Abstract

Much of the literature directed at the Extended Mind Thesis has revolved around parity issues, focussing on the problem of how to individuate the functional roles and on the relevance of these roles for the production of human intelligent behaviour. Proponents of EMT have famously claimed that we shouldn’t take the location of a process as a reliable indicator of the mechanisms that support our cognitive behaviour. This functionalist understanding of cognition has however been challenged by opponents of EMT [such as Rupert ; Adams & Aizawa ], who have claimed that differences between internal, biological processes and putatively extended ones not only exist but are actually crucial to undermine the idea that inner and outer are functionally equivalent. This debate about how to individuate the functional roles has led to a treacherous stand-off, in which proponents of EMT have been trapped under the persistent accusation of causal/constitution conflation. My strategy for responding to this charge is to look precisely at those functional differences highlighted by critics of EMT. I reckon that extended cognitive systems are endowed with quite different properties from systems that are “brain bound” and argue that it is precisely these differences that allow human minds to transcend their biological limitations. I thus defend a complementarity version of the extended mind, according to which externally located resources and internal biological elements make a different but complementary contribution to bringing about intelligent behaviour [Sutton ]. My defence of complementarity is based on both the phylogeny and the ontogeny of cognitive systems. I initially explore the interrelation between brain and cognitive development from a neuroconstructivist perspective [Quartz & Sejnowski ; Mareshal et al. ] and then argue that our brains do not have fixed functional architectures but are sculpted and given form by the activities we repeatedly engage in. As a result of repeated engagements in socio-cultural tasks, relevant brain pathways undergo substantial rewiring. Development thus scaffolds our brains, which become geared into working in symbiotic partnership with external resources. [Kiverstein & Farina ]. On these grounds, I call into question any tendency to interpret the human biological nature as fixed and endogenously pre-determined and side with proponents of DST [Oyama ; Griffiths & Gray ] and ontogenetic niche construction [Stotz ] in arguing that we should think of natural selection as operating on whole developmental systems composed of living organisms in culturally enriched niches. [Wheeler & Clark]. Complementarity defences of EMT argue that many of the kinds of cognition humans excel at can only be accomplished by brains working together with a body that directly manipulates and acts on the world [Rowlands ; Menary ]. I take Sensory Substitution Devices as my empirical case study. SSDs exploit the remarkable plasticity of our brains and with training supply a novel perceptual modality that compensates for loss or impaired sensory channel. I argue that the coupling with these devices triggers a new mode of phenomenal access to the world, something I propose to label as a kind of “artificial synaesthesia [Ward & Meijer ].This new mode of access to the world transforms our cognitive skills and gives rise to augmented processes of deep bio-technological symbiosis. SSDs therefore become mind enhancing tools [Clark ] and a perfect case study for Complementarity. Having shown the relevance of SSDs for EMT, I then take up the possibility that these devices don’t just relocate the boundaries of cognition but may also stretch the bounds of perceptual awareness. I explore the possibility that perceivers using SSDs count as extended cognitive systems and therefore argue that the experiences they enjoy should be counted as extended conscious experiences.[Kiverstein & Farina, ]. SSDs are quite often said to involve some form of incorporation.[Clark ]. Rupert has challenged this idea and its relevance for EMT on the grounds of his embedded approach. Particularly, he has explained tool-use in terms of the causal interaction between the subject and its detached tool. In the final chapter of my dissertation I critically look at his objections and argue that all his arguments fail to apply to SSDs. In SSD perception in fact the tool becomes geared to work in symbiotic partnership with the active subject and then get factored into its’ body schema so that both of them come to form a single system of cognitive analysis.