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variety. There are other programs which have randomizing devices that will give some |
variety but not out of any deep desire. Such programs could be reset with the internal |
random number generator as it was the first time, and once again, the same game would |
ensue. Then there are other programs which do learn from their mistakes, and change |
their strategy depending on the outcome of a game. Such programs would not play the |
same game twice in a row. Of course, you could also turn the clock back by wiping out |
all the changes in the memory which represent learning, just as you could reset the |
random number generator, but that hardly seems like a friendly thing to do. Besides, is |
there any reason to suspect that you would be able to change any of your own past |
decisions if every last detail-and that includes your brain, of course-were reset to the way |
it was the first time around? |
But let us return to the question of whether "choice" is an applicable term here. If |
programs are just "fancy marbles rolling down fancy hills", do they make choices, or not? |
Of course the answer must be a subjective one, but I would say that pretty much the same |
considerations apply here as to the marble. However, I would have to add that the appeal |
of using the word "choice", even if it is only a convenient and evocative shorthand, |
becomes quite strong. The fact that a chess program looks ahead down the various |
possible bifurcating paths, quite unlike a rolling marble, makes it seem much more like |
an animate being than a square-root-of-2 program. However, there is still no deep self- |
awareness here-and no sense of free will. |
Now let us go on to imagine a robot which has a repertoire of symbols. This robot |
is placed in a T-maze. However, instead of going for the reward, it is preprogrammed to |
go left whenever the next digit of the square root: of 2 is even, and to go right whenever it |
is odd. Now this robot is capable of modeling the situation in its symbols, so it can watch |
itself making choices. Each time the T is approached, if you were to address to the robot |
the question, "Do you know which way you're going to turn this time?" it would have to |
answer, "No". Then in order to progress, it would activate its "decider" subroutine, which |
calculates the next digit of the square root of 2, and the decision is taken. However, the |
internal mechanism of the decider is unknown to the robot-it is represented in the robot's |
symbols merely as a black box which puts out "left"'s and "right'"s by some mysterious |
and seemingly random rule. Unless the robot's symbols are capable of picking up the |
hidden heartbeat of the square root of 2, beating in the L's and R's, it will stay baffled by |
the "choices" which it is making. Now does this robot make choices? Put yourself in that |
position. If you were trapped inside a marble rolling down a hill and were powerless to |
affect its path, yet could observe it with all your human intellect, would you feel that the |
marble's path involved choices? Of course not. Unless your mind is affecting the |
outcome, it makes no difference that the symbols are present. |
So now we make a modification in our robot: we allow its symbols-including its self- |
symbol-to affect the decision that is taken. Now here is an example of a program running |
fully under physical law, which seems to get much more deeply at the essence of choice |
than the previous examples did. When the robot's own chunked concept of itself enters |
the scene, we begin to identify with the robot, for it sounds like the kind of thing we do. It |
is no longer like the calculation of the square root of 2, where no symbols seem to be |
monitoring the decisions taken. To be sure, if we were to look at the robot's program on a |
very local level, it would look quite like the square-root program. Step after step is |
executed, and in the end "left" or "right" is the output. But on a high level we can see the |
fact that symbols are being used to model the situation and to affect the decision. That |
radically affects our way of thinking about the program. At this stage, meaning has |
entered this picture-the same kind of meaning as we manipulate with our own minds. |
A Godel Vortex Where All Levels Cross |
Now if some outside agent suggests 'L' as the next choice to the robot, the suggestion |
will be picked up and channeled into the swirling mass of interacting symbols. There, it |
will be sucked inexorably into interaction with the self-symbol, like a rowboat being |
pulled into a whirlpool. That is the vortex of the system, where all levels cross. Here, the |
'L' encounters a Tangled Hierarchy of symbols and is passed up and down the levels. The |
self-symbol is incapable of monitoring all its internal processes, and so when the actual |
decision emerges-'L' or 'R' or something outside the system-the system will not be able to |
say where it came from. Unlike a standard chess program, which does not monitor itself |
and consequently has no ideas about where its moves come from, this program does |
monitor itself and does have ideas about its ideas-but it cannot monitor its own processes |
in complete detail, and therefore has a sort of intuitive sense of its workings, without full |
understanding. From this balance between self-knowledge and self-ignorance comes the |
feeling of free will. |
Think, for instance, of a writer who is trying to convey certain ideas which to him |
are contained in mental images. He isn't quite sure how those images fit together in his |
mind, and he experiments around, expressing things first one way and then another, and |
finally settles on some version. But does he know where it all came from? Only in a |
vague sense. Much of the source, like an iceberg, is deep underwater, unseen-and he |
knows that. Or think of a music composition program, something we discussed earlier, |
asking when we would feel comfortable in calling it the composer rather than the tool of |
a human composer. Probably we would feel comfortable when self-knowledge in terms |
of symbols exists inside the program, and when the program has this delicate balance |
between self-knowledge and self-ignorance. It is irrelevant whether the system is running |
deterministically; what makes us call it a "choice maker" is whether we can identify with |
a high-level description of the process which takes place when the |
program runs. On a low (machine language) level, the program looks like any other |
program; on a high (chunked) level, qualities such as "will", "intuition", "creativity", and |
"consciousness" can emerge. |
The important idea is that this "vortex" of self is responsible for the tangledness, |
for the Godelian-ness, of the mental processes. People have said to me on occasion, "This |
stuff with self-reference and so on is very amusing and enjoyable, but do you really think |
there is anything serious to it?" I certainly do. I think it will eventually turn out to be at |
the core of AI, and the focus of all attempts to understand how human minds work. And |
that is why Godel is so deeply woven into the fabric of my book. |
An Escher Vortex Where All Levels Cross |
A strikingly beautiful, and yet at the same time disturbingly grotesque, illustration of the |
cyclonic "eye" of a Tangled Hierarchy is given to us by Escher in his Print Gallery (Fig. |
142) . What we see is a picture gallery where a young man is standing, looking at a |
picture of a ship in the harbor of a small town, perhaps a Maltese town, to guess from the |
architecture, with its little turrets, occasional cupolas, and flat stone roofs, upon one of |