Part 8 (2/2)

Try this thought experiment (which will work for those of you who drive a car): Imagine that you are driving in the left lane of a highway. Now close your eyes, grab an imagined steering wheel, and make the movements to change lanes to the lane to your right.

Okay, before continuing to read, try it.

Here is what you probably did: You held the steering wheel. You checked that the right lane is clear. a.s.suming the lane was clear, you turned the steering wheel to the right for a brief period. Then you straightened it out again. Job done.

It's a good thing you weren't in a real car, because you just zoomed across all the lanes of the highway and crashed into a tree. While I probably should have mentioned that you shouldn't try this in a real moving car (but then I a.s.sume you have already mastered the rule that you shouldn't drive with your eyes closed), that's not really the key problem here. If you used the procedure I just described-and almost everyone does when doing this thought experiment-you got it wrong. Turning the wheel to the right and then straightening it out causes the car to head in a direction that is diagonal to its original direction. It will cross the lane to the right, as you intended, but it will keep going to the right indefinitely until it zooms off the road. What you needed to do as your car crossed the lane to the right was to then turn the wheel to the left, just as far as you had turned it to the right, and then then straighten it out again. This will cause the car to again head straight in the new lane. straighten it out again. This will cause the car to again head straight in the new lane.

Consider the fact that if you're a regular driver, you've done this maneuver thousands of times. Are you not conscious when you do this? Have you never paid attention to what you are actually doing when you change lanes? a.s.suming that you are not reading this book in a hospital while recovering from a lane-changing accident, you have clearly mastered this skill. Yet you are not conscious of what you did, however many times you've accomplished this task.

When people tell stories of their experiences, they describe them as sequences of situations and decisions. But this is not how we experience a story in the first place. Our original experience is as a sequence of high-level patterns, some of which may have triggered feelings. We remember only a small subset of those patterns, if that. Even if we are reasonably accurate in our recounting of a story, we use our powers of confabulation to fill in missing details and convert the sequence into a coherent tale. We cannot be certain what our original conscious experience was from our recollection of it, yet memory is the only access we have to that experience. The present moment is, well, fleeting, and is quickly turned into a memory, or, more often, not. Even if an experience is turned into a memory, it is stored, as the PRTM indicates, as a high-level pattern composed of other patterns in a huge hierarchy. As I have pointed out several times, almost all of the experiences we have (like any of the times we changed lanes) are immediately forgotten. So ascertaining what const.i.tutes our own conscious experience is actually not attainable.

East Is East and West Is WestBefore brains there was no color or sound in the universe, nor was there any flavor or aroma and probably little sense and no feeling or emotion.-Roger W. Sperry7 Rene Descartes walks into a restaurant and sits down for dinner. The waiter comes over and asks if he'd like an appetizer.”No thank you,” says Descartes, ”I'd just like to order dinner.””Would you like to hear our daily specials?” asks the waiter.”No,” says Descartes, getting impatient.”Would you like a drink before dinner?” the waiter asks.Descartes is insulted, since he's a teetotaler. ”I think not!” he says indignantly, and POOF! he disappears.-A joke as recalled by David Chalmers

There are two ways to view the questions we have been considering-converse Western and Eastern perspectives on the nature of consciousness and of reality. In the Western perspective, we start with a physical world that evolves patterns of information. After a few billion years of evolution, the ent.i.ties in that world have evolved sufficiently to become conscious beings. In the Eastern view, consciousness is the fundamental reality; the physical world only comes into existence through the thoughts of conscious beings. The physical world, in other words, is the thoughts of conscious beings made manifest. These are of course simplifications of complex and diverse philosophies, but they represent the princ.i.p.al polarities in the philosophies of consciousness and its relations.h.i.+p to the physical world.

The East-West divide on the issue of consciousness has also found expression in opposing schools of thought in the field of subatomic physics. In quantum mechanics, particles exist as what are called probability fields. Any measurement carried out on them by a measuring device causes what is called a collapse of the wave function, meaning that the particle suddenly a.s.sumes a particular location. A popular view is that such a measurement const.i.tutes observation by a conscious observer, because otherwise measurement would be a meaningless concept. Thus the particle a.s.sumes a particular location (as well as other properties, such as velocity) only when it is observed. Basically particles figure that if no one is bothering to look at them, they don't need to decide where they are. I call this the Buddhist school of quantum mechanics, because in it particles essentially don't exist until they are observed by a conscious person.

There is another interpretation of quantum mechanics that avoids such anthropomorphic terminology. In this a.n.a.lysis, the field representing a particle is not a probability field, but rather just a function that has different values in different locations. The field, therefore, is fundamentally what the particle is. There are constraints on what the values of the field can be in different locations, because the entire field representing a particle represents only a limited amount of information. That is where the word ”quantum” comes from. The so-called collapse of the wave function, this view holds, is not a collapse at all. The wave function actually never goes away. It is just that a measurement device is also made up of particles with fields, and the interaction of the particle field being measured and the particle fields of the measuring device results in a reading of the particle being in a particular location. The field, however, is still present. This is the Western interpretation of quantum mechanics, although it is interesting to note that the more popular view among physicists worldwide is what I have called the Eastern interpretation.

There was one philosopher whose work spanned this East-West divide. The Austrian British thinker Ludwig Wittgenstein (18891951) studied the philosophy of language and knowledge and contemplated the question of what it is that we can really know. He pondered this subject while a soldier in World War I and took notes for what would be his only book published while he was alive, Tractatus Logico-Philosophicus Tractatus Logico-Philosophicus. The work had an unusual structure, and it was only through the efforts of his former instructor, British mathematician and philosopher Bertrand Russell, that it found a publisher in 1921. It became the bible for a major school of philosophy known as logical positivism, which sought to define the limits of science. The book and the movement surrounding it were influential on Turing and the emergence of the theory of computation and linguistics.

Tractatus Logico-Philosophicus antic.i.p.ates the insight that all knowledge is inherently hierarchical. The book itself is arranged in nested and numbered statements. For example, the first four statements in the book are: antic.i.p.ates the insight that all knowledge is inherently hierarchical. The book itself is arranged in nested and numbered statements. For example, the first four statements in the book are: 1 The world is all that is the case.1.1 The world is the totality of facts, not of things.1.11 The world is determined by the facts, and by their being all the facts.1.12 For the totality of facts determines what is the case, and also whatever is not the case.

Another significant statement in the Tractatus Tractatus-and one that Turing would echo-is this: 4.0031 All philosophy is a critique of language.

Essentially both Tractatus Logico-Philosophicus Tractatus Logico-Philosophicus and the logical positivism movement a.s.sert that physical reality exists separate from our perception of it, but that all we can know of that reality is what we perceive with our senses-which can be heightened through our tools-and the logical inferences we can make from these sensory impressions. Essentially Wittgenstein is attempting to describe the methods and goals of science. The final statement in the book is number 7, ”What we cannot speak about we must pa.s.s over in silence.” The early Wittgenstein, accordingly, considers the discussion of consciousness as circular and tautological and therefore a waste of time. and the logical positivism movement a.s.sert that physical reality exists separate from our perception of it, but that all we can know of that reality is what we perceive with our senses-which can be heightened through our tools-and the logical inferences we can make from these sensory impressions. Essentially Wittgenstein is attempting to describe the methods and goals of science. The final statement in the book is number 7, ”What we cannot speak about we must pa.s.s over in silence.” The early Wittgenstein, accordingly, considers the discussion of consciousness as circular and tautological and therefore a waste of time.

The later Wittgenstein, however, completely rejected this approach and spent all of his philosophical attention talking about matters that he had earlier argued should be pa.s.sed over in silence. His writings on this revised thinking were collected and published in 1953, two years after his death, in a book called Philosophical Investigations Philosophical Investigations. He criticized his earlier ideas in the Tractatus Tractatus, judging them to be circular and void of meaning, and came to the view that what he had advised that we not speak about was in fact all that was worth reflecting on. These writings heavily influenced the existentialists, making Wittgenstein the only figure in modern philosophy to be a major architect of two leading and contradictory schools of thought in philosophy.

What is it that the later Wittgenstein thought was worth thinking and talking about? It was issues such as beauty and love, which he recognized exist imperfectly as ideas in the minds of men. However, he writes that such concepts do exist in a perfect and idealized realm, similar to the perfect ”forms” that Plato wrote about in the Platonic dialogues, another work that illuminated apparently contradictory approaches to the nature of reality.

One thinker whose position I believe is mischaracterized is the French philosopher and mathematician Rene Descartes. His famous ”I think, therefore I am” is generally interpreted to extol rational thought, in the sense that ”I think, that is I can perform logical thought, therefore I am worthwhile.” Descartes is therefore considered the architect of the Western rational perspective.

Reading this statement in the context of his other writings, however, I get a different impression. Descartes was troubled by what is referred to as the ”mind-body problem”: Namely, how does a conscious mind arise from the physical matter of the brain? From this perspective, it seems he was attempting to push rational skepticism to the breaking point, so in my view what his statement really means is, ”I think, that is to say, a subjective experience is occurring, so therefore all we know for sure is that something-call it I I-exists.” He could not be certain that the physical world exists, because all we have are our own individual sense impressions of it, which might be wrong or completely illusory. We do know, however, that the experiencer exists.

My religious upbringing was in a Unitarian church, where we studied all of the world's religions. We would spend six months on, say, Buddhism and would go to Buddhist services, read their books, and have discussion groups with their leaders. Then we would switch to another religion, such as Judaism. The overriding theme was ”many paths to the truth,” along with tolerance and transcendence. This last idea meant that resolving apparent contradictions between traditions does not require deciding that one is right and the other is wrong. The truth can be discovered only by finding an explanation that overrides-transcends-seeming differences, especially for fundamental questions of meaning and purpose.

This is how I resolve the Western-Eastern divide on consciousness and the physical world. In my view, both perspectives have to be true.

On the one hand, it is foolish to deny the physical world. Even if we do live in a simulation, as speculated by Swedish philosopher Nick Bostrom, reality is nonetheless a conceptual level that is real for us. If we accept the existence of the physical world and the evolution that has taken place in it, then we can see that conscious ent.i.ties have evolved from it.

On the other hand, the Eastern perspective-that consciousness is fundamental and represents the only reality that is truly important-is also difficult to deny. Just consider the precious regard we give to conscious persons versus unconscious things. We consider the latter to have no intrinsic value except to the extent that they can influence the subjective experience of conscious persons. Even if we regard consciousness as an emergent property of a complex system, we cannot take the position that it is just another attribute (along with ”digestion” and ”lactation,” to quote John Searle). It represents what is truly important.

The word ”spiritual” is often used to denote the things that are of ultimate significance. Many people don't like to use such terminology from spiritual or religious traditions, because it implies sets of beliefs that they may not subscribe to. But if we strip away the mystical complexities of religious traditions and simply respect ”spiritual” as implying something of profound meaning to humans, then the concept of consciousness fits the bill. It reflects the ultimate spiritual value. Indeed, ”spirit” itself is often used to denote consciousness.

Evolution can then be viewed as a spiritual process in that it creates spiritual beings, that is, ent.i.ties that are conscious. Evolution also moves toward greater complexity, greater knowledge, greater intelligence, greater beauty, greater creativity, and the ability to express more transcendent emotions, such as love. These are all descriptions that people have used for the concept of G.o.d, albeit G.o.d is described as having no limitations in these regards.

People often feel threatened by discussions that imply the possibility that a machine could be conscious, as they view considerations along these lines as a denigration of the spiritual value of conscious persons. But this reaction reflects a misunderstanding of the concept of a machine. Such critics are addressing the issue based on the machines they know today, and as impressive as they are becoming, I agree that contemporary examples of technology are not yet worthy of our respect as conscious beings. My prediction is that they will become indistinguishable from biological humans, whom we do regard as conscious beings, and will therefore share in the spiritual value we ascribe to consciousness. This is not a disparagement of people; rather, it is an elevation of our understanding of (some) future machines. We should probably adopt a different terminology for these ent.i.ties, as they will be a different sort of machine.

Indeed, as we now look inside the brain and decode its mechanisms we discover methods and algorithms that we can not only understand but re-create-”the parts of a mill pus.h.i.+ng on each other,” to paraphrase German mathematician and philosopher Gottfried Wilhelm Leibniz (16461716) when he wrote about the brain. Humans already const.i.tute spiritual machines. Moreover, we will merge with the tools we are creating so closely that the distinction between human and machine will blur until the difference disappears. That process is already well under way, even if most of the machines that extend us are not yet inside our bodies and brains.

Free WillA central aspect of consciousness is the ability to look ahead, the capability we call ”foresight.” It is the ability to plan, and in social terms to outline a scenario of what is likely going to happen, or what might happen, in social interactions that have not yet taken place.... It is a system whereby we improve our chances of doing those things that will represent our own best interests.... I suggest that ”free will” is our apparent ability to choose and act upon whichever of those seem most useful or appropriate, and our insistence upon the idea that such choices are our own.-Richard D. Alexander Shall we say that the plant does not know what it is doing merely because it has no eyes, or ears, or brains? If we say that it acts mechanically, and mechanically only, shall we not be forced to admit that sundry other and apparently very deliberate actions are also mechanical? If it seems to us that the plant kills and eats a fly mechanically, may it not seem to the plant that a man must kill and eat a sheep mechanically?-Samuel Butler, 1871 Is the brain, which is notably double in structure, a double organ, ”seeming parted, but yet a union in part.i.tion”?-Henry Maudsley8

Redundancy, as we have learned, is a key strategy deployed by the neocortex. But there is another level of redundancy in the brain, in that its left and right hemispheres, while not identical, are largely the same. Just as certain regions of the neocortex normally end up processing certain types of information, the hemispheres also specialize to some extent-for example, the left hemisphere typically is responsible for verbal language. But these a.s.signments can also be rerouted, to the point that we can survive and function somewhat normally with only one half. American neuropsychology researchers Stella de Bode and Susan Curtiss reported on forty-nine children who had undergone a hemispherectomy (removal of half of their brain), an extreme operation that is performed on patients with a life-threatening seizure disorder that exists in only one hemisphere. Some who undergo the procedure are left with deficits, but those deficits are specific and the patients have reasonably normal personalities. Many of them thrive, and it is not apparent to observers that they only have half a brain. De Bode and Curtiss write about left-hemispherectomized children who ”develop remarkably good language despite removal of the 'language' hemisphere.”9 They describe one such student who completed college, attended graduate school, and scored above average on IQ tests. Studies have shown minimal long-term effects on overall cognition, memory, personality, and sense of humor. They describe one such student who completed college, attended graduate school, and scored above average on IQ tests. Studies have shown minimal long-term effects on overall cognition, memory, personality, and sense of humor.10 In a 2007 study American researchers Shearwood McClelland and Robert Maxwell showed similar long-term positive results in adults. In a 2007 study American researchers Shearwood McClelland and Robert Maxwell showed similar long-term positive results in adults.11 A ten-year-old German girl who was born with only half of her brain has also been reported to be quite normal. She even has almost perfect vision in one eye, whereas hemispherectomy patients lose part of their field of vision right after the operation.12 Scottish researcher Lars Muckli commented, ”The brain has amazing plasticity but we were quite astonished to see just how well the single hemisphere of the brain in this girl has adapted to compensate for the missing half.” Scottish researcher Lars Muckli commented, ”The brain has amazing plasticity but we were quite astonished to see just how well the single hemisphere of the brain in this girl has adapted to compensate for the missing half.”

While these observations certainly support the idea of plasticity in the neocortex, their more interesting implication is that we each appear to have two brains, not one, and we can do pretty well with either. If we lose one, we do lose the cortical patterns that are uniquely stored there, but each brain is in itself fairly complete. So does each hemisphere have its own consciousness? There is an argument to be made that such is the case.

Consider split-brain patients, who still have both of their brain hemispheres, but the channel between them has been cut. The corpus callosum is a bundle of about 250 million axons that connects the left and right cerebral hemispheres and enables them to communicate and coordinate with each other. Just as two people can communicate closely with each other and act as a single decision maker while remaining separate and whole individuals, the two brain hemispheres can function as a unit while remaining independent.

As the term implies, in split-brain patients the corpus callosum has been cut or damaged, leaving them effectively with two functional brains without a direct communication link between them. American psychology researcher Michael Gazzaniga (born in 1939) has conducted extensive experiments on what each hemisphere in split-brain patients is thinking.

The left hemisphere in a split-brain patient usually sees the right visual field, and vice versa. Gazzaniga and his colleagues showed a split-brain patient a picture of a chicken claw to the right visual field (which was seen by his left hemisphere) and a snowy scene to the left visual field (which was seen by his right hemisphere). He then showed a collection of pictures so that both hemispheres could see them. He asked the patient to choose one of the pictures that went well with the first picture. The patient's left hand (controlled by his right hemisphere) pointed to a picture of a shovel, whereas his right hand pointed to a picture of a chicken. So far so good-the two hemispheres were acting independently and sensibly. ”Why did you choose that?” Gazzaniga asked the patient, who answered verbally (controlled by his left-hemisphere speech center), ”The chicken claw obviously goes with the chicken.” But then the patient looked down and, noticing his left hand pointing to the shovel, immediately explained this (again with his left-hemisphere-controlled speech center) as ”and you need a shovel to clean out the chicken shed.”

This is a confabulation. The right hemisphere (which controls the left arm and hand) correctly points to the shovel, but because the left hemisphere (which controls the verbal answer) is unaware of the snow, it confabulates an explanation, yet is not aware that it is confabulating. It is taking responsibility for an action it had never decided on and never took, but thinks that it did.

This implies that each of the two hemispheres in a split-brain patient has its own consciousness. The hemispheres appear not to be aware that their body is effectively controlled by two brains, because they learn to coordinate with each other, and their decisions are sufficiently aligned and consistent that each thinks that the decisions of the other are its own.

Gazzaniga's experiment doesn't prove that a normal individual with a functioning corpus callosum has two conscious half-brains, but it is suggestive of that possibility. While the corpus callosum allows for effective collaboration between the two half-brains, it doesn't necessarily mean that they are not separate minds. Each one could be fooled into thinking it has made all the decisions, because they would all be close enough to what each would have decided on its own, and after all, it does have a lot of influence on each decision (by collaborating with the other hemisphere through the corpus callosum). So to each of the two minds it would seem as if it were in control.

How would you test the conjecture that they are both conscious? One could a.s.sess them for neurological correlates of consciousness, which is precisely what Gazzaniga has done. His experiments show that each hemisphere is acting as an independent brain. Confabulation is not restricted to brain hemispheres; we each do it on a regular basis. Each hemisphere is about as intelligent as a human, so if we believe that a human brain is conscious, then we have to conclude that each hemisphere is independently conscious. We can a.s.sess the neurological correlates and we can conduct our own thought experiments (for example, considering that if two brain hemispheres without a functioning corpus callosum const.i.tute two separate conscious minds, then the same would have to hold true for two hemispheres with a functioning connection between them), but any attempt at a more direct detection of consciousness in each hemisphere confronts us again with the lack of a scientific test for consciousness. But if we do allow that each hemisphere of the brain is conscious, then do we grant that the so-called unconscious activity in the neocortex (which const.i.tutes the vast bulk of its activity) has an independent consciousness too? Or maybe it has more than one? Indeed, Marvin Minsky refers to the brain as a ”society of mind.”13 In another split-brain experiment the researchers showed the word ”bell” to the right brain and ”music” to the left brain. The patient was asked what word he saw. The left-hemisphere-controlled speech center says ”music.” The subject was then shown a group of pictures and asked to point to a picture most closely related to the word he was just shown. His right-hemisphere-controlled arm pointed to the bell. When he was asked why he pointed to the bell, his left-hemisphere-controlled speech center replied, ”Well, music, the last time I heard any music was the bells banging outside here.” He provided this explanation even though there were other pictures to choose from that were much more closely related to music.

Again, this is a confabulation. The left hemisphere is explaining as if it were its own a decision that it never made and never carried out. It is not doing so to cover up for a friend (that is, its other hemisphere)-it genuinely thinks that the decision was its own.

These reactions and decisions can extend to emotional responses. They asked a teenage split-brain patient-so that both hemispheres heard-”Who is your favorite...” and then fed the word ”girlfriend” just to the right hemisphere through the left ear. Gazzaniga reports that the subject blushed and acted embarra.s.sed, an appropriate reaction for a teenager when asked about his girlfriend. But the left-hemisphere-controlled speech center reported that it had not heard any word and asked for clarification: ”My favorite what?” When asked again to answer the question, this time in writing, the right-hemisphere-controlled left hand wrote out his girlfriend's name.

Gazzaniga's tests are not thought experiments but actual mind experiments. While they offer an interesting perspective on the issue of consciousness, they speak even more directly to the issue of free will. In each of these cases, one of the hemispheres believes that it has made a decision that it in fact never made. To what extent is that true for the decisions we make every day?

Consider the case of a ten-year-old female epileptic patient. Neurosurgeon Itzhak Fried was performing brain surgery while she was awa

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