GREY WALTER - The Cybernetic Brain - page 48

Figure 3.7. The brain of the tortoise. Source: walter 1953, 289, fig. 22.
around when it picked up a light. 12 This interpretation found some empirical
support. As Walter noted (1953, 109), “There was the curious coincidence
between the frequency of the alpha rhythms and the period of visual persis-
tence. This can be shown by trying how many words can be read in ten sec-
onds. It will be found that the number is about one hundred—that is, ten
per second, the average frequency of the alpha rhythms” (Walter 1953, 109).
He also mentioned the visual illusion of movement when one of a pair of
lights is turned off shortly after the other. Such data were at least consistent
with the idea of a brain that lives not quite in the instantaneous present, but
instead scans its environment ten times a second to keep track of what is
going on. 13
From a scientific perspective, then, the tortoise was a model of the brain
which illuminated the go of adaptation to an unknown environment—how it
might be done—while triangulating between knowledge of the brain emanat-
ing from EEG research and ideas about scanning.
tortoise ontology
We can leave the technicalities of the tortoise for a while and think about
ontology. I do not want to read too much into the tortoise—later machines
and systems, especially Ashby's homeostat and its descendants, are more
ontologically interesting—but several points are worth making. First, the
assertion that the tortoise, manifestly a machine, had a “brain,” and that the
functioning of its machine brain somehow shed light on the functioning of
the human brain, challenged the modern distinction between the human and
the nonhuman, between people and animals, machines and things. This is