The building of informational bases of judgment must be considered as a key issue for research on deliberative democracy. Usually, research on that issue focuses on the optimal rules that could achieve fair intercommunication between participants. But such focus neglects that who chooses the knowledge basis, which has to be taken as relevant, is in a position for predefining the kinds of outcomes of the deliberative process. This is precisely what can be observed in governance mechanisms like the European method of coordination. How to democratically build a knowledge basis, both fair and efficient, to assess capabilities? And how to place capabilities at the core of public policies? Such an undertaking implies the active participation of people to knowledge building, through processes of deliberative inquiry, able to transform their practical experience into general knowledge relevant for fair collective choices. The contribution explores what legitimate claims people can formulate with regards to knowledge building and what rules, possibly, such processes could follow. only subscribers can see the full article