Michael Arbib
(1940-)
Michael Arbib is a theoretical neuroscientist and computer scientist who studies the brain from a computational perspective.
Cognitive scientists like Arbib see the mind as containing parts that can be analyzed as logical systems much like the parts of digital computers. This is a very powerful metaphor, but
man is not a machine in the Newtonian sense, as the
reductionist behaviorists assumed, and the
mind is not a computer, although like a computer, it is an
information processing system which acquires, creates, stores, and manages the information needed to guide the actions of its body.
Arbib's 1983 Gifford Lectures (published with Mary Hesse as
The Construction of Reality, 1986) considered the question of
free will in the context of whether computers could be designed to have free will.
Arbib argues that quantum
indeterminacy in the brain is only a necessary and not a sufficient condition for free will.
A factual question arises here as to whether quantum indeterminacy in the brain is at the right level to generate probabilities at points at which one would wish to say "choices" are made.
(The Construction of Reality, p.95)
But Arbib then says this is no help for free will. "It is just as difficult to ascribe responsibility to quantum jumps as to a sequence of predetermined states."
This is the
standard argument against free will.
Arbib considers
Daniel Dennett's
two-stage "mechanist" model, as Arbib calls it. "Of all recent writers on this tangled subject," he says, "Dennett perhaps comes nearest to a sympathetic reconstruction of the [libertarian's] case." (p.96)
But he says three things are wrong with Dennett's model (p.97).
- It begs the question of whether determinism or filpping a coin are the alternatives at the point of decision or at any other point.
- The model falls into an infinite regress about how to account for early "decisions" about what considerations to allow into deliberation and how to weigh them.
- Free will is not well simulated by a last-minute flip of the coin, which seems to abrogate rational deliberation.
Arbib does not fully appreciate Dennett's idea that randomness can be limited to the generation of
alternative possibilities. Dennett's problem, as he himself admits, is the
location of the randomness at a place and time (relative to the decision) that does not compromise
responsibility.
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