By Stephen Beale, Catholic Exchange - According to Catholic theologian Erich Przywara, there are four such terms: kerygma, mysterium, kairos, and oikonomia (a framework that he has adopted from another theologian, the Lutheran philosopher Paul Tillich, reworking it according to the Thomistic tradition). Put simply: kerygma refers to the proclamation of the gospel; mysterium involves those things which are hidden; kairos is God’s timing; and oikonomia concerns God’s dispensation or administration of things.