The Analog/Digital Distinction
in the Philosophy of Mind
Researcher: Ellie Epp
- Date Complete: 1993/04
- Degree Awarded: M.A.
- Research Supervisors: Philip Hanson and A.D. Irvine
Abstract
The computer metaphor of mind has been developed in an era when the serial
digital computer is in ascendancy, and those classical cognitivists who
support a notion of strong equivalence between mental and computational
processes have had a von Neumann architecture in mind. Analog computers
have offered an alternative picture of computation, and von Neumann's The
Computer and the Brain, published in 1958, brought this sense of
an alternative into the philosophy of mind by suggesting that human cognition
is a function of processes, some of which are analog, not digital.
I have examined the analog/digital distinction in the light of this suggestion,
looking first at the engineering community's uses of the contrast, and
then at several sorts of philosophic construal of the terms. I conclude
that, seen at the hardware level, there is no philosophically important
difference between analog and digital computation, and that the contrast
has its primary use in a dispute among language communities -- those who
offer explanations in formal/linguistic terms, and those who offer explanations
in physical/mathematical terms.
Analog or connectionist systems are not easily interpreted as symbol-using
systems, because they lack disjoint, finitely differentiated elements.
Their intransigence in code terms, combined as it is with computational
efficacy, suggests that we do not have to think of computation in terms
of symbols. But those who offer a logical systems explanation have tended
to think of the brain as code-using as well as code-describable. Those
who say that some if not all intelligent processes do not use code have
tended to avoid a logical systems explanation in favour of explanation
in dynamical systems terms. I argue that this separation of vocabularies
is not necessary if we do not assume symbol-describable cognition is symbol-using
cognition, and that any sort of formal modeling, whether logical or mathematical,
implies symbol-describability at some level. The larger importance of connectionist
processing does not lie in its resistance to description in symbol terms,
but in the suggestions it offers about how cognitive states may have intrinsic
content.
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