The correspondence of 1948 between Karl Popper and Michael Oakeshott, translated for the first time in Italian and published in the appendix to this paper, demonstrates the existence of two different ways of thinking about politics: the rationalist approach, founded on the “argumentation” as a rational means for the non-violent solution of problems (Popper), and the traditionalist mode, inspired by the method of “conversation” as a guarantee of constant openness to the diversity of identities (Oakeshott). To rise from the letters is a mutual influence on the interpretation of the key concepts that characterize the thought of the two authors, which however does not cancel the fundamental divergence of their political orientation.