It is possible to understand EM as asserting a necessary truth about the composition of mental processes: that, necessarily, some mental processes are partly constituted by processes of environmental manipulation, etc. It is possible, but inadvisable. (Rowlands, 2009b, p. 54)But, this seems to be a direct assault on Revolutionary EC, as articulated by, for example, Menary:
The manipulation of external vehicles is importantly different from the manipulation of internal vehicles and their integration is the unit of cognitive analysis. We are not just coupling artifacts to pre-existing cognitive agents; the organism becomes a cognitive agent by being coupled to the external environment. (Menary, 2006, p. 342)It looks like Menary is defining cognition or offering a theory of what cognition is which makes it a necessary truth the cognition is extended.
Same goes if you read Clark and Chalmers as offering a definition, or theoretical account, of active externalism, (rather than a reason for it) in this passage:
We advocate a very different sort of externalism: an active externalism, based on the active role of the environment in driving cognitive processes (Clark & Chalmers, 1998, p. 7)Menary, R. (2006) Attacking the bounds of cognition. Philosophical Psychology, 19 329-344.
Rowlands, M. (2009) Enactivism and the Extended Mind, Topoi, 28:53–62.