The present article introduces the theory of cultural evolution as a possible basis for treating language as a selection process. Cultural evolution is often thought to be Lamarckian, involving the transmission of explicit concepts. A possible complementary neo-Darwinian principle operating in the social realm is defined in terms of the tacit knowledge that underlies explicit concepts. Since some forms of tacit knowledge cannot be adapted, a neo-Darwinian principle of cultural evolution is established. This is attractive because Lamarckian selection is plagued by a problem of maintaining stability in the face of individual-level adaptation. A statistical argument is presented, indicating that this problem requires the need to protect the Central Dogma in its wider form, also when language is treated as a selection process. In the course of the argument a definition is provided of the replicating cultural code that aims to clarify previous definitions. The usual “memetic” definition of interactors is also reconsidered in order to open the possibility of explanations with a causal structure equivalent to the neo-Darwinian or Lamarckian explanations.