Gödel, Escher, Bach: An Eternal Golden Braid (130 page)

Consciousness as an Intrinsically High-Level Phenomenon

Looked at this way, Gödel’s proof suggests-though by no means does it prove!-that there could be some high-level way of viewing the mind/brain, involving concepts which do not appear on lower levels, and that this level might have explanatory power that does not exist-not even in principle-on lower levels. It would mean that some facts could be explained on the high level quite easily, but not on lower levels at all. No matter how long and cumbersome a low-level statement were made, it would not explain the phenomena in question. It is the analogue to the fact that, if you make derivation after derivation in
TNT
, no matter how long and cumbersome you make them, you will never come up with one for
G
-despite the fact that on a higher level, you can see that G is true.

What might such high-level concepts be? It has been proposed for eons, by various holistically or "soulistically" inclined scientists and humanists, that
consciousness
is a phenomenon that escapes explanation in terms of brain-components; so here is a candidate, at least. There is also the ever-puzzling notion of
free will
. So perhaps these qualities could be "emergent" in the sense of requiring explanations which cannot be furnished by the physiology alone. But it is important to realize that if we are being guided by Gödel’s proof in making such bold hypotheses, we must carry the analogy through thoroughly. In particular, it is vital to recall tnat is s nontheoremhood does have an explanation-it is not a total mystery! The explanation- hinges on understanding not just one level at a time, but the way in which one level mirrors its metalevel, and the consequences of this mirroring. If our analogy is to hold, then,

"emergent" phenomena would become explicable in terms of a relationship between.

different levels in mental systems.,

Strange Loops as the Crux of Consciousness

My belief is that the explanations of "emergent" phenomena in our brains-for instance, ideas, hopes, images, analogies, and finally consciousness and free will-are based on a kind of Strange Loop, an interaction between levels in which the top level reaches back down towards the bottom level and influences it, while at the same time being itself determined by the bottom level. In other words, a self-reinforcing "resonance" between different levels-quite like the Henkin sentence which, by merely asserting its own provability, actually becomes provable. The self comes into being at the moment it has the power to reflect itself.

This should not be taken as an antireductionist position. It just implies that a reductionistic explanation of a mind,
in order to be comprehensible
, must bring in "soft"

concepts such as levels, mappings, and meanings. In principle, I have no doubt that a totally reductionistic but incomprehensible explanation of the brain exists; the problem is how to translate it into a language we ourselves can fathom. Surely we don't want a description in terms of positions and momenta of particles; we want a description which relates neural activity to "signals" (intermediate-level phenomena)-and which relates signals, in turn, to "symbols" and "subsystems", including the presumed-to-exist "selfsymbol". This act of translation from low-level physical hardware to high-level psychological software is analogous to the translation of number-theoretical statements into metamathematical statements. Recall that the level-crossing which takes place at this exact translation point is what creates Godel's incompleteness and the self-proving character of Henkin's sentence. I postulate that a similar level-crossing is what creates our nearly unanalyzable feelings of self.

In order to deal with the full richness of the brain/mind system, we will have to be able to slip between levels comfortably. Moreover, we will have to admit various types of

"causality": ways in which an event at one level of description can "cause" events at other levels to happen. Sometimes event A will be said to "cause" event B simply for the reason that the one is a translation, on another level of description, of the other.

Sometimes "cause" will have its usual meaning: physical causality. Both types of causality-and perhaps some more-will have to be admitted in any explanation of mind, for we will have to admit causes that propagate both upwards
and
downwards in the Tangled Hierarchy of mentality, just as in the Central Dogmap.

At the crux, then, of our understanding ourselves will come an understanding of the Tangled Hierarchy of levels inside our minds. My position is rather similar to the viewpoint put forth by the neuroscientist Roger Sperry in his excellent article "Mind, Brain, and Humanist Values", from which I quote a little here: In my own hypothetical brain model, conscious awareness does get representation as a very real causal agent and rates an important place in the causal sequence and chain of control in brain events, in which it appears as an active, operational force.... To put it very simply, it comes down to the issue of who pushes whom around in the population of causal forces that occupy the cranium. It is a matter, in other words, of straightening out the peck-order hierarchy among intracranial control agents. There exists within the cranium a whole world of diverse causal forces; what is more, there are forces within forces within forces, as in no other cubic half-foot of universe that we know. ... To make a long story short, if one keeps climbing upward in the chain of command within the brain, one finds at the very top those over-all organizational forces and dynamic properties of the large patterns of cerebral excitation that are correlated with mental states or psychic activity.... Near the apex of this command system in the brain ... we find ideas. Man over the chimpanzee has ideas and ideals. In the brain model proposed here, the causal potency of an idea, or an ideal, becomes just as real as that of a molecule, a cell, or a nerve impulse. Ideas cause ideas and help evolve new ideas. They interact with each other and with other mental forces in the same brain, in neighboring brains, and, thanks to global communication, in far distant, foreign brains. And they also interact with the external surroundings to produce in toto a burstwise advance in evolution that is far beyond anything to hit the evolutionary scene yet, including the emergence of the living cell.'

There is a famous breach between two languages of discourse: the subjective language and the objective language. For instance, the "subjective" sensation of redness, and the "objective" wavelength of red light. To many people, these seem to be forever irreconcilable. I don't think so. No more than the two views of Escher's
Drawing Hands
are irreconcilable from "in the system", where the hands draw each other, and from outside, where Escher draws it all. The subjective feeling of redness comes from the vortex of self-perception in the brain; the objective wavelength is how you see things when you step back, outside of the system. Though no one of us will ever be able to step back far enough to see the "big picture", we shouldn't forget that it exists. We should remember that physical law is what makes it all happen-way, way down in neural nooks and crannies which are too remote for us to reach with our high-level introspective probes.

The Self-Symbol and Free Will

In Chapter XI I, it was suggested that what we call free will is a result of the interaction between the self-symbol (or subsystem), and the other symbols in the brain. If we take the idea that symbols are the high-level entities to

which meanings should be attached, then we can' make a stab at explaining the relationship between symbols, the self-symbol, and free will.

One way to gain some perspective on the free-will question is to replace it by what I believe is an equivalent question, but one which involves less loaded terms.

Instead of asking, "Does system X have free will?" we ask, "Does system X make choices?" By carefully groping for what we really mean when we choose to describe a system-mechanical or biological-as being capable of making "choices", I think we can shed much light on free will it will be helpful to go over a few different systems which, under various circumstances, we might feel tempted to describe as "making choices".

From these examples we can gain some perspective on what we really mean by the phrase.

Let us take the following systems as paradigms: a marble rolling down a bumpy hill; a pocket calculator finding successive digits in the decimal expansion of the square root of 2; a sophisticated program which plays a mean game of chess; a robot in a T-maze (a maze with but a single fork, on one side of which there is a reward); and a human being confronting a complex dilemma.

First, what about that marble rolling down a hill? Does it make choices? I think we would unanimously say that it doesn't, even though none of us could predict its path for even a very short distance. We feel that it couldn't have gone any other way than it did, and that it was just being shoved along by the relentless laws of nature. In our chunked mental physics, of course, we can visualize many different "possible" pathways for the marble, and we see it following only one of them in the real world. On some level of our minds, therefore, we can't help feeling the marble has "chosen" a single pathway out of those myriad mental ones; but on some other level of our minds, we have an instinctive understanding that the mental physics is only an aid in our internal modeling of the world, and that the mechanisms which make the real physical sequences of events happen do not require nature to go through an analogous process of first manufacturing variants in some hypothetical universe (the "brain of God") and then choosing between them. So we shall not bestow the designation "choice" upon this process-although we recognize that it is often pragmatically useful to use the word in cases like this, because of its evocative power.

Now what about the calculator programmed to find the digits of the square root of 2? What about the chess program? Here, we might say that we are just dealing with

"fancy marbles", rolling down "fancy hills". In fact, the arguments for no choice-making here are, if anything, stronger than in the case of a marble. For if you attempt to repeat the marble experiment, you will undoubtedly witness a totally different pathway being traced down the hill, whereas if you rerun the square-root-of-2 program, you will get the same results time after time. The marble seems to "choose" a different path each time, no matter how accurately you try to reproduce the conditions of its original descent, whereas the program runs down precisely the same channels each time.

Now in the case of fancy chess programs, there are various possibilities.

If you play a game against certain programs, and then start a second game with the same moves as you made the first time, these programs will just move exactly as they did before, without any appearance of having learned anything or having any desire for 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.