Abstract
Psychotherapy is concerned with the well-being of clients. However, most models of
psychotherapy operate without an explicit model of well-being. In the context of positive
psychology, two theories of well-being have been developed and applied to psychotherapy:
Martin Seligman’s “well-being theory”, which has inspired positive psychotherapy, and Carol
Ryff’s “six-factor model of psychological well-being”, which has inspired well-being therapy.
In the context of philosophy and the social sciences, Amartya Sen and Martha Nussbaum have
developed the capability approach as a framework that is directly preoccupied with well-being.
Nonetheless, the capability approach has yet to be applied to psychotherapy. In this thesis I
present the current literature on well-being in the capability approach and in positive
psychology. I then explore two questions. The first question addresses how positive psychology
and the capability approach conceptualize well-being, both in terms of philosophical
underpinnings and how they employ the concept of well-being. The second question considers
how the capability approach could be integrated into psychotherapy. Regarding the first
question, I argue that the positive psychology theories of well-being are currently misclassified
in the literature as eudaimonic theories, while the capability approach should be viewed as an
objective list theory of well-being. I also argue that the positive psychology theories of wellbeing are about well-being narrowly construed, while the psychotherapeutic models they
inspire are arguably about well-being broadly construed. The capability approach does not seem
to be committed to a single sense of the concept of well-being. I then argue that commitment
to well-being broadly construed is preferable for psychotherapy. Regarding the second question
explored in this thesis, I suggest that capabilitarian accounts of well-being can complement
different psychotherapeutic models by ways of: 1) informing views on well-being; 2)
contributing to clinical interviewing and goal setting; and 3) informing case formulation
alongside existing approaches. The proposed interactions between the capability approach and
psychotherapy provide clues about ways that well-being can be explored by future theoretical
and empirical research.