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

classical models they inspire are doomed to fail, as are attempts to produce artificial
intelligence in such machines (Churchland & Sejnowski, 1992; Dreyfus, 1972, 1992;
Searle, 1980).
In concert with rejecting the digital computer metaphor, connectionist and
embodied cognitive scientists turn to qualitatively different notions in an attempt
to distinguish their approaches from the classical theories that preceded them.
However, their attempt to define the mark of the classical, and to show how this
mark does not apply to their theories, is not always successful.
For example, it was argued in the previous section that when scholars abandoned
the notion of centralized control, they were in fact reacting against a concept
that was not a necessary condition of classical theory, but was instead an engineering
convenience. Furthermore, mechanisms of control in connectionist and embodied
theories were shown not to be radically different from those of classical models.
The current section provides another such example.
One of the defining characteristics of classical theory is serial processing, the
notion that only one operation can be executed at a time. Opponents of classical
cognitive science have argued that this means classical models are simply too
slow to be executed by the sluggish hardware that makes up the brain (Feldman &
Ballard, 1982). They suggest that what is instead required is parallel processing,
in which many operations are carried out simultaneously. Below it is argued that
characterizing digital computers or classical theories as being serial in nature is not
completely accurate. Furthermore, characterizing alternative schools of thought in
cognitive science as champions of parallel processing is also problematic. In short,
the difference between serial and parallel processing may not provide a clear distinction
between different approaches to cognitive science.
It cannot be denied that serial processing has played an important role in the
history of modern computing devices. Turing’s (1936) original account of computation
was purely serial: a Turing machine processed only a single symbol at a time,
and did so by only executing a single operation at a time. However, the purpose of
Turing’s proposal was to provide an uncontroversial notion of “definite method”;
serial processing made Turing’s notion of computation easy to understand, but was
not a necessary characteristic.
A decade later, the pioneering stored program computer EDVAC was also a
serial device in two different ways (Ceruzzi, 1997; von Neumann, 1993). First, it only
executed one command at a time. Second, even though it used 44 bits to represent a
number as a “word,” it processed these words serially, operating on them one bit at
a time. Again, though, this design was motivated by a desire for simplicity—in this
case, simplicity of engineering. “The device should be as simple as possible, that is,
contain as few elements as possible. This can be achieved by never performing two
Marks of the Classical? 335