This two-part article presents the research program for a theory and empirical analysis of religious evolution. It is assumed that religion isprimarilya co-evolution to societal evolution, which in turn is a co-evolution to mental, organic, and physical evolution. The theory of evolution is triangulated with the systems theory and the semiotically informed theory of communication, so that knowledge can be gained that would not be acquired by only one of the three theories: The differentiation between religion and its environment can (...) be reconstructed based on the theory of evolution. The elements of the theory of evolution can be understood as the formation of systems. The semiotically informed theory of communication clarifies the conditions of the combination of both the systems theory and the theory of evolution as well as its objects. In turn, the combination of the systems theory and the theory of evolution can describe how communication—including religion and science—evolves and is structured. (shrink)