The Extended Brain
Andy Clark and David Chalmers have proposed the “Extended Mind” thesis. This is the claim that there are things in the world, beyond our skull, like a notepad or a smartphone, that do not just help us think and remember, but should be considered as part of our mind.
Clark and Chalmers argue that
“beliefs can be constituted partly by features of the environment, when those features play the right sort of role in driving cognitive processes. If so, the mind extends into the world.”
In order to support this claim, they provide the examples of Inga and Otto, an Alzheimer patient. Inga can remember directions and find her way, just by using her brain. Otto, due to his condition, cannot do so completely autonomously but needs support in the form of a notebook. Clark and Chalmers then claim: “For Otto, his notebook plays the role usually played by a biological memory.” Since Otto’s notebook plays the “right sort of role”, the same role played by Inga’s brain, the notebook too can claim “epistemic credit”.
Similarly to Minsky’s definition of AI (we would call a program “intelligent” if it did things in a way that we would call “intelligent” if a human did them), they conclude:
“If, as we confront some task, a part of the world functions as a process which, were it done in the head, we would have no hesitation in recognizing as part of the cognitive process, then that part of the world is (so we claim) part of the cognitive process.”
In the text, it seems that for Clark and Chalmers “external” means “outside the skull”. In the history of philosophy the brain itself has often also been thought to be “external” and “part of the world” with respect to the mind, consciousness, subjectivity, etc.
Don’t Clark and Chalmers actually mean to speak of an “extended brain” rather than an “extended mind”?
It also seems that their distinction between internal and external elements is not sharp, but gradual. The extension seems to be a slippery slope. Clark and Chalmers discuss the reliability of coupling between the mind and its tools, whether they are always readily available or not:
“Counting on our fingers has already been let in the door, for example, and it is easy to push things further. Think of the old image of the engineer with a slide rule hanging from his belt wherever he goes. What if people always carried a pocket calculator, or had them implanted?”
This last suggestion is highly suggestive. Clark and Chalmers at various points mention “neural implants” from a “cyberpunk future”.
Due to the appeal to neural implants, the meaning of “external” now seems to shift, encompassing also things inside the skull and even inside the brain. This ambiguity and elasticity of “external” (vs mind or vs brain) suggest that the distinction is actually quite gradual.
Chalmers and Clark argue that
“In the distant future we may be able to plug various modules into our brain to help us out: a module for extra short-term memory when we need it, for example. When a module is plugged in, the processes involving it are just as cognitive as if they had been there all along.”
A scant 20 years later, the future is upon us: we have brain implants that redress disabilities and restore normal brain function. Such implants involve bio-hybrid technology: symbiotic integration of bioengineered brain tissue, neuromorphic microelectronics, and AI. Such devices further blur the distinction between “internal” (inside the brain) and “external” (outside the brain) extensions, while not touching the more principled distinction between mind and the physical world at large (including the brain).
So what exactly is being extended? From where and into what?
Perhaps it makes more sense to say that it is not so much the mind that is extended, as its symbolic tools.