Alex and Tobias from their post:
"The ground rule of (Fodorian) modularity is domain specificity: computational systems can only parse and compute units that belong to a proprietary vocabulary that is specific to the system at hand."
"Hence Hale & Reiss' statement that nothing can be parsed by the cognitive system that wasn't present at birth (or that the cognitive system does not already know) appears to be just incorrect. Saying that unknown stimulus can lead to cognitive categories everywhere except in phonology seems a position that is hard to defend."
I think both parties here are invoking Fodor, but with different emphases. Alex and Tobias are cleaving reasonably close to Fodor 1983 while Charles and Mark are continuing some points from Fodor 1980, 1998.
But Fodor is a little more circumspect than Alex and Tobias about intermodular information transfer:
Fodor 1983:46f: "the input systems are modules ... I imagine that within (and, quite possibly, across)[fn13] the traditional modes, there are highly specialized computational mechanisms in the business of generating hypotheses about the distal sources of proximal stimulations. The specialization of these mechanisms consists in constraints either on the range of information they can access in the course of projecting such hypotheses, or in the range of distal properties they can project such hypotheses about, or, most usually, on both."
"[fn13] The "McGurk effect" provides fairly clear evidence for cross-modal linkages in at least one input system for the modularity of which there is independent evidence. McGurk has demonstrated that what are, to all intents and purposes, hallucinatory speech sounds can be induced when the subject is presented with a visual display of a speaker making vocal gestures appropriate to the production of those sounds. The suggestion is that (within, presumably, narrowly defined limits) mechanisms of phonetic analysis can be activated by -- and can apply to -- either acoustic or visual stimuli. It is of central importance to realize that the McGurk effect -- though cross-modal -- is itself domain specific -- viz., specific to language. A motion picture of a bouncing ball does not induce bump, bump, bump hallucinations. (I am indebted to Professor Alvin Liberman both for bringing McGurk's results to my attention and for his illuminating comments on their implications.)" [italics in original]
I think this quote deserves a slight qualification, as there is now quite a bit of evidence for multisensory integration in the superior temporal sulcus (e.g. Noesselt et al 2012). As for "bump, bump, bump", silent movies of people speaking don't induce McGurk effects either. The cross-modal effect is broader than Fodor thought too, as non-speech visual oscillations that occur in phase with auditory oscillations do enhance brain responses in auditory cortex (Jenkins et al 2011).
To restate my own view again, to the extent that the proximal is partially veridical with the distal, such computational mechanisms are substantive (both the elements and the relations between elements). The best versions of such computational mechanisms attempt to minimize both substance (the functions operate over a minimum number of variables about distal sources; they provide a compact encoding) and arbitrariness (the "dictionary" is as small as possible; it contains just the smallest fragments that can serve as a basis for the whole function; the encoding is compositional and minimizes discontinuities).
And here's Fodor on the impossibility of inventing concepts:
Fodor 1980:148: "Suppose we have a hypothetical organism for which, at the first stage, the form of logic instantiated is propositional logic. Suppose that at stage 2 the form of logic instantiated is first-order quantificational logic. ... Now we are going to try to get from stage 1 to stage 2 by a process of learning, that is, by a process of hypothesis formation and confirmation. Patently, it can't be done. Why? ... [Because] such a hypothesis can't be formulated with the conceptual apparatus available at stage 1; that is precisely the respect in which propositional logic is weaker than quantificational logic."
Fodor 1980:151: "... there is no such thing as a concept being invented ... It is not a theory of how you acquire concepts, but a theory of how the environment determines which parts of the conceptual mechanism in principle available to you are in fact exploited." [italics in original]
You can select or activate a latent ability on the basis of evidence and criteria (the first order analysis might be much more succinct than the propositional analysis) but you can't build first order logic solely out of the resources of propositional logic. You have to have first order logic already available to you in order for you to choose it.
Fodor JA 1980. On the impossibility of acquiring "more powerful" structures. Fixation of belief and concept acquisition. In M Piattelli-Palmarini (ed.) Language and Learning: The Debate between Jean Piaget and Noam Chomsky. Harvard University Press. 142-162.
Fodor JA 1983. Modularity of Mind. MIT Press.
Fodor JA 1998. Concepts: Where Cognitive Science went Wrong. Oxford University Press.
Jenkins J, Rhone AE, Idsardi WJ, Simon JZ, Poeppel D 2011. The Elicitation of Audiovisual Steady-State Responses: Multi-Sensory Signal Congruity and Phase Effects. Brain Topography, 24(2), 134–148.
Noesselt T, Bergmann D, Heinze H-J, Münte T, Spence C 2012. Coding of multisensory temporal patterns in human superior temporal sulcus. Frontiers in Integrative Neuroscience, 6, 64.