Michael ArbibMichael 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.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).