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18. Thought / B. Mechanics of Thought / 6. Artificial Thought / b. Turing Machines

[theoretical machine that implements thinking]

5 ideas
The Turing Machine is the best idea yet about how the mind works [Fodor on Turing]
     Full Idea: Alan Turing had (in his theory of the 'Turing Machine') what I suppose is the best thought about how the mind works that anyone has had so far.
     From: comment on Alan Turing (Computing Machinery and Intelligence [1950]) by Jerry A. Fodor - Jerry A. Fodor on himself p.296
     A reaction: I am not convinced, because I don't think rationality is possible without consciousness. The brain may bypass the representations used by a computer.
Turing showed that logical rules can be specified computationally and mechanically [Turing, by Rey]
     Full Idea: Turing showed that any formal process can be specified computationally, and captured by a Turing Machine. Hence logical rules (and arithmetic) could be obeyed not by someone representing and following them, but by causal organisation of the brain.
     From: report of Alan Turing (works [1935]) by Georges Rey - Contemporary Philosophy of Mind 8.2
     A reaction: It is questionable whether logic is an entirely formal process, if it involves truth. You would need an entirely formal notion of truth for that. But a brain can do whatever a flow diagram can do.
Computation isn't a natural phenomenon, it is a way of seeing phenomena [Searle]
     Full Idea: Computational states are not discovered within the physics, they are assigned to the physics.
     From: John Searle (The Rediscovery of the Mind [1992], Ch. 9.V)
     A reaction: The key idea in Searle's later thinking, with which I have some sympathy. There always seems to be a sneaky dualism buried deep in Searle's physicalism. Computation is very high-level physics.
Simple machine-functionalism says mind just is a Turing machine [Block]
     Full Idea: In the simplest Turing-machine version of functionalism (Putnam 1967), mental states are identified with the total Turing-machine state, involving a machine table and its inputs and outputs.
     From: Ned Block (Troubles with Functionalism [1978], p. 70)
     A reaction: This obviously invites the question of why mental states would be conscious and phenomenal, given that modern computers are devoid of same, despite being classy Turing machines.
A Turing machine, given a state and input, specifies an output and the next state [Block]
     Full Idea: In a Turing machine, given any state and input, the machine table specifies an output and the next state. …To have full power the tape must be infinite in at least one direction, and be movable in both directions.
     From: Ned Block (Troubles with Functionalism [1978], p. 71)
     A reaction: In retrospect, the proposal that this feeble item should be taken as a model for the glorious complexity and richness of human consciousness doesn't look too plausible.