In my opinion, a course in philosophy should be required in high school, and in college, regardless of major. Philosophy has been criticized as a lot of unfalsifiable, impractical self-indulgence. I couldn’t disagree more. Philosophy is very practical. Human beings require meaning in their lives. Without it we fall into self-destructive nihilism. Philosophy provides meaning without resorting to appeals to authority. Philosophy takes a lot of vague ideas about profound mysteries and provides us with tremendous clarity. It sharpens our focus and challenges our preconceptions. For example, most people have seen at least one of The Matrix series of movies, which introduced many to the philosophical concept of a brain in a vat. The basic idea is that if your brain were disembodied, sitting in a vat somewhere, with its inputs and outputs connected to the proper electrical signals, you would experience exactly what you are experiencing right now. There is absolutely no way to tell the difference.
Philosophers have spent a lot of time pondering the mystery of consciousness, and to a great extent it remains a mystery. Even defining it is tricky. On the one hand there is panpsychism, the notion that every piece of matter has some degree of consciousness. At the other extreme are philosophers like John Searle, who assert that only an organic brain is capable of generating consciousness. And then there is the zombie issue.
A philosophical zombie is an entity that behaves exactly the way a conscious being behaves. But it lacks consciousness. The argument has been made that since we can conceive of such an entity, this in itself means that it is possible in principle. But of course many philosophers suggest that this is a flawed argument. The brilliant philosopher David Chalmers agrees that zombies are logically possible. But he rejects the idea that they are possible in our universe. Because something doesn’t raise any contradictions does not mean it can actually exist in our reality. The concept of infinite speed doesn’t raise any logical contradictions. (And in fact, in a sense there IS no cosmic speed limit – see here). But this does not change the fact that no human being (or any object) can travel faster than light.
The zombie thought experiment really revolves around the debate over physicalism. Physicalism asserts that nothing non-physical exists. Therefore consciousness, which clearly exists, must be physical. But Chalmers, among others, argues that when we remove the functional aspects of consciousness, we are still left with something – experience. Explaining consciousness in terms of function is what he calls the easy problem. Function can indeed be accounted for in physical terms. The hard problem is accounting for personal experience. A zombie is an entity that does everything a conscious being does, but does not have experiences. The subjective character of experience, in this view, cannot be accounted for by physicalism, which requires that everything be objectively real.
It might seem obvious that there is a difference between the subjective and the objective. Objective reality, by definition, is something independent of the observer. But it is not at all obvious that thoughts, feelings, and experiences are not part of physical reality. The argument is made that these are merely higher-level ways of describing processes that are clearly physical. For example, take a chess-playing computer program. Hardly any thinking person believes that what it does cannot be described in physical terms. At one level, it is a matter of electrons moving through circuits. But it can also be described at a much higher level, in term of chess strategy – openings, sacrifices, and so on. Perhaps what we call subjective experience is just another way of describing physical processes – electrical impulses passing through the nervous system, neurotransmitters jumping across synapses, and so on.
Many philosophers reject the whole zombie idea. If you behave as if you can think, you are thinking. If you behave as if you are having experiences, you’re having them. There’s no such thing as simulated thinking. There’s no such thing as simulating having experiences. And all of it can be described in physical terms at some level. Keep in mind that a philosophical zombie version of Chalmers would behave EXACTLY as he does. It would laugh, cry, describe its dreams, and insist that it has experiences. It would carry on debates about philosophical zombies and the hard problem of consciousness. But it would be lying, to itself at least. It would just be simulating having experiences.
The issue arises all of the time in the field of artificial intelligence. Can a machine think? Can a machine have genuine emotions? Can a machine have experiences? There are those who insist that there is something about human consciousness that machines can never match. That the best they can do is give the APPEARANCE that they are matching it.
More than 70 years ago, computer scientist Alan Turing suggested a simple test to determine whether a machine is thinking. Have it answer questions. If a human being cannot distinguish between the machine and thinking human being, based solely on the answers, the machine is thinking. Obviously, the Turing Test is built on the belief that thinking cannot be simulated. That you can judge whether something, or someone, is thinking by their behavior. You don’t have to cut them open and see what they’re made of. It doesn’t matter what they’re made of. You can’t fake thinking.
There are other philosophers who insist that philosophical zombies are possible in our universe. That it is possible for a machine to give the appearance of thinking and having experiences, without actually thinking or having experiences. As a biologist, I’m surprised that a consideration of the characteristics and abilities of animals does not appear more often in these discussions. Is personal experience such a special thing? Can something have experiences without the ability to abstract?
Experiences, it seems to me, are, are intimately connected to the phenomenon of attention. Every moment we are awake, our senses are bombarded with lots of stimuli. Most of it does not get our attention. We are not CONSCIOUS of it. A lot of the reasoning performed by human beings is subconscious. In the process of solving a problem, many things just “come to us.” Often our brains are hard at work analyzing problems around us while our attention is elsewhere. There is the phenomenon of procedural memory; most of us have entered password or passcode while our attention was elsewhere. Our fingers “know” what buttons to push. Right now I am using procedural memory to type these words. Of course it isn’t our fingers that know, it’s our brains, but the information is being retrieved and utilized subconsciously.
And then there are dreams. Most of us dream, most of the time, without realizing we are dreaming. We are having “experiences,” but a big part of us is “not really there.” I am often struck by the fact that VERY unusual things happen in my dreams, yet it rarely seems to occur to me that I’m dreaming. It’s as if some part of my awareness has been turned off, and things that would never happen in my waking life are accepted as somehow normal. I’m not understanding the context. Yet the fact that I can usually remember at least some of my dreams demonstrates that I had some degree of awareness of what was happening. On the other hand, there is the phenomenon of lucid dreaming – dreaming with full awareness that one is dreaming. This has happened to me numerous times, and it’s as if a switch in my head suddenly turns on. Even in our waking lives, we sometimes daydream. If someone is talking to us and we are not paying attention, they might say, “You’re not really here.” It’s an interesting phrase, which acknowledges that a big part of who we are, or at least who we think we are, is our awareness, our attention.
If so much of what we do can be done at a subconscious level, doesn’t this argue that philosophical zombies are possible? Aren’t all of us “partial” zombies, limiting our conscious attention to specific things, while our subconscious minds are constantly taking in much more, analyzing problems, and even guiding some of our actions?
Many animals clearly show evidence of attention. Just watch the behavior of a mantid when a cricket walks nearby. It’s hard to believe that the insect isn’t having experiences. But is it conscious? My answer is yes and no. First of all, consciousness is not an all or nothing. It’s a matter of degree. Second, what we think of a consciousness really should be broken down into separate mental abilities – behavioral flexibility, personal experience, the ability to abstract. Perhaps the mantid is having an experience something like that we have in our dreams – giving its attention to stimuli, and responding to them, but not really understanding the context. The mantid doesn’t abstract. It doesn’t understand things like, “I am a predatory insect. The animal before me is also an insect. Insects include beetles, flies, and butterflies, among others. A caterpillar is an immature moth or butterfly. A spider is not an insect.” It doesn’t understand things like, “I am on the leaf of a tree, on the North American continent, on the planet earth, in a spiral arm of the Milky Way galaxy.” All of these things are about context, categories, relationships.
A human infant is probably much the same. It has experiences. It responds to stimuli. It can focus its attention on particular things. But its ability to abstract is quite limited. It doesn’t understand the big picture. It doesn’t understand very many categories or relationships. All of this comes about gradually, over time. The basic building blocks of consciousness are there, even in an earthworm. It responds to stimuli. It has rudimentary experiences. But its has very limited flexibility. It cannot abstract. A crocodile is more flexible. A gorilla more still. A gorilla has the ability to abstract in a limited way, much as a newborn human. The necessary basic elements are the ability to store and process information, and some kind of sensory system to acquire information about the environment. As these become more sophisticated, experiences become richer, and flexibility increases. Eventually a point is reached where the organism is able to abstract. The organism creates a mental model of itself. All of these are different abilities – mental flexibility, experiences, the ability to abstract. But they arise from the basic structure – the ability to acquire, store, and process information.
There is one realm of human activity that does seem to give considerable credence to the idea of philosophical zombies. Acting. Actors can give responses and display emotions that do not reflect their internal thoughts and emotions. It is a simulation. Related to this is the phenomenon of the psychopath. Psychopaths do not seem to feel certain emotions that most of us feel, most notably empathy. But they are able to give the appearance of feeling these emotions, at least sufficiently to cope. They seem to do this by observing the behavior of others in specific contexts and imitating it. Does this demonstrate that philosophical zombies can exist in our reality? Well, yes and no. It does appear that human beings can behave in such a way as to simulate specific emotions and experiences. Presumably an intelligent being can learn to mimic human behaviors by studying humans carefully. But there remains a problem.
In one of the episodes from the old Star Trek series, 4 of the officers get flung into a mirror universe, while their counterparts in that universe get thrown into ours. In the mirror universe, there is no United Federation of Planets. There is an empire filled with barbarians who routinely stab each other in the back and employ terror to keep individual planetary systems in line. The 4 officers are able to blend in, at least for a while. But their counterparts in our universe are discovered immediately. When the captain returns to his own universe, he asks Mr. Spock how he was able to identify his counterpart so quickly. “It was far easier for you, as civilized men, to behave as barbarians, than for them, as barbarians, to behave as civilized men,” Mr. Spock explains.
The same principle applies to thinking, conscious experience, and the ability to abstract. A human being can behave in a robotic fashion, as some very talented mimes can demonstrate. For a robot to behave like a human, and do it without actually thinking, having experiences, or abstracting – well, that’s a good trick. Many of the cues we use to identify a thinking human being involve flexibility, the hallmark of intelligence. Human beings use what is called commonsense reasoning. This is the ability to make assumptions about how the real world operates and apply those assumptions to specific problems. Human minds are packed full of general knowledge and assumptions about the world, most of which turn out to be correct, and this enables us to navigate our surroundings with great ease. It gives us tremendous flexibility and the ability to quickly interpret novelties in the environment. Human beings use what are called heuristics – shortcuts that enable us to quickly generate solutions that are approximate, rather than trying to do a time-consuming analysis driving toward a “perfect” solution. Human beings are able to see the big picture – every time we examine a specific object or do a specific task, we have an idea of how it fits into a much broader context.
Most animals are slaves to their behavioral programming. This is why a moth flies into a flame. It is why billions of animals are killed every year on roadways. Human beings are much better at avoiding cars than dogs are, even though dogs are faster. They often panic when a car approaches, darting out at the last moment. Panic is an ancient flight response, built into many species, including ours. But a human being understands that the car will very likely stay along a very specific path. A psychopath may not feel a particular emotion. But the argument could be made that only because the psychopath has tremendous mental flexibility AND experiences AND the ability to abstract is he able to convincingly simulate those emotions that he doesn’t feel.
When we create systems of sufficient complexity, programmed with goals and the ability to learn, I think we will find that thinking, conscious experience, and the ability to abstract are inevitable results of what these systems do. That conscious experience and the “self” are merely virtual realities created by such systems, just as virtual realities can be created by computer systems today. I often think of a flight simulator. When a flight simulator is running, and we turn off the monitor, where is the plane? It is exactly where it was, in a virtual landscape. The simulator creates virtual space, virtual time, and virtual objects. If the plane were equipped with a sufficiently sophisticated brain and sense organs, it would have experiences within this virtual reality – a secondary virtual reality within the larger one. It would create a mental model of itself within this virtual reality in relation to its environment. It would have thoughts, experiences, and a sense of self regardless of whether we turned on the monitor. To the plane, its virtual reality and its sense of self would be as real as ours are to us.
The mere fact that we can create virtual realities should tell us that the basic elements are there. The next step is to create virtual “organisms” which respond to stimuli and use information processing to reach specific goals. This will lead to virtual beings that have experiences, and eventually, consciousness. None of this will require the construction of these objects in our physical reality, only the information processing systems to produce them in virtual reality.