This paper is a systems theoretic examination of Eugen Rosenstock-Huessy’s “cross of reality,” a structure that fuses a vertical spatial dyad of inner-outer and a horizontal temporal dyad of past-future into a space-time tetrad. This tetrad is compatible not only with the human-centered phenomenological point of view that Rosenstock-Huessy favors, but also with a world-centered scientific point of view. It is applied by him explicitly or implicitly to a wide variety of individual and collective human experiences. In this paper I mention a few examples of these applications from the realm of language, religion, and social critique. I also show that Rosenstock-Huessy’s tetradic structure accords with and diagrams some basic concepts in systems theory.