Mind, Body, World- Foundations of Cognitive Science, 2013a

to make. For instance, in Chapter 8 we consider in detail his theory of seeing and
visualizing (Pylyshyn, 2003c, 2007); it is argued that this is a hybrid theory, because
it incorporates elements from all three schools of thought in cognitive science.
However, one of the key elements of Pylyshyn’s theory is that vision is quite
distinct from cognition; he has made an extended argument for this position. When
he appealed to connectionist networks or embodied access to the world, he did so
in his account of visual, and not cognitive, processes. His view has been that such
processes can only be involved in vision, because they do not appeal to the cognitive
vocabulary and therefore cannot be viewed as cognitive processes. In short, the
cognitive vocabulary is viewed by Pylyshyn as a mark of the classical.
Is the cognitive vocabulary a mark of the classical? It could be—provided that
the semantic level of explanation captures regularities that cannot be expressed at
either the physical or symbolic levels. Pylyshyn (1984) argued that this is indeed the
case, and that the three different levels are independent:
The reason we need to postulate representational content for functional states is
to explain the existence of certain distinctions, constraints, and regularities in the
behavior of at least human cognitive systems, which, in turn, appear to be expressible
only in terms of the semantic content of the functional states of these systems.
Chief among the constraints is some principle of rationality. (Pylyshyn, 1984, p. 38)
However, it is not at all clear that in the practice of classical cognitive science—particularly
the development of computer simulation models—the cognitive level is distinct
from the symbolic level. Instead, classical researchers adhere to what is known
as the formalist’s motto (Haugeland, 1985). That is, the semantic regularities of a
classical model emerge from the truth-preserving, but syntactic, regularities at the
symbolic level.
If the formal (syntactical) rules specify the relevant texts and if the (semantic)
interpretation must make sense of all those texts, then simply playing by the rules is
itself a surefire way to make sense. Obey the formal rules of arithmetic, for instance,
and your answers are sure to be true. (Haugeland, 1985, p. 106)
If this relation holds between syntax and semantics, then the cognitive vocabulary is
not capturing regularities that cannot be captured at the symbolic level.
The formalist’s motto is a consequence of the physical symbol system hypothesis
(Newell, 1980; Newell & Simon, 1976) that permitted classical cognitive science to
replace Cartesian dualism with materialism. Fodor and Pylyshyn (1988, p. 13) adopt
the physical symbol system hypothesis, and tacitly accept the formalist’s motto:
“Because Classical mental representations have combinatorial structure, it is possible
for Classical mental operations to apply to them by reference to their form.”
Note that in this quote, operations are concerned with formal and not semantic properties;
semantics is preserved provided that there is a special relationship between
354 Chapter 7