The Parable of the Adding Machine
I suppose we science fiction writers are to blame for the modern phenomenon of people who think computers think, that adding machines add, and so on. I have never seen a version of Pinocchio done where the puppet was never brought to life by the fairy, but Geppetto merely was convinced by BF Skinner or Karl Marx or Lucretius that the puppet was alive 0n the grounds that it moved when it strings were pulled.
Like this crazy version of Geppetto, there are some men these days who are convinced that since computers move numbers around, therefore they think, therefore humans (who think) are nothing but computers.
But even if the logic were sound, the premise is wrong. A computer does not literally move numbers around. That expression is merely a metaphor.
What it the computer is literally doing is moving around (in an adding machine) gears (and in an electronic calculator) electrons. The numbers are symbols whose meaning we assign to them.
Suppose I were to make a simple adding machine that only performed one operation. If I write a straight line on one face or cog of a wheel, and do this again for a second wheel and for a third, and I moreover cunningly place a fourth wheel next to them connected by linkages so that turning the first three wheels to the straight line pulls the fourth wheel so that the face or cog showing a symbol that looks like a sideways trident is showing, why, then, I have a “calculator” that can perform one operation: 1+1+1=3.
But there is no number “one” anywhere in the wheels. That number is something I contemplate with my mind and which I (and everyone else who decides to use Arabic numerals) assign or attribute to the straight line. Again, the numeral III is one that I (and everyone else) assign to the trident-looking squiggle.
Please note that there is no addition sign nor equals sign in my example. The man using the simple adding machine assigns those things to the positions of the wheels, using ‘position’ as a symbol or sign the same way the squiggles are symbols or signs.
Now, again, suppose I take a second set of wheels, cunningly interconnected to turn another face or cog when the faces of the first set is moved into certain positions, and so perform a second operation; suppose again that I make a third set of wheels, or as many wheels as there are entries in a multiplication table. Provided my wheels do not slip any gears, I have an adding machine which can help me calculate.
If I am particularly ambitious, I can add hooks or pins or punch cards to the faces of my machine of many wheels, and have the wheels act like the tumblers of a lock, so that certain combinations of wheel turnings will set in motion other appliances connected to the machine, such as alarm clocks, photographs, typewriters, telegraphs, telephones, gramophones, whistles and bells and even the post box. But no matter how elaborate, the thing is still a clockwork. For reasons of saving space, I can do that exact same thing with a cellphone, using electrons rather than wheels and gears: but the nature of the machine is the same.
Now before we wax poetical about how machines think and it is only a matter of a technical tactic to get them to have free will, let us contemplate that a computer is something more complex but otherwise no different than my simple calculation machine of four wheels. Let us not pretending the four wheels understand the abstractions we call numbers, or know their values, or add the values together to deduce the answer.
Nothing like that is going on. Having a dozen four-wheeled machines, or a million, or a googleplex will not change the nature of the process, which is a mechanical motion unrelated to thinking in any way.