K&F on the Differences between AC systems and Cognitive Systems

Next we want to probe Adams and Aizawa’s claim that extended cognitive systems are analogous with air conditioning systems. We think there are significant differences, which may decide the case in favour of extended cognition.  The components of the air conditioning system have come to perform their distinctive functions through design, not through development and learning.  Our brains, by contrast, learn to factor into their processing operations, external artefacts that have a place in our cultural practices.  Through development, the sorts of functional structures and representations that are constructed in our brains are geared into working in partnership with external resources.  These external resources become grafted into the workings of the internal neural circuitry so that at least some of our cognition can only be accomplished through the symbiotic partnership our brains have formed with their cultural environs.  The inner only assumes the form it does, and works in the way it does because it is encultured, forged and moulded by the many different activities it repeatedly and regularly engages during the course of development.   The biological internal components of an extended cognitive have developed to work in partnership with the external, cultural components. Our minds are hybrid minds. (Kiverstein and Farina, forthcoming, p. ???)

Ok.  Everything in the third sentence and thereafter (except maybe the last sentence) seems to me to be correct.  But, how does any of that show that cognitive processes pervade the whole of the cognitive system?

Suppose that the human digestive system has evolved to process cooked food.  Would that show that digestion extends into the environment?

Suppose that an individual's digestive system adapts to enable that person to be able to digest alcohol more efficiently.  Would that show that digestion extends into the environment?

Suppose the digestive system only assumes the form it does, and works in the way it does because it is encultured, forged and moulded by the many different activities it repeatedly and regularly engages during the course of development.  Would that show that digestion extends into the environment?

I'm not buying.