Some thoughts on Larry Shapiro’s excellent The Mind Incarnate .
Shapiro identifies two related Cartesian Materialism ghosts. The first is the multiple realizability thesis (MRT); the second is what Shapiro terms the “separability thesis”.
MRT is the generic idea being that the mind is only contingently dependent on the brain, the a priori implication being that a mind can be instantiated in any material. Just because ubiquitous artefactual objects or devices are supposedly multiply realizable (MR), such theorists extrapolate that mind must operate in these terms as well. Shapiro seeks to reign in the creeping promiscuity of the concept of MRT, suggesting that proper discussion of MRT should be subject to empirical considerations as and when they arise. It should be admitted that corkscrews and kites have less constraints on MR than do brains. Shapiro throws down the gauntlet. What exactly is meant by realization? – what criteria can be offered? Just because a kite can be made of paper and another of nylon, does this really qualify as a multiple realization? Can a corkscrew operate as a corkscrew if it were realised in a non-rigid material? What is the relation between structure and function? In contrast with MRT, Shapiro’s mental constraint thesis (MCT) is “the thesis that there are few distinct kinds of brains that can actually produce human-like psychological capacities” (p. 106). Facts about the wiring of the brain and convergence on topographic mapping of sensory information of mammals are nomonological.
The second ghost is actually a pair of twins, closely related but not identical. Both ghosts partake in what Shapiro terms the “separability thesis” (ST). According to ST, from the knowledge of mental properties it is impossible to infer the properties of the body because they can be realized in different kinds of structures. One twin claims that the mind is much like a computer program that can be specified independently of the hardware it runs on – call this the body neutrality ghost. The other twin conceives the brain as a self-contained organ, the body merely an antenna-like device, a receptacle for somatosensory and sensorimotor input providing cognitive computation for the brain, a closed causal system – Shapiro calls this the envatment ghost. Both these ghosts have been the sine qua non of philosophy of mind, generating intuitions that deny that there is an essential relation between human physicality and cognition. Shapiro is optimistic that the traditional mind-body distinction is being corroded in light of the embodied cognition literature.
manwithoutqualities 