Continuity in Question: Linguistic Competence and the Extended Mind

1. Continuity in Question: Linguistic Competence and the Extended Mind Michael Wheeler Department of Philosophy University of Stirling

2. The Extended Mind • One species of recent thinking about the mind stresses its extended (over brain, body and world) character • A (the?) key supporting argument: the Parity Principle (PP) • “[Under certain conditions, the] organism is linked with an external entity in a two-way interaction, creating a coupled system that can be seen as a cognitive system in its own right. All the components in the system play an active causal role, and they jointly govern behavior in the same sort of way that cognition usually does. If we remove the external component the system’s behavioral competence will drop, just as it would if we removed part of its brain. Our thesis is that this sort of coupled process counts equally well as a cognitive process, whether or not it is wholly in the head.” (Clark & Chalmers, The Extended Mind) • So the real-time mind is (sometimes) an extended mind

3. Understanding the Parity Principle: Part 1 • Despite C&C’s formulation of PP, the claim is not (should not be!) that external factors count as themselves the proper parts of a cognitive process by being coupled in a particular way to an already existing cognitive agent or cognitive system • Rather, the claim should be that internal and external elements can, in certain circumstances, be integrated parts of a single causal system that itself counts as a cognitive system (Menary)

4. Understanding the Parity Principle: Part 2 • And the claim is not (should not be!) that there are no differences between the ‘wholly inner’ and the ‘outer-element-involving (in the right way)’ versions of some cognitive capacity (e.g., of memory), but rather that what differences there are aren’t relevant to the status of the outer elements in the second case as themselves the proper parts of a cognitive process • How to make this stick: inner and outer factors may qualify as the proper parts of a cognitive process, given an account of ‘the cognitive’ that does not assumeeither set of factors (inner or outer) to be privileged with respect to fixing what counts • PP, correctly understood, is in fact a straightforward consequence of functionalism in the philosophy of mind

5. How does the Extended Mind Perspective (EM) Earn its Keep? • Taking orthodox cognitive science – classical and connectionist – as the default position, adopting EM ought to compel us to change our view of the kinds of inner mechanisms involved in real-time intelligence. But how? • What EM does is out-source complexity to the environment • So (a) the inner states and mechanisms involved will be leaner and more closely coupled to their environments, and (b) less explanatory weight will be placed on the construction and maintenance of inner representations • Canonical examples of good EM practice: • Franceschini et al.’s fly-robot • Rumelhart and McClelland on long multiplication. So cognitive extension often involves material symbols (= symbols and systems of symbols – including those of natural language – in their material realisation)

6. Continuities in Cognitive Space Clark’s recent work argues for two key cognitive continuities (= no “profound” transformation in “the brain’s own basic modes of representation and computation”) Linguistic Competence Decoupling

7. Continuity: Preservation or Violation? • Continuity is violated if a transition in cognitive competence requires a profound transformation in the brain’s own basic modes of representation and computation • How one identifies the brain’s own basic modes of representation and computation, and what would count as a profound transformation in them, is left uncomfortably vague by Clark. This will be important later • For most of what follows I shall concentrate on the coupled-decoupled transition • And I shall begin by considering non-linguistic intelligence

8. Orthodox Continuity • Orthodox cognitive science preserves continuity for (what I shall call) the perception-action-to-perception-plus transition, that is, between (a) environmentally engaged perception-action (coupled case) and (b) environmentally disengaged post-perceptual recall or pseudo-perceptual imagining (decoupled case). • How? The very same inner processing strategies as are deployed in the coupled case may be deployed in the decoupled case, because there already exist, from the coupled case, appropriate inner surrogates for the now missing external elements

9. Continuity Continued? • According to EM, during real-time coupled intelligence, certain internal mechanisms become directly causally locked onto the contributing external elements. That’s what supports the out-sourcing of complexity. • In decoupled intelligence, however, there are no external elements present onto which the mechanisms concerned could be locked • So what does EM say about the decoupled cases? • The very same kind of inner processing strategies may still be deployed, if there are in place appropriate inner surrogates for just those missing external elements. • It’s at least plausible that where EM is in force, continuity may be preserved for the perception-action-to-perception-plus transition (although note that there might be a tricky question about just where those inner surrogates come from in development) • But now… what about the case of linguistic cognition?

10. A Test Case: Decoupled Maths • Clark (Being There): “experience with drawing and using Venn diagrams allows us to train a neural network which subsequently allows us to manipulate imagined Venn diagrams in our heads… there is no reason to suppose that such training results in the installation of a different kind of computational device. It is the same old process of pattern-completion in high-dimensional representational spaces, but applied to the special domain of a specific kind of external representation” • So Clark preserves continuity across the coupled-decoupled transition for linguistic cognition by treating decoupled linguistic intelligence as just another case of post-perceptual recall / pseudo-perceptual imagination • But is this plausible? • NB: the Venn diagram example is (at best) misleading here

11. Surrendering to the Enemy • The idea seems to be (must be?) this: when linguistic intelligence is coupled, all the linguistic environment does is provide marks or signs, so when linguistic intelligence is decoupled, we simply imagine those marks or signs in our heads. No profound inner transformation necessary. • If this is right, then in the case of coupled linguistic intelligence, fancy internal mechanisms of interpretation seem to be required (there’s been no obvious out-sourcing of complexity), so, for all Clark’s EM rhetoric, the inner states and mechanisms remain essentially just as the orthodox cognitive scientist says they are. • If this is EM, then it’s in danger of failing to earn its keep • Conclusion: Clark preserves the coupled-decoupled continuity in the case of linguistic cognition only by giving up on EM

12. Clark Bites Back • Clark’s response is to focus attention on Elman’s dynamical-connectionist studies of linguistic processing which he (Clark) takes (a) to be consistent with coupled-decoupled continuity in the linguistic case, and (b) to support EM with respect to coupled linguistic intelligence. • But while (a) seems right, (b) doesn’t • In the agreed case, Elman’s own statistical analysis of the successful net demonstrated that it had induced several categories of words implicit in the distributional regularities in the input data: e.g., nouns (sub-divided as animates and inanimates) and verbs (sub-divided as requiring a direct object, optionally taking a direct object, intransitive) • If we proceed to reify these higher-order, statistically visible states, they surely count as the kind of complex inner elements which indicate that Clark has indeed, as suspected, preserved the coupled-decoupled continuity in the case of linguistic cognition by giving up on EM

13. On Refusing to Reify • There’s a representational-computational level of description at which we don’t see linguistically structured states, but that observation alone surely can’t carry the day (imagine what a representationally liberal Fodor and Pylyshyn might say; and persistence of representational-computational formats at an implementational level won’t do here) • Clark (2004 response to Wheeler) holds that representation and computation are intimately co-defined, so we might refuse to reify the higher order structures here as representations because those structures are not the objects of computational processes • But this strategy applied generally would write a blank cheque to all kinds of eliminativism • Clark might allow that higher-order notions of representation and computation apply here, but claim that these higher-order structures and processes don’t count as the basic modes of representation and computation • But how do we decide what count as the basic modes?

14. Conclusions • Our main conclusion still stands: Clark preserves the coupled-decoupled continuity in the case of linguistic cognition only by giving up on EM • And there’s a sting in the tale: the non-linguistic-to-linguistic continuity now seems to have been violated. • Having agreed to the reification of the statistically visible states of the Elman network, we’ve plausibly witnessed a profound transformation in the brain’s own basic mode of representation. (NB: there remain some tricky issues here to be resolved) • If this is right, then we still have no idea how an EM psychology of language might go!