The abstract democratic ideal is hegemonic nowadays, but, what is considered to be its concrete institutional forms are facing a growing “crisis of representation” and distrust. As an answer to this crisis and after centuries of absence, sortition (selecting representatives by lots) is making its return on the political stage through various academic research, practical experiments and activist claims. But each thinker, experimentation, or militant group, is giving a different explanation of what sortition is, why and how it could strengthen democracy. How could we be thinking sortition efficiently? Instead of doing a chronology of this return my proposal is to construct a more general theory of sortition in a comparative approach. A broad study seems necessary in order to grasp the theoretical constants, despite the empirical diversity of sortition concrete uses. First, I shall compare sortition to the three other selection modes: election, nomination and certification. Second, I will analyse the deliberative frameworks, that is to say “who decides what how”. Third, I will distinguish four democratic principles of sortition: equality, impartiality, representativeness and legitimacy. My first research hypothesis is that sortition is likely to offer a greater equality, impartiality and
representativeness. My second hypothesis is that sortition is the only method of selection producing a specific form, a humility-legitimacy when the three other
selection modes are producing a superiority-legitimacy.