Properly speaking, "inertia" is resistance to change. At the same time, if we think of culture as moving through time and space between individuals, inertia is the tendency of that culture to continue moving at the same rate unless other forces act upon it. Counting inertia in this way as a kind of inherent tendency or "force," I offer illustrative evidence in this paper for three additional classes of force: entropy, interest, and metaculture. I show that these forces operate at the level of micro-processes of discourse replication, as well as in larger-scale phenomena. The force of interest is the foundation for economic theory and its law of supply and demand, but it can be glimpsed as well at the microlevel in narrative replication. However, taken alone it provides an incomplete and distorted account of cultural motion, which takes place not only at the behest of inertia, but also in response to reflexive cultural processes grouped here under the heading of "metaculture." The latter can be glimpsed at the micro-plane in self-correction within narration or in instructional correctives, but it operates as well on a large scale in ideological formations such as modernity and the emphasis on newness.