Minds and Machines

Chapter 13: Minds and Machines

advent of computers: on the other hand computers doing intelligent things previously reserved for humans

even such psychological functions as we share with the animals -- the "passions" -- are mechanical
but not the higher, distinctively human, intellectual functions -- reason, or intelligence

Suppose that there be a machine, the structure of which produces thinking, feeling, and perceiving; imagine this machine enlarged but preserving the same proportions, so that you could enter it as if it were a mill. This being supposed, you might visit its inside; but what would you observe there? Nothing but parts which push and move each other, and never anything that could explain perception. This explanation must therefore be sought in the simple substance, not in the composite, that is, in the machine (Leibniz, Monadology: 17).

Boolean algebra -- using just 1s & 0s for representation and inference -- developed by Boole (1833)
1930s Claude Shannon developed modern theory of information based on Boolean algebra. Each on/off (1/0) was a unit of information he called a "binary digit" or "bit"
Turing described how to build "universal" machines which

being programmable: could prove anything strictly provable
being expandable: would be capable of computations of unlimited complexity
modern digital computers are realizations of Turing's theoretical devices & limited only by their storage capacities

Computational theory of mind: "the brain is a digital computer and the conscious mind is a computer program" (Searle 1997: 9) [note this is not Searle's own view: the context is critical of this view]

brains have many neurons (brain-cells) richly interconnected (by dendrites) interactions across synapses (Fig. 13.2: 186) acting in parallel
similarly connection machines have many simple processors richly interconnected (by wires) acting in parallel -- hence they are called "artificial neural networks" (ANNs) or "neural nets"
representations in these networks is distributed and "subsymbolic"
these networks are not programmed but "trained"

Underlying idea: "mind can be created only by interacting in real time with a real environment" (Blackmore 189)
Intelligence emerges in the interaction of machine and environment.

Rodney Brooks -- roboticist extraordinaire: puts embodied cognition into practice

his robots don't build internal maps or encode descriptions of their worlds (the GOFAI way)
his robots "let the world itself serve as its own model" (Brooks 1991: 396)
"Is is only the observer of the Creature who imputes a central representation or central control. The Creature itself has none; it is a collection of competing behaviors."

"I propose to consider the question 'Can machines think?'" (Turing, 1950)
Proposed an experimental test for AI (a version of Descartes' language test) based on "the imitation game"

"in about fifty years' time it will be possible to program computers ... to play the imitation game so well that an average interrogator will not have more than a 70 percent chance of making the right identification after five minutes of questioning" [down in flames!]
"at the end of the century the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted" [gloriously fulfilled in practice]