Here's the kind of thing they tend to say:
Is the mind contained (always? sometimes? never?) in the head? Or does the notion of thought allow mental processes (including believings) to inhere in extended systems of body, brain and aspects of the local environment? The answer, we claimed, was that mental states, including states of believing, could be grounded in physical traces that remained firmly outside the head.
What does someone have in mind when she thinks of inherence? Dictionaries tell us that 'inherence' in metaphysics means "the relation of attributes, elements, etc, to the subject of which they are predicated, esp if they are its essential constituents". Well, we predicate thoughts and feelings of people, not of brains or parts of the local environment, so that doesn't help us here. Or it ends the discussion too soon, since those who know how to use the word 'person' properly distinguish people from their peri-personal environs (the clue's in the words 'peri' and 'environs').
A side is predicated of a triangle, happiness of a happy man, and legs of a chair. What does it mean to say that the same relation is enjoyed by all of these? Or that happiness 'inheres in' the happy man, the chair leg 'inheres in' the chair? The answer I propose is simply that inherence obtains whenever the attribute or element in question is properly predicated of the subject in question - that (in other words) it truly is 'of' it. To return to the above extract, can 'believings' (whatever they are - I suppose they're the moments of our coming to our beliefs) inhere in the body, brain, or local environment? Well, no, not on this understanding of 'inhere' - since it's only people (or certain animals), and not their parts nor features of their peri-personal environments, that can come to believe anything. (And mental processes just aren't properly predicated of our organs; to think thus is just to commit the mereological fallacy.)
|In Defense of Otto
The authors of the above-quoted extract tell us "yes, sometimes", and this in part relies on their suggestion that the sense in which the information is stored on the shopping list is the same as that in which information is stored in the brain of he who does not rely on a shopping list. But what now does it mean to say that information is stored in the brain? It's not as if we store anything in our brains, in any normal sense of 'store' (as when we talk of a drugs mule storing cocaine up his butt). All it means here, I suggest, is that having a brain is causally necessary for retaining and recalling what one needs to buy from the shop (so that destroying some part of the brain will also result in the memories being lost). And for some people - forgetful people like me - a shopping list is equally necessary.
So shall we now say that the answer is 'yes, we can make sense of the idea of the extended mind, and it seems a highly plausible idea'? Well... no. For it's news to nobody that some of us need shopping lists to get the right things from the shop. What motivated the extended mind pundit was not the notion that our need of shopping lists can be equal to our need of brains when it comes to getting the right produce. What motivated her was rather the idea of thought equally inhering in, being grounded in, being realised in, supervening on, residing in, brains and shopping lists... and we've still not arrived at any clear idea of what that is. The only clarification of some such relation that got us anywhere pertained to grounding, and in the sense of 'grounding' that then became clear, our recollections are properly said to be grounded neither in the brain nor in shopping lists.
This is why it seems to me that the thesis of the 'extended mind' ultimately amounts to nothing. Not, to reiterate, because really the mind is all safely stashed away in the head. But rather because we've not yet had a sense of 'stashing' ('being realised in' etc.) be put on our conceptual table that does any meaningful work, whether we're envisaging it to obtain only inside or also outside the head.