Monday, March 9, 2009

The Extended Mind

The Extended Mind
In their essay “The Extended Mind” (1998), Andy Clark and David J Chalmers attempt to answer the question “where does the mind stop and the rest of the world begin?” This may, in fact, be a misleading question, simply due to human preconceptions about the meaning of the word “mind” and the readiness with which we view it as interchangeable with the word “brain”. A more truthful, or comprehendible, explanation of their thesis would be: an attempt to better understand the boundaries of individual cognition. While most of us can readily understand the hypothesis that individual cognition ends where the brain ends, with the clear delineation of skull and skin, Chalmers and Clark also reference the lesser know hypothesis of semantic externalism.

Semantic Externalism and the Twin Earth Thought Experiment
Semantic externalism is a theory initially proposed by Hilary Putnam in his essay “The Meaning of ‘Meaning’” (1975); this idea was subsequently expanded on by Tyler Burge in his 1982 essay, “Other Bodies”. In his essay, Putnam asks us to imagine a parallel universe exactly the same, in every way, to our own. In this parallel universe “Twin Earth” would exist as indistinguishable from our own Earth, except for one small difference. What the inhabitants of “Twin Earth” refer to as “water” is not H20 it is, in fact, a more complex formula, referred to, within “The Meaning of ‘Meaning’,” as XYZ. Superficially, however, XYZ is also indistinguishable from H2O. Putnam is careful to note that this experiment should be set a few centuries in the past so that neither the inhabitants of Earth nor the inhabitants of Twin Earth would be capable of understanding the underlying chemical differences between the two.

Putnam’s conclusion, therefore, in the Twin Earth Thought Experiment is that the brain is incapable of processing the entirety of meaning and that certain meanings exist entirely outside the human mind (as completely external). Therefore, semantic externalism is the theory that, as Putnam so eloquently put it, “meaning ain’t all in the head”.

Active Externalism
Clark and Chalmers are quick to distinguish their own theory of active externalism from Putnam’s, then, better known theory of semantic externalism. They also note that while the two theories are extremely different from one another, one does not necessarily preclude the other. They explain this distinction by asserting that a person’s understanding of the word “water” is based on their historical experience of water and therefore, has “no role in driving the cognitive process in the here-and-now.” Active externalism on the other hand, describes a coupling of the human organism and some external features which “play a crucial role in the here-and-now”. It is this coupling of the human organism and the external environment that composes extended cognition.

Extended Cognition
Extended cognition challenges the idea that thought is limited to the brain. To clarify, Clark and Chalmers assert that rather than taking a metaphorical picture of our environment and then considering it internally “in our heads” our internal picture is actually very limited (consider the Daniel Simons attentional focus demonstration referred to in the article “Why Google is Making Us Smarter”) and that we must constantly refer back to our environment in order to draw on the information needed for our specific purposes.

If we are playing a game of Tetris, for instance, we do not imagine the falling shape in its correct position before pressing the button to rotate it. We press the button and rotate the shape in order to figure out what the correct position would be. Pressing the button, therefore, is an epistemic action or an “action [that] alter[s] the world so as to aid and augment cognitive processes such as recognition and search.” This distinguishes it from pragmatic actions, which are taken to fulfill their own isolated purpose.

Pressing the button becomes part of our cognitive process, therefore, not separate from it. Thus our cognition extends beyond our brains to include the button. Together, our brains and the button form a coupled system which, Clark and Chalmers argue, is a “cognitive system in its own right.” If, they contend, we would have no problem considering something part of the cognitive process were it done in the head then we should have no problem considering it part of the cognitive process at all.

Extended Belief
Extended belief takes the assertions of extended cognition and active externalism one step further. If someone keeps information written in a notepad can that information be seen as his or her belief? Clark and Chalmers have compiled a checklist of criteria necessary to define information contained within an external source as extended belief.
1. Consistency – the external source of information must be a constant in the life of the agent.
2. Accessibility – the external source of information must be readily accessible with little effort on the part of the agent.
3. Reliability – the agent must readily endorse the information provided by the source.
4. History – the agent must have endorsed the information provided by the source in the past. (Clark and Chalmers note that this fourth criterion for extended belief is arguable)
Although they do not mention it as one of their criteria, portability is mentioned as a criterion earlier in the essay. It is possible that portability is an obvious criterion for achieving accessibility.

Wrapping It Up

While the theory of the extended mind might seem flighty, an interesting subject to ponder at best, it actually has a great deal of applicability in the study of cognition. Clark and Chalmers are quick to note that the distinction that they make is not simply terminological. Clark has gone on to write a book called Natural Born Cyborgs which is centered on the idea that our current use of coupled systems and the readiness with which the brain adapts to using new tools to aid its cognitive processes all point to a very real future wherein the delineations of organic and artificial intelligence become increasingly fuzzy. Clark and Chalmers note how significant an understanding of the extended mind could be. “… explanatory methods that might once have been thought appropriate only for the analysis of "inner" processes are now being adapted for the study of the outer, and there is promise that our understanding of cognition will become richer for it. “

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