Jerry Fodor On Mental Architecture - Why Modularity Matters

Why Modularity Matters

Fodor thinks that a (moderately) modular view of the structure of the mind is necessary to explain the strong degree of autonomy from the central system that certain properties of perception demonstrate. He cites the case of experiments that demonstrate the specificity of domain of the mechanisms that act during the analysis of phonetic information. These experiments apparently demonstrate that the mechanisms of phonetic analysis are exclusively sensible to acoustic sequences of speech. But, according to Fodor, what really distinguishes modules from central processes is what he calls informational encapsulation. This is roughly the thesis that modules are much less open and permeable to background knowledge and beliefs on the part of the individual. Fodor uses the persistence of perceptual illusions to illustrate his thesis. Illusions, such as Müller-Lyer tend to persist long after a subject has been exposed to them and has learned that the two lines are, in fact, equal in length. The knowledge that the two lines are equal is cognitively available and constitutes part of his background knowledge, which he can access consciously at any time. Nevertheless, when looking at the rods, one still effectively sees them as uneven and the illusion persists. This suggests to Fodor that basic perceptual modules are partly closed off from the cognitive background knowledge of the subject: modules are informationally encapsulated. The study of perception is of fundamental importance for illustrating the connection between functional architecture and the theory of mental content. The fact that perception exhibits characteristics of autonomy and independence from central processes (and that it is relatively impenetrable to background knowledge) can be posted at the base of a theoretical conception able to mediate between internalist conceptions (hence preserving representational realism) and externalist conceptions (hence allowing for a causal-informational conception) of mental content.

Fodor’s proposal is characterized by the attempt to converge the causal conception with the inferential thesis of perception. His goal is to break the bond between the inferential thesis and the thesis of the dependence of perception on the system of beliefs/desires of individuals. Basing itself on the importance of background knowledge in perceptual processes, the inferential conception has been utilized in favour of the epistemic hypothesis of perception. This hypothesis fits perfectly with the inferential thesis because it explains the derivation of the hypotheses that the perceptual system projects on the proximal stimulus. The result is a notion of the cognitive permeability of perception: seeing is an interpretive act that depends on the background knowledge of the subject. According to Fodor, however, it is possible to adhere to the inferential thesis without having to subscribe to the idea of cognitive permeability. From the fact that perceptual processes are inferential it does not follow that they must have access to the background knowledge of subjects. But, in order for all of this to work, perceptual systems must be "specialized" and "encapsulated." Our best theory of perception, therefore, seems to require a modular organization of the mind.