by Ray Kurzweil
Now suppose as we destructively scan Jack, we simultaneously install this information into the new Jack. We can consider this a process of “transferring” Jack to his new brain and body. So one might say that Jack is not destroyed, just transferred into a more suitable embodiment. But is this not equivalent to scanning Jack noninvasively subsequently instantiating the new Jack and then destroying the old Jack? If that sequence of steps basically amounts to killing the old Jack, then this process of transferring Jack in a single step must amount to the same thing. Thus we can argue that any process of transferring Jack amounts to the old Jack committing suicide, and that the new Jack is not the same person.
The concept of scanning and reinstantiation of the information is familiar to us from the fictional “beam me up” teleportation technology of Star Trek. In this fictional show, the scan and reconstitution is presumably on a nanoengineering scale, that is, particle by particle, rather than just reconstituting the salient algorithms of neural-information processing envisioned above. But the concept is very similar. Therefore, it can be argued that the Star Trek characters are committing suicide each time they teleport, with new characters being created. These new characters, while essentially identical, are made up of entirely different particles, unless we imagine that it is the actual particles being beamed to the new destination. Probably it would be easier to beam just the information and use local particles to instantiate the new embodiments. Should it matter? Is consciousness a function of the actual particles or just of their pattern and organization?
We can argue that consciousness and identity are not a function of the specific particles at all, because our own particles are constantly changing. On a cellular basis, we change most of our cells (although not our brain cells) over a period of several years.2 On an atomic level, the change is much faster than that, and does include our brain cells. We are not at all permanent collections of particles. It is the patterns of matter and energy that are semipermanent (that is, changing only gradually), but our actual material content is changing constantly, and very quickly We are rather like the patterns that water makes in a stream. The rushing water around a formation of rocks makes a particular, unique pattern. This pattern may remain relatively unchanged for hours, even years. Of course, the actual material constituting the pattern—the water—is totally replaced within milliseconds. This argues that we should not associate our fundamental identity with specific sets of particles, but rather the pattern of matter and energy that we represent. This, then, would argue that we should consider the new Jack to be the same as the old Jack because the pattern is the same. (One might quibble that while the new Jack has similar functionality to the old Jack, he is not identical. However, this just dodges the essential question, because we can reframe the scenario with a nanoengineering technology that copies Jack atom by atom rather than just copying his salient information-processing algorithms.)
Contemporary philosophers seem to be partial to the “identity from pattern” argument. And given that our pattern changes only slowly in comparison to our particles, there is some apparent merit to this view. But the counter to that argument is the “old Jack” waiting to be extinguished after his “pattern” has been scanned and installed in a new computing medium. Old Jack may suddenly realize that the “identity from pattern” argument is flawed.
MIND AS MACHINE VERSUS MIND BEYOND MACHINE
Science cannot solve the ultimate mystery of nature because in the last analysis we are part of the mystery we are trying to solve.
—Max Planck
Is all what we see or seem, but a dream within a dream?
—Edgar Allan Poe
What if everything is an illusion and nothing exists? In that case, I definitely overpaid for my carpet.
—Woody Allen
The Difference Between Objective and Subjective Experience
Can we explain the experience of diving into a lake to someone who has never been immersed in water? How about the rapture of sex to someone who has never had erotic feelings (assuming one could find such a person)? Can we explain the emotions evoked by music to someone congenitally deaf? A deaf person will certainly learn a lot about music: watching people sway to its rhythm, reading about its history and role in the world. But none of this is the same as experiencing a Chopin prelude.
If I view light with a wavelength of 0.000075 centimeters, I see red. Change the wavelength to 0.000035 centimeters and I see violet. The same colors can also be produced by mixing colored lights. If red and green lights are properly combined, I see yellow. Mixing pigments works differently from changing wavelengths, however, because pigments subtract colors rather than add them. Human perception of color is more complicated than mere detection of electromagnetic frequencies, and we still do not fully understand it. Yet even if we had a fully satisfactory theory of our mental process, it would not convey the subjective experience of redness, or yellowness. I find language inadequate for expressing my experience of redness. Perhaps I can muster some poetic reflections about it, but unless you’ve had the same encounter, it is really not possible for me to share my experience.
So how do I know that you experience the same thing when you talk about redness? Perhaps you experience red the way I experience blue, and vice versa. How can we test our assumptions that we experience these qualities the same way? Indeed, we do know there are some differences. Since I have what is misleadingly labeled “red-green” color-blindness, there are shades of color, that appear identical to me that appear different to others. Those of you without this disability apparently have a different experience than I do. What are you all experiencing ? I’ll never know.
Giant squids are wondrous sociable creatures with eyes similar in structure to humans (which is surprising, given their very different phylogeny) and possessing a complex nervous system. A few fortunate human scientists have developed relationships with these clever cephalopods. So what is it like to be a giant squid? When we see it respond to danger and express behavior that reminds us of a human emotion, we infer an experience that we are familiar with. But what of their experiences without a human counterpart?
Or do they have experiences at all? Maybe they are just like “machines”—responding programmatically to stimuli in their environment. Maybe there is no one home. Some humans are of this view—only humans are conscious; animals just respond to the world by “instinct,” that is, like a machine. To many other humans, this author included, it seems apparent that at least the more evolved animals are conscious creatures, based on empathetic perceptions of animals expressing emotions that we recognize as correlates of human reactions. Yet even this is a human-centric way of thinking in that it only recognizes subjective experiences with a human equivalent. Opinion on animal consciousness is far from unanimous. Indeed, it is the question of consciousness that underlies the issue of animal rights. Animal rights disputes about whether or not certain animals are suffering in certain situations result from our general inability to experience or measure the subjective experience of another entity.3
The. not uncommon view of animals being “just machines” is disparaging to both animals and machines. Machines today are still a million times simpler than the human brain. Their complexity and subtlety today is comparable to that of insects. There is relatively little speculation on the subjective experience of insects, although again, there is no convincing way to measure this. But the disparity in the capabilities of machines and the more advanced animals, such as the Homo sapiens sapiens subspecies, will be short-lived. The unrelenting advance of machine intelligence, which we will visit in the next several chapters, will bring machines to human levels of intricacy and refinement and beyond within several decades. Will these machines be conscious?
And what about free will—will machines of human complexity make their own decisions, or will they just follow a program, albeit a very complex one? Is there a distinction to be made here?
The issue of consciousness lurks behind other vexing is
sues. Take the question of abortion. Is a fertilized egg cell a conscious human being? How about a fetus one day before birth? It’s hard to say that a fertilized egg is conscious or that a full-term fetus is not. Pro-choice and pro-life activists are afraid of the slippery slope in between these two definable ledges. And the slope is genuinely slippery—a human fetus develops a brain quickly, but it’s not immediately recognizable as a human brain. The brain of a fetus becomes more humanlike gradually The slope has no ridges to stand on. Admittedly, other hard-to-define questions such as human dignity come into the debate, but fundamentally, the contention concerns sentience. In other words, when do we have a conscious entity?
Some severe forms of epilepsy have been successfully treated by surgical removal of the impaired half of the brain. This drastic surgery needs to be done during childhood before the brain has fully matured. Either half of the brain can be removed, and if the operation is successful the child will grow up somewhat normally Does this imply that both halves of the brain have their own consciousness? Perhaps there are two of us in each intact brain who hopefully get along with each other. Maybe there is a whole panoply of consciousnesses lurking in one brain, each with a somewhat different perspective. Is there a consciousness that is aware of mental processes that we consider unconscious?
I could go on for a long time with such conundrums. And indeed, people have been thinking about these quandaries for a long time. Plato, for one, was preoccupied with these issues. In the Phaedo, The Republic, and Theaetetus, Plato expresses the profound paradox inherent in the concept of consciousness and a human’s apparent ability to freely choose. On the one hand, human beings partake of the natural world and are subject to its laws. Our brains are natural phenomena and thus must follow the cause-and-effect laws manifest in machines and other lifeless creations of our species. Plato was familiar with the potential complexity of machines and their ability to emulate elaborate logical processes. On the other hand, cause-and-effect mechanics, no matter how complex, should not, according to Plato, give rise to self-awareness or consciousness. Plato first attempts to resolve this conflict in his theory of the Forms: Consciousness is not an attribute of the mechanics of thinking, but rather the ultimate reality of human existence. Our consciousness, or “soul,” is immutable and unchangeable. Thus, our mental interaction with the physical world is on the level of the “mechanics” of our complicated thinking process. The soul stands aloof.
But no, this doesn’t really work, Plato realizes. If the soul is unchanging, then it cannot learn or partake in reason, because it would need to change to absorb and respond to experience. Plato ends up dissatisfied with positing consciousness in either place: the rational processes of the natural world or the mystical level of the ideal Form of the self or soul.4
The concept of free will reflects an even deeper paradox. Free will is purposeful behavior and decision making. Plato believed in a “corpuscular physics” based on fixed and determined rules of cause and effect. But if human decision making is based on such predictable interactions of basic particles, our decisions must also be predetermined. That would contradict human freedom to choose. The addition of randomness into the natural laws is a possibility, but it does not solve the problem. Randomness would eliminate the predetermination of decisions and actions, but it contradicts the purposefulness of free will, as there is nothing purposeful in randomness.
Okay, let’s put free will in the soul. No, that doesn’t work either. Separating free will from the rational cause-and-effect mechanics of the natural world would require putting reason and learning into the soul as well, for otherwise the soul would not have the means to make meaningful decisions. Now the soul is itself becoming a complex machine, which contradicts its mystical simplicity.
Perhaps this is why Plato wrote dialogues. That way he could passionately express both sides of these contradictory positions. I am sympathetic to Plato’s dilemma: None of the obvious positions is really sufficient. A deeper truth can be perceived only by illuminating the opposing sides of a paradox.
Plato was certainly not the last thinker to ponder these questions. We can identify several schools of thought on these subjects, none of them very satisfactory.
The “Consciousness Is Just a Machine Reflecting on Itself” School
A common approach is to deny the issue exists: Consciousness and free will are just illusions induced by the ambiguities of language. A slight variation is that consciousness is not exactly an illusion, but just another logical process. It is a process responding and reacting to itself. We can build that in a machine: just build a procedure that has a model of itself, and that examines and responds to its own methods. Allow the process to reflect on itself. There, now you have consciousness. It is a set of abilities that evolved because self-reflective ways of thinking are inherently more powerful.
The difficulty with arguing against the “consciousness is just a machine reflecting on itself” school is that this perspective is self-consistent. But this viewpoint ignores the subjective viewpoint. It can deal with a person’s reporting of subjective experience, and it can relate reports of subjective experiences not only to outward behavior but to patterns of neural firings as well. And if I think about it, my knowledge of the subjective experience of anyone aside from myself is no different (to me) than the rest of my objective knowledge. I don’t experience other people’s subjective experiences; I just hear about them. So the only subjective experience this school of thought ignores is my own (that is, after all, what the term subjective experience means). And, hey, I’m only one person among billions of humans, trillions of potentially conscious organisms; all of whom, with just one exception, are not me.
But the failure to explain my subjective experience is a serious one. It does not explain the distinction between 0.000075 centimeter electromagnetic radiation and my experience of redness. I could learn how color perception works, how the human brain processes light, how it processes combinations of light, even what patterns of neural firings this all provokes, but it still fails to explain the essence of my experience.
The Logical Positivists5
I am doing my best to express what I am talking about here but unfortunately the issue is not entirely effable. D. J. Chalmers describes the mystery of the experienced inner life as the “hard problem” of consciousness, to distinguish this issue from the “easy problem” of how the brain works.6 Marvin Minsky observed that “there’s something queer about describing consciousness: Whatever people mean to say, they just can’t seem to make it clear.” That is precisely the problem, says the “consciousness is just a machine reflecting on itself” school—to speak of consciousness other than as a pattern of neural firings is to wander off into a mystical realm beyond any hope of verification.
This objective view is sometimes referred to as logical positivism, a philosophy codified by Ludwig Wittgenstein in his Tractatus Logico-Philosophicus.7 To the logical positivists, the only things worth talking about are our direct sensory experiences, and the logical inferences that we can make therefrom. Everything else “we must pass over in silence,” to quote Wittgenstein’s last statement in his treatise.
Yet Wittgenstein did not practice what he preached. Published in 1953, two years after his death, his Philosophical Investigations defined those matters worth contemplating as precisely those issues he had earlier argued should be passed over in silence.8 Apparently he came to the view that the antecedents of his last statement in the Tractatus—what we cannot speak about—are the only real phenomena worth reflecting upon. The late Wittgenstein heavily influenced the existentialists, representing perhaps the first time since Plato that a major philosopher was successful in illuminating such contradictory views.
I Think, Therefore I Am
The early Wittgenstein and the logical positivists that he inspired are often thought to have their roots in the philosophical investigations of René Descartes.9 Descartes’s famous dictum “I think, therefore I am” has often been cited
as emblematic of Western rationalism. This view interprets Descartes to mean “I think, that is, I can manipulate logic and symbols, therefore I am worthwhile.” But in my view, Descartes was not intending to extol the virtues of rational thought. He was troubled by what has become known as the mind-body problem, the paradox of how mind can arise from nonmind, how thoughts and feelings can arise from the ordinary matter of the brain. Pushing rational skepticism to its limits, his statement really means “I think, that is, there is an undeniable mental phenomenon, some awareness, occurring, therefore all we know for sure is that something—let’s call it I—exists.” Viewed in this way, there is less of a gap than is commonly thought between Descartes and Buddhist notions of consciousness as the primary reality.
