Commentary: social capital, social class, and the slow progress of psychosocial epidemiology

their effort to clarify the theory underlying the use of ‘social capital ’ in social epidemiology.1 This is one of the ways in which scientific knowledge advances. Particular credit is due to Richard Wilkinson and his US collaborators2,3 for rescuing the income inequality hypothesis, promoting genuine social constructs and generating a series of heuristic hypotheses on the relationships among income inequality, social cohesion, and health. Robert K Merton has pointed to this type of creativity as one of the engines of disciplinary progress. That is, contrary to the conventional wisdom,4 criticism is not the only engine of disciplinary advance; indeed, an excess of criticism thwarts the development of innovative methods, concepts and models. It is harder to launch innovative hypotheses, as Wilkinson and his collaborators did a few years ago,2,3 than to criticize them. However, criticism is also an essential part of scientific progress.4,