First, consider the bonobo Kanzi's planning, thinking, and decision making that utilizes a 256-symbol keyboard, which Kanzi has, over the years, learned to use to communicate his beliefs and desires. Bonobos in the wild surely have desires (e.g., for bananas), but just as surely they don't have the kind of sophisticated, cooperative desires that Kanzi expresses, such as the desire to be taken by a particular person to a sequence of locations, or to do one activity first and then another. What the symbol board has done is to reconfigure Kanzi's capacity for belief and desire, much as our using pen and paper reconfigures our mathematical ability by augmenting the in-the-head capacity we have for multiplication. Both are cases in which an external symbol system becomes integrated with preexisting cognitive capacities in ways that significantly modify the nature of those capacities. We can, of course, distinguish between the parts of those capacities that are internal and those that are not, but this is already to concede that the overall cognitive process itself is extended. (Wilson, 2010, p. 180).
I'm going to guess that lodging a bullet in the brain would reconfigure Kanzi's capacity for belief and desire. And it would be pretty well integrated with preexisting cognitive capacities in ways that significantly modify the nature of those capacities. But, I wouldn't want to say that Kanzi's cognitive processes extend into the bullet. (Maybe it would be a cognitive resource, but regarding that idea see my post on "Cognitive Resources".)
This looks to me to be just a thinly veiled version of the coupling-constitution fallacy. To reconfigure is to have a certain kind of causal influence. To be integrated is to have a certain kind of persistent causal influence.
Maybe Wilson could add, following Clark, that the reconfiguring, integrated thing has to be an information processing resource. How about embedding a measuring tape in Kanzi's brain? (Maybe that would be a cognitive resource, but ... see above.)
Well, maybe, if the measuring tape were integrated in the right way in the overall information processing economy of Kanzi's brain, then cognitive processing would extend into it. If, by this, Wilson means that, were the measuring tape to bear non-derived content and be manipulated in particular sorts of ways characteristic of cognitive processing, then yes. That's the Adams and Aizawa view. Our point is that such reconfigurations and integrations do not typically lead to the right sorts of information processing economies. But, in any event, this line does not seem to be the sort of reconfiguration and integration Wilson has in mind, since he doesn't mention them.