For contemporary critical philosophers of education, the thought of Paul Tillich, a protestant theologian, does not seem to be a very likely point of reference. Nevertheless, we decided to read some of his works within a philosophical-educational context. Reading those works of Tillich we realized that they required a pedagogical-philosophical acknowledgement. Scarce as the educational analyses of Paul Tillich's writings are, they concern mostly either religious education or some specific issues connected with teaching. Our proposal was to read him differently: as a critical tool for grasping contemporary educational issues, independent from a religious or didactic approach. In the article, referring to the thoughts of Tillich, we analyze the three most important tensions of the last and present centuries: "kairos" I and II, referring to the human condition after World Wars I and II, and "kairos" III, related mainly to the war on terrorism and to the growing climate crisis. The analysis of these special moments in the history of humankind is related to the postulates and pedagogical attitudes articulated by us. We conclude that as a result of the deepening climate crisis and the looming specter of a cataclysm, the transition to a better "aion" may enable the pedagogy of radical hope. The essence of this pedagogy is to shape the "courage to be" during grassroots, collective and political action - an existential attitude saturated with resistance, concern and hope that such grassroots, cultural-religious practices can contribute to social change and reduce the fear of inevitable death associated with the risk of annihilation of the Earth.