“In Defense of Some `Cartesian` Assumptions Concerning the Brain and Its Operation”. Rick Grush (2003)

DRAFT (to be proofread)

Important point: to look for an alternative model to the computational theory (in other “machines”)

The author argues against two main theses related to the embodied cognition conception (and to other close approaches in cognitive science), claimed by who Crush called “the radicals” (Haugeland, Brooks, Clark, Van Gelder and Thelen, among others):

-The mind is not in the brain: cognition involves the interaction between brain, body and environment in such a way that the brain cannot be separate from this system [I will dub it “thesis BBE”].

-Cognition does not require representation [I will call it “thesis NR”].

The `Cartesian` assumptions will be the two opposite ideas: the mind have and manipulate representations [perhaps the claim here is too strong], and the mind is autonomous. But at the same time the author rejects standard cognitive science, in particular symbolic computationalism, so REPRESENTATION WITHOUR SYMBOLS (or without symbolic computation). But, what is the meaning of `representation` in this context? The answer is provided by the emulation theory: roughly speaking, the brain have two parallel functions, one as a controller and other as a emulator, the representations are embodied in the emulator

“The world is not enough” (86) (Cf. Brook)

Key argument against the view of representation in Gelder: p. 65

Brook: mechanisms interacts directly with the world, they don’ t need a kind of “in-between” construction (that is, representations) (see 68).

I am specially concern in the role of neuroscience in the enquiry on mind, and a significant feature of this article is the attention drawn [participio pasado comprobar] to real biological systems, particularly to the brain, along with some suggestions content about neuroscience (see 64).

The emulation framework is a kind of information processing strategy that in fact is implement in the nervous system: “The main idea is that musculoskeletal emulator can process efferent copies and provide predictions of what the peripheral signal will be before the real peripheral signal is available” (76). Evidence Gush mentions to support his claim is that certain movement errors have been explained  (Wolpert, Ghahramani and Jordan, 1995)  “on the assumption that during the initial phases of a movement, before proprioceptive feedback is available, the motor centers exploit feedback from an internal model of the musculo-skeletal system, while as time progresses, feedback from the periphery is incorporated into the estimate” (77).  This internal model would be the emulator [related also to the simulation theory]

Another empirical evidence: Visual imagery (78) and visual perception (see Kosslyn)

PROBLEM: difference between on-line and off-line emulator operation  

PROBLEM: How the argument about emulator and representation match with the argument about components

QUESTION: the argument based on the plug criterion and the pilot example (80) is enough to conclude that “the brain is a notionally self-contained   locus of representational efficacy, not something that is essencially dependent upon the environment with which it is interacting…” (81). How the fact that the brain contains both the controller and the emulator is crucial for the brain to be a self-contained system?

The key point, I think, is that the emulator can operates without interaction with the real world

The argument rests on the emulation framework (74), in which is based the emulation theory of representation “according to which the brain constructs inner dynamical models, or emulators, of the body and environment which are used in parallel with the body and environment to enhance motor control and perception and to provide faster feedback during motor processes, and can be run off-line to produce imagery and evaluate sensoriomotor conterfactuals” (53).

The author agree whith the radicals on many points (see 55, 87-88):

-The emphasis in sensoriomotor control.

The Watt governor and the Timothy van Gelder interpretation

The Watt governor is a feedback controller. Many feedback controller work because they form a dynamical system. Crush calls the strong coupling thesis the claim that “brain and body/environment are coupled in the way that a controller and plant are coupled in a feedback control scheme” (59). (closed-loop control and mutual interaction).  This lead to an “radical” idea called by the author “the strong coupling thesis” (59), according to which “the brain and body/environment are coupled in the way that a controller and plant are coupled in a feedback control scheme –they are in a state of mutual causal influence, and appropriate behaviors are an outcome of this interaction” (59).  See “the dependence thesis”.

ONE PROBLEM: How identify and individualize (analyse) components? (67)

-Functions: Interface/component argument (Haugeland)

-Activities (Brook)

-Plug criterion (Gursh)

I find very interesting the idea that the brain could employ different strategies for different purposes, and from this perspective different models of the mind/body system may be right or reveals some aspect of its organization. In this sense the goal of the author would be to add the emulation framework to a set of tools consisting of theories such as classical symbol manipulation, connectionism, and dynamical system theory (88).

Finally, could be interesting to note the rhetorical or argumentative strategy followed by the author, namely, to accept some premises from those he is going to criticize leading to different conclusions:  “…Showing how even on their own terms, there is a powerful model of sensorionotor function that underwrites the Cartesian assumptions” (55). Another example is that  the concept of representation satisfices the conditions established by Haugeland in order to be a representation (see 83-84).