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

constraints on symbol manipulations and constraints on symbolic content.
To summarize this section: The interdisciplinary nature of cognitive science
arises because cognitive systems require explanations at multiple levels. Two multiple
level approaches are commonly found in the cognitive science literature.
The first is Marr’s (1982) tri-level hypothesis, which requires cognitive systems
to be explained at the implementational, algorithmic, and computational levels.
It is argued above that all three schools of thought in cognitive science adhere to
the tri-level hypothesis. Though at each level there are technical differences to be
found between classical, connectionist, and embodied cognitive science, all three
approaches seem consistent with Marr’s approach. The tri-level hypothesis cannot
be used to distinguish one cognitive science from another.
The second is a tri-level approach that emerges from the physical symbol system
hypothesis. It argues that information processing requires explanation at three
independent levels: the physical, the symbolic, and the semantic (Dennett, 1987;
Newell, 1982; Pylyshyn, 1984). The physical and symbolic levels in this approach
bear a fairly strong relationship to Marr’s (1982) implementational and algorithmic
levels. The semantic level, though, differs from Marr’s computational level in calling
for a cognitive vocabulary that captures regularities by appealing to the contents of
mental representations. This cognitive vocabulary has been proposed as a mark of
the classical that distinguishes classical theories from those proposed by connectionist
and embodied researchers. However, it has been suggested that this view
may not hold, because the formalist’s motto makes the proposal of an independent
cognitive vocabulary difficult to defend.
7.9 From Classical Marks to Hybrid Theories
Vera and Simon’s (1993) analysis of situated action theories defines one extreme
pole of a continuum for relating different approaches in cognitive science. At this
end of the continuum, all theories in cognitive science—including situated action
theories and connectionist theories—are classical or symbolic in nature. “It follows
that there is no need, contrary to what followers of SA seem sometimes to claim, for
cognitive psychology to adopt a whole new language and research agenda, breaking
completely from traditional (symbolic) cognitive theories” (p. 46).
The position defined by Vera and Simon’s (1993) analysis unites classical, connectionist,
and cognitive science under a classical banner. However, it does so
because key terms, such as symbolic, are defined so vaguely that their value becomes
questionable. Critics of their perspective have argued that anything can be viewed as
symbolic given Vera and Simon’s liberal definition of what symbols are (Agre, 1993;
Clancey, 1993).
Marks of the Classical? 355