What is consciousness? Can consciousness have evolved, naturally, like the rest of our bodies? Why are we conscious? Would we be better off as unconscious zombies? One thing I know for sure: If we’d be better off as zombies, we’d be zombies. It’s much, much cheaper to make us that way, and in the game of life, price sells. Therefore there must be a powerful reason we have this crazy little thing called a mind.
What is consciousness? Can consciousness have evolved, naturally, like the rest of our bodies? These are two questions scientists and philosophers have been grappling with since Darwin published his famous theory of natural selection, and, unfortunately, we have yet to come up with a satisfactory answer. For example, Bernado Kastrup, a Dutch computer scientist and philosopher, believes that consciousness could not have evolved at all. He laid out his concerns last year in a post on IaI.tv News.
Essentially, Mr. Kastrup makes two claims. First, that evolution is a materialist worldview, holding that the process of evolution, natural selection, sexual selection, niche selection, etc. requires quantifiable outputs to act on. “All chains of cause and effect in nature must be describable purely in terms of quantities. Whatever isn’t a quantity cannot be part of our physical models and therefore—insofar as such models are presumed to be causally-closed—cannot produce effects. According to materialism, all functions rest on quantities.” In his view, evolution relies on the difference in these quantities as expressed by genes to function.
Second, he holds that consciousness is non-quantifiable and unitary. Consciousness “is eminently qualitative, not quantitative. There is something it feels like to see the colour red, which is not captured by merely noting the frequency of red light. If we were to tell Helen Keller that red is an oscillation of approximately 4.3*1014 cycles per second, she would still not know what it feels like to see red. Analogously, what it feels like to listen to a Vivaldi sonata cannot be conveyed to a person born deaf, even if we show to the person the sonata’s complete power spectrum.” He continues to assert “it must make no difference to the survival fitness of an organism whether the data processing taking place in its brain is accompanied by experience or not: whatever the case, the processing will produce the same effects; the organism will behave in exactly the same way and stand exactly the same chance to survive and reproduce.”
From this, Mr. Kastrup concludes “phenomenal consciousness cannot have been favoured by natural selection. Indeed, it shouldn’t exist at all; we should all be unconscious zombies, going about our business in exactly the same way we actually do, but without an accompanying inner life. If evolution is true—which we have every reason to believe is the case—our very sentience contradicts materialism.” To be sure, Mr. Kastrup does not specifically say that consciousness is unitary, meaning you either have it or you don’t, as opposed to being divisible into degrees and component parts, but it is strongly implied in his thinking by the use of the word “sentience,” the capacity to feel, perceive or experience subjectively, and the examples he provides. Consciousness enables attention, discriminates episodic memory, and motivates behavior. These are all complex, higher order phenomena, requiring more than the mere experience of the color red, more on that in a moment.
In my opinion, Mr. Kastrup’s conclusion is fatally flawed for two reasons. First, we should not assume that consciousness is a unitary, you have it or you don’t phenomenon. While it certainly feels that way most of the time, there is reason to believe that much like our bodies are composed of different organs that work together for us to live, breath, and think, consciousness itself is composed of different constituent parts. If that is the case, we can look at the evolutionary advantage of each part, as we would with any other adaptation and then consider how that part arose individually, each with its own benefit, before being combined into what we consider human consciousness.
Second, neither should we assume that experience is non-quantifiable and provides no advantage for evolution to act on. Here Mr. Kastrup asserts that “Experiences are felt qualities—which philosophers and neuroscientists call ‘qualia’—not fully describable by abstract quantities.” This is a two part argument, first that we cannot quantify experience and second, that an unconscious zombie would be just as evolutionary “fit,” but both are untested and likely untrue as we shall see.
Let’s address whether consciousness is indeed unitary, you have it or you don’t, first. Generally speaking, when scientists and philosophers refer to consciousness and sentience, they are describing a phenomena unique to humans and perhaps our cousins the great apes. Further, they are referring to a specifically self-referential aspect of this phenomenon, hinging on an ability to know one’s self as being different from others and to understand that our own experiences are unique. In this way, we both experience pain and are aware it’s painful. We know what pain is even while we’re not in pain. This capacity appears to be extremely limited; the great majority of animals do not have it.
At the same time, there is no reason to believe that this higher order capacity is not the sum of constituent parts and that these building blocks are not far more widespread in the animal kingdom. Mr. Kastrup uses the word “qualia” to describe “felt qualities,” seeing red, hearing a sonata, etc., but qualia and unitary, higher-order consciousness are not the same thing. Higher order consciousness certainly requires qualia, but can you have qualia without higher order consciousness? Can you experience a color without reflecting on it?
It seems obvious to me that you can. When you are black out drunk for example, you partake of the experience and not the recall, or consider an animal like a dog. I am aware of no philosopher or scientist that would assert a dog is conscious or sentient in the same way as a human, but is there any doubt that they experience the world in their own limited way and, in a lot of ways, it is the same as we do? For starters, a dog’s nervous system is composed of the exact same parts as ours, built from the same proteins, using many of the same genes. Further, their neurons function the same way, using identical chemical pathways and their senses use the same systems. The differences are all of degree and wiring, not of any fundamental biological process, prompting the question, does a dog have qualia?
I believe they have to. There is no doubt in my mind that a dog experiences pleasure and pain, fear and excitement, and more in response to environmental stimuli; moreover they can store that stimuli and react to it at a later time. One need only watch one enter a room, take stock of the situation, and respond, or watch them run out of the room when they snag a snack. Their responses to their environment aren’t the least bit robotic or “zombie” like. Rather, they “feel” the environment intensely and make decisions based on these feelings. In this manner, they have their favorite spots in the house at their favorite time of the day, toys, treats, people, and more. Their experience is to a large extent raw feeling, almost everything they do is tagged by an underlying emotion and determined to be preferable or avoidable, nor can they manipulate those experiences in any kind of narrative like we can.
Yet, there is no reason to believe they experience these things fundamentally differently than we do as the experience is unfolding. Their eyes translate photons into perception in the same exact way, as does their sense of smell, touch, and hearing. Any difference in the sensory system and nervous system that processes it are incidental, a different model of automobile as opposed to comparing a car to a horse and buggy. The main difference is what comes after the experience itself; the higher order functions we can apply to the underlying qualia. I know some will likely argue that dogs are exhibiting mere stimulus responses, but their behavior is far more complicated than that. A dog has a place to sleep at night, participates in a day to day routine, displays preference for some parts of the day more than others, all behaviors that rely on prior experience.
Putting this another way, did human evolution “invent” a new way to experience a color or the smell of food, something fundamentally different from our canine friends? Or did human evolution take advantage of pre-existing structures and combine them in higher-order ways?
If dogs experience qualia like I am suggesting, then it necessarily follows that consciousness has constituent parts, building blocks. Qualia is one of them and is likely the one that is most shared across the animal kingdom given that sensory apparatus and memory storage is quite similar across mammals for instance. I could have used a cat in my thought experiment instead of a dog. Episodic memory for example is another, likely far less shared with our animal friends. Others could include self-awareness, symbolic interpretation, multi-step problem solving, etc. This means that different aspects of consciousness evolved separately, at different times, and there is likely an evolutionary advantage to each.
In support of this view, these broad categories could be broken down further. For example, episodic memory includes the ability to recall things not physically present and to present information not directly in response to the associated stimulus. There are three known, almost completely unrelated species that do this: Humans, crows, and bees. Of course, bees perform the task quite differently than we do, but they are still capable of what the vast majority of animals are not: They can remember the location and quantity of a potential food supply and report it back to the hive. The hive itself can then evaluate the relative merit of each of the reported food supplies and make a decision. I am not aware of any philosopher or scientist who thinks this process did not evolve naturally, and I would assert that if aspects of consciousness have evolutionary value for everything from dogs to bees, the same must be true of humans.
The second part of Mr. Kastrup’s argument is a bit trickier to tackle, whether qualia are quantifiable and whether they have an evolutionary benefit. To be clear, qualia are not currently quantifiable. That is surely true, but a lack of our current ability to quantify them does not imply that they are inherently unquantifiable. For example, there are scientists like Lee Smolin who believe they have a mathematical representation and indeed that representation is essential to a better understanding of the universe itself. From my perspective, I see no reason why they would not be quantifiable, at least in parts, meaning I do not believe we can quantify every qualia a person experiences in their lifetime time, any more than we can quantify every molecule in a human body.
Like molecules in the human body, however, there is no need to quantify all qualia to believe they are measurable. All that would be needed is description for how we experience qualia at the level of our neurons and any supporting systems. While we don’t have such a framework yet, there is no reason to believe developing one is impossible. There’s another way to look at this: We can invert Mr. Kastrup’s argument to prove that qualia are quantifiable, that is we can demonstrate that qualia, in fact, have a measurable evolutionary benefit. If they have such a benefit, something about them must be measurable and quantifiable. The question then becomes: What are the evolutionary benefits of qualia?
To answer that question, we have to consider the evolution of the nervous system itself. In the 1960’s, neuroscientist Paul D. MacLean proposed a triune model for brains in higher animals. He believed that animal brains rely on three complexes, the lizard, limbic, and neomammalian. Roughly speaking, the lizard brain was responsible for instinctive behavior, aggression, dominance, territoriality, etc. The limbic system then added motivation and emotion, while the neomammalian provides language, abstraction, and planning, the sorts of things we normally associate with human consciousness. While this approach has some utility for thinking about different behaviors in the animal kingdom, it is generally seen as a gross oversimplification of biological reality.
I agree with that; the real biological world is a lot messier, but for our purposes here, it does make one crucial, indisputable point: The evolution of the brain has to act on the structures that came before. Higher order consciousness does not arise on its own, rather it is layered on top of systems that were already present, meaning qualia must have arisen from some more primitive mode of perception. What could that primitive mode be?
I can’t say I have a definitive answer, but I do have a suggestion for a line of inquiry. There are a set of responses in human and other animal behavior that bypass consciousness entirely. For example, we remove our hand from a hot stove before we actually experience the pain. This unconscious avoidance is widely shared and well understood. The nervous system causes our hand to move before the pain signal even reaches the brain; the nervous system loops back on itself in our spine, one message goes back to the hand, move now, the other goes to the brain and triggers the feeling of pain.
This set up clearly has a survival benefit. It takes longer for the brain to process the pain than for the body to react; that crucial time differential could result in a much more serious injury, therefore it is better to react first, experience later. For the purposes of our argument, it also has the benefit of evolving much, much earlier than the conscious experience of pain. All animals that I am aware of, even insects, instinctually move away from threats. In MacLean’s formulation, this would be part of the lizard brain. The higher order functions, the qualia, didn’t come until much later.
There are other unconscious responses that are far more complicated and require more sophisticated processing systems. For example, flinching or reacting to something “out of the corner of your eye.” In both cases, the brain responds to stimuli before we consciously recognize it. While it is similar to the pain response, the underlying processes are much more sophisticated than a simple nerve loop because the retina and supporting systems need to process the image first. The relevant information for the unconscious response is extracted before conscious awareness dawns.
At the same time, we can assume a similar evolutionary benefit. Moreover, we can imagine an animal that evolved to discard these processes and, instead, route everything through “central processing” prior to reacting. This would have been easy enough to achieve given that the stimulus response ultimately terminates in the brain; all that would be required is bypassing the unconscious response. As that has not occurred, however, it is safe to assume there was an obvious evolutionary benefit to preserving the unconscious reaction, meaning consciousness, or qualia to be specific in this case, alone was not enough.
This is how we can arrive at a potential evolutionary benefit of qualia themselves. Given the brain has unconscious processing systems for emotions and reactions, and given those systems have obvious evolutionary benefits, why would the rise of higher order, more discriminating perception not take advantage of the lower order functions? Meaning, wouldn’t an organism reap the most advantage if they could somehow combine the two?
In my opinion, this is precisely the function and therefore the evolutionary advantage of qualia. Qualia seamlessly connect the conscious details of the experience with our unconscious reactions. This allows the brain to root every experience in a corresponding emotion, pleasure or pain, joy or sorrow, etc. Since we have established that unconscious reactions can be beneficial evolutionarily speaking, the same logic must apply to qualia. Consider the feeling of pain after putting a hand on a stove. What more advantageous way is there to encourage an organism to avoid the situation in the future than imprinting the experience with the pain? Putting this another way, how is zombie-like, purely analytic experience more advantageous than experience embedded in the broader array of emotions and the supporting nervous systems?
Rather than encoding simply one aspect of the experience, the details subject to conscious analysis, qualia encode two aspects, the details plus the unconscious feeling. I would argue that this greatly increases their value and utility, both for the qualia themselves and also for the higher order conscious systems that manipulate them. This way, when we recall the memory of an experience, we have access to the specifics and the feeling at the same time. The two cannot be easily separated. I should note that this is broadly supported by how recall itself works, where the brain literally “replays” an experience through the sensory systems. Given much of those systems is unconscious, the replay must necessarily include those aspects and qualia encapsulates them.
Further, it is unclear to me how else these higher order functions would evolve in the first place without being embedded in the existing systems. Clearly, unconscious, zombie-like reactions came first and were present long before qualia arrived on the scene. Therefore, qualia must be built on those very systems and thus are inseparable from the emotional component, the feeling of what happens as important as the detail of what happened, indeed it arose first in evolutionary terms. One important note to make: I am specifically referring to evolutionary advantages, not rational or analytic advantages. For a scientist, there might be some benefit for being a purely rational data processing machine; scientists, however, came long after humans evolved, therefore the benefit of qualia and consciousness in general must apply to a survival and reproductive advantage.
To be clear, it is not at all clear to me how this hypothesis could be tested. It is impossible to determine precisely how our ancestors truly felt about anything, much less some prehistoric canine and the evolutionary benefit of it. At the same time, one can imagine a comparative analysis between modern day organisms and the systems of perception and memory formation. If we could isolate the systems involved in perceiving and storing an experience, we can quantify it and if we can quantify it for one animal, we can compare it to another. We can also look at how these structures are encoded in our genes and compare those as well. One can also imagine a simulation, where we compared simple computer programs that encoded straight detail versus detail plus simple emotion as one mathematical structure, and attempt to test whether or not the zombie model is truly equivalent to the qualia model, bearing in mind the benefits must be related to survival and reproduction in a non-civilized state of nature.
Lastly, I should point out that I find comparisons between how computers process information and how living organisms evolved to process information unsatisfactory. Mr. Kastrup uses the comparison of computers to illustrate how information can be processed without qualia. What he says there is true, but computers were not built from the ground up by an evolutionary process. Therefore, there was no existing set of sensory apparatus, nervous systems, and unconscious reactions to build upon, in fact that must’ve been built upon, and these comparisons necessarily miss the point that qualia and experience itself can be seen as a bridge between the conscious and unconscious.
Ultimately, I remain confident that consciousness is explainable in evolutionary terms and has a quantifiable benefit for selection purposes. I think if we consider that consciousness is not a unitary phenomenon that sprung into being in its entirety, we can look at the possible forces that drove the evolution of each part, the same way we look at the evolution of different parts of the body. I also think we can consider that qualia themselves have intrinsic evolutionary value by combining different sensory and perceptive properties in the same “unit.” No matter the course of future discourse or whether these ideas will stand the test of time, it is clear to me that the way forward is to reject the notion that consciousness is some ghost in the machine, rather than an intrinsic part of the machine itself, inseparable from it.
One thing remains true regardless: Evolution is the ultimate miser and brains are expensive, consuming some 20% of our body’s energy while weighing only 2%. A significant portion of this expenditure is for our massive frontal lobes and the constant flow of our thoughts. It is inconceivable to me that our ancient ancestors, some two million years ago, living literally hand to mouth and scavenging on dead mastodon’s for sustenance, would have paid that kind of price and received no benefit in return. If we’d be better off as zombies, we’d be zombies. It’s much, much cheaper to make us that way, and in the game of life, price sells. Therefore there must be a powerful reason we have this crazy little thing called a mind.