capabilities’; and (4) additional refinements — both
some that have been proposed in the literature, as well as a proposal
that I will put on the table, namely to take the robustness of a capability
into account. Let’s look at these four issues in turn.
capability as an opportunity set
Let us first look at Sen’s original terminology. The major constituents
of the capability approach are functionings and capabilities. Functionings
are the ‘beings and doings’ of a person, whereas a person’s capability
is “the various combinations of functionings that a person can achieve.
Capability is thus a set of combinations of functionings, reflecting the
person’s freedom to lead one type of life or another” (Sen 1992a, 40).
According to Sen, a person has only one capability (or capability set),
which consists of a combination of possible, reachable functionings.
A person’s functionings and her capability are closely related but
distinct, as the following quote illustrates:
A functioning is an achievement, whereas a capability is the ability
to achieve. Functionings are, in a sense, more directly related to
living conditions, since they are different aspects of living conditions.
Capabilities, in contrast, are notions of freedom, in the positive sense:
what real opportunities you have regarding the life you may lead. (Sen
1987, 36)
Sen thus used the term ‘a capability’ for what we could also call ‘a
capability set’. The advantage of each person corresponds to one
capability (hence ‘a person’s overall freedom to do the things they want
to do and be the person they want to be’). In the original terminology,
each person had one capability, and the use of the word ‘capabilities’
therefore had to refer to the capabilities of various persons.
In Sen’s original terminology, a person’s capability consisted of a
range of potential functionings, out of which a particular combination
of functionings could be chosen. Functionings could therefore be either