The motor system controls what it senses

marshalling the free variables into coherent functions. Quadruped gait may be an example: when one stable movement pattern is driven beyond a critical value on a system-sensitive parameter, a bifurcation occurs and a new spatiotemporal pattern a new stability arises. In such a view, no explicit "gait selection" process is required (e.g., Gallistel 1980). To reiterate our main point, however, in the perspective offered here, order (control and coordination) is functionally specified in the system's dynamics. The radical claim, as Gibson (1979) once remarked, is that behavior is regular but there are no regulators. A less radical statement would be an affirmative answer to Yates's (1980) question to the readers of the American Journal of Physiology: Do [you] know of a serious effort to discharge the homunculus? The spirit of the foregoing discussion leads us to raise one final issue. It is the growing intuition stemming from theoretical considerations raised here and elsewhere (cf. Anderson 1972) that the problem of order in natural systems might be attacked more effectively by seeking out a single set of physical principles that can apply at all levels, rather than by positing different units of analysis at each level. One assumes that nature operates with ancient themes. In this commentary we have tried to provide the flavor of the ones that neuroscience in general, and the field of motor control in particular, might consider worth orchestrating.