Intrinsic content, active memory and the extended mind

Clark and Chalmers (1998) defend the view that the human mind need not be in the human head.To speak more carefully, they defend the view that the material vehicles 1 of cognition can be spread out across brain, body and certain aspects of the physical environment itself.Critics of this view (which has become known as the 'extended mind hypothesis', henceforth EM) have pointed to the supposedly intrinsic nature of the contents carried by inner biological vehicles.External, non-biological vehicles, such critics claim, are not (at least in any typical human case) similarly endowed, and thus fail to exhibit one of the key 'marks of the cognitive' (Adams and Aizawa 2001: 48).I shall argue that this response is mistaken.First, though I shall not dwell upon this, it is unclear that there is any such thing as intrinsic content anyway.Second, in so far as the notion is intelligible at all, there is no reason to believe that external, non-biological structures are incapable of supporting such content.And third, even if they were incapable of so doing, this would not actually compromise the case for the extended mind.The worry about intrinsic content, I conclude, is multiply fatally flawed.Despite all this, there are some related and legitimate worries that may well be informing the unease expressed by Adams, Aizawa and others. 2The paper ends by briefly discussing these worries, pointing to a possible solution, and then gesturing at the larger picture of the extended mind and its place in nature.The original argument for EM took the form of some thought experiments, a principle meant to command rational assent, and a battery of 1 It is important, in considering the issues to be discussed, to maintain a distinction between vehicles and contents.Possessing a contentful mental state is most plausibly a property of a whole active system (perhaps in some historical and/or environmental context).Within that system, certain enduring material aspects may play a special role in enabling the system to possess (whether occurently or dispositionally) a given mental state.These material aspects are the vehicle of the content.The Extended Mind hypothesis is really a hypothesis about extended vehicles, vehicles that may be distributed across brain, body and world.We conflate vehicles and contents, as Dennett (1991) and Hurley (1998) stress, at our philosophical and scientific peril. 2 Some related critical treatments include O' Brian 1998, Dartnall (in press) and Weiskopf (submitted).For a somewhat different critical angle, see Sterelny (in Press).