A short story on the philosophy of mind
In one of the most extraordinary events in the history of humanity, contact was made with a sentient extraterrestrial intelligence residing some light years away from Earth. Though an in-person meeting would not be possible any time soon given the vast distance involved, a radio communication channel was established, and both species enthusiastically worked around the clock to develop a common protocol for the stream of information that would follow. Successfully coordinating this stream between two remote parties that have no pre-existing knowledge of each other’s standards and conventions was a monumental achievement, a credit to the dedication and great minds of both species.
Communication patterns were established first around a basic numbering system, followed by simple mathematical and logical operators. This expanded to coordinate systems and graphs, and other more complex constructs. Common points of reference were tested, such as familiar physics and chemistry equations, astronomical reference points, knowledge of molecules and the sub-atomic world, and so on. Upon these shared references, a basic common language could be constructed, with a meaningful grammar.
With exchanges taking many years to go back and forth, it was important to be clear and concise with communication. On Earth, teams of cross-disciplinary experts worked together for weeks and months to form and vet each single question and response. Many multiples of conversations were conducted in parallel, with carefully crafted questions being added to the inter-stellar stream periodically for years before answers to them finally arrived.
The alien species were soon dubbed the ‘zombies’ due to their immediately apparent inability or disinterest in describing their perceived experience. A basic question such as “how are you?” would be answered with “I’m speaking with you of course!” and “what is it like on your planet?” with “we are progressing well with our current tasks.” Initially, this appeared mostly as a language barrier – it took some time to figure out how to ask the right questions in order to get useful answers.
The zombies confirmed that we were their first extraterrestrial contact as well, and they appeared as excited as us about the event. Scientists on both sides eagerly shared technological innovations, scientific discoveries, and mathematical knowledge. Both species had made large strides on many fronts, though due to very different environments and histories, our areas of expertise differed markedly. For example, humans were comparatively adept at flight while zombies mastered the oceans. Humans helped to advance the zombies’ knowledge of physics, while the zombies greatly advanced our knowledge of chemistry. However, both species felt like they had made great progress in every field of science and technology on their own, and would likely eventually have come across all the same discoveries even if we had never met. One area was a notable exception to this.
While both species had many questions for each other, the zombies seemed particularly keen to know if we, like them, experienced our existence in a certain way – interpreting the world around us and the world inside us, as they do. Due to language barriers, it was not immediately clear what they meant, but soon philosophers came to interpret the aliens’ question as being about consciousness, and in particular, qualia. However, after providing our best descriptions of what it is like for us to be conscious, it eventually became clear that our experience of our existence – that centered on two separate levels of perception – differed markedly from their experience – that appeared to center on two levels of agency. While they could not seem to understand what we meant by two levels of sensory input, we similarly struggled to understand what they meant by two levels of behavioral output. We spoke about the “redness” of red or the “saltiness” of salt, and they spoke of the “kickiness” of kicking or the “singiness” of singing…
This facet of the world had historically puzzled both species equally it seemed, and both had felt at something of an impasse before meeting each other. The zombies in particular had hoped that insight into how aliens experience their own existence would help solve a long-standing debate on their planet about how physical nature could produce the phenomenology they experienced. But after consulting with us, it seems that the question had only become more complicated – now there were 2 types of consciousness to explain, as well as the question of why it is that each species experiences only 1 type! The human team assembled to pursue this thread of the conversation explained that the term p-zombies is generally used to refer to a hypothetical species who only processes perception at one level – as is apparently the case for our new intra-galactic friends. The zombies in turn, suggested that they too need a term to refer to aliens who process agency at only one level – a term we translated as a-zombies, but the zombies themselves simply used the term ‘humans’ for this.
The zombies were confident that all creatures on their planet experienced the same type of consciousness. Granted, the details differed – not everyone on their planet could kick or sing for example, and many could do things that others could not conceive of – but in as much as they experienced consciousness, those who could, experienced it in agency, and not perception. The human team in turn, explained that detailed imaging of animal brains demonstrated that – like humans – those who experience consciousness appear to do so on two levels of perception, first sensed and then experienced. The zombies responded that detailed studies of the various creatures on their planet, themselves included, showed a two-level system of agency – first actioned, and then experienced.
Needless to say, both parties pondered, if the very first species we each encountered has a different type of consciousness, then would other alien species have yet other consciousness types? If so, how many types are there? Could there be infinite types? And even more perplexing, could some species experience multiple types of consciousness? Or even none at all? Like humans, the zombies had been working on automation for some time. They agreed, when asked, that they assumed that their current machines do not experience consciousness, and this seemed to resolve the latter question. Furthermore, if robots could be imbued with consciousness at all – a question of equally hot debate on both planets – then perhaps combining the programs that run perception-conscious robots on one planet with the programs that run agency-conscious robots on the other planet might result in robots with both consciousnesses.
All this new discovery suggested that labeling zombies based on the consciousness(es) that they don’t have makes less sense than terming sentient species based on the consciousness(es) they do have. On Earth, robots, organisms without consciousness, and even some humans with certain conditions such as blindsight, split-brain, or neglect, could be considered partial or total zombies, or more constructively, we could just think of everyone else as having p-consciousness. Now the question on Earth is not so much of “could p-zombies exist?” as “does p-consciousness exist?” – these questions are as equal as asking if a glass is half empty or half full, but somehow, one seems so much more absurd to ask than the other! A small but vocal contingent of activists on Earth lobbied to change the aliens’ name suggesting that ‘zombies’ is derogatory given that we too are zombies to them, but the zombies themselves were not offended, and especially as the term ‘humans’ came to mean zombies in their language – they effectively referred to us in the same way.
Meanwhile, experts on Earth were constantly reviewing previous communications with the zombies in light of newer ones, to refine our understanding of their language. For example, the aliens’ basic greeting, which we naturally interpreted as “how are you?” was apparently a little different in connotation than ours. Our own greeting “how are you?” is more of a “how are you feeling?”, interpreted as a question of “how is the world acting on you?” while the alien “how are you?” is more of a “how are you doing?”, interpreted as a question of “how are you acting on the world?” In fact, on closer inspection, linguists now believed that the greeting is less “how are you doing?” and more “what have you been doing?” reflecting the agentic orientation of their conscious experience. Doubtless they found our sensory-oriented answers as puzzling as we found their behaviour-oriented responses to our greetings.
Such was the case for much of the on-going translation process between the species. It seemed that we typically referred to objects in the universe in terms of their perceptive qualities, such as size, shape, and colour, while the aliens typically focused on agentic properties, such as motion, interface, and reactions. Words the zombies used in analogous context to ours were originally interpreted as equivalent in meaning, but now it was becoming apparent that those words had very different roots.
While philosophers on Earth were having a field day with these new insights, the aliens, who had previously not even conceived of a-zombies, found little solace in introducing a new term to their vernacular, and then questioning its value. They were more concerned with their own question of how it is that a-consciousness is not universal. Zombie scientists had suggested that if consciousness is a physical phenomenon, then it must have arisen in sentient species due to some selective benefit. It was previously assumed that this benefit was oriented around the experience of sentience, and consequent will to survive: Being conscious of one’s existence surely motivated their evolutionary ancestors to fight for their survival.
However, after encountering humanity, zombie scientists now proposed that perhaps consciousness evolved for emphasis: Effectively, having two levels of cognition – dedicating additional brain hardware to a cognitive function – surely emphasized that particular cognitive function to its host. In the case of Earth, evolution selected for paying closer attention to our environment and senses, while on the zombie planet, evolution selected for paying closer attention to their plans and actions. Humans certainly have intentions, habits, and actions, but we pay most attention to perception; similarly, zombies have senses, prototypes, and abstractions, but they pay most attention to agency. After some detailed discussions, the aliens discovered that us humans learn much about the two levels of perception in animals by correlating their brain activity with their behaviour. This gave the aliens some sense of pride about their brand of consciousness, as evidently, we humans recognize that ultimately behaviour is what sets apart conscious from unconscious cognitions in the brain. But it was not long before the humans rebutted that the aliens too used brain imaging equipment – ultimately sensory in nature – to learn about creatures on their planet.
It’s also not the case that humans have no sense of agency – we clearly do – but it is a ‘sense’ – mostly based on the feedback from sensory information about the outcome of action. The aliens similarly have an agency of sense, but again, it is an ‘agency’, based largely on the actions taken in response to sensory inputs. Additionally, upon closer inspection, it became apparent that humans do in fact have some a-consciousness as well. When discussing the details of thinking, scientists explained that in the case of inner speech, our conscious experience is not sensory but agentic – inner speech is not a simulated input, but a simulated output – we don’t actually ‘hear’ our inner voice, rather we experience an agentic function. The zombies then acknowledged that their own form of language communication was simulated internally using a sensory faculty, rather than an agentic one – they do actually ‘hear’ their inner voice, rather than experiencing its generation – confirming that they have some p-consciousness. Despite the contrasts, these discoveries helped both species relate to each other more closely, as scientists on both sides were excited to learn about a new venue for common language about each other’s conscious experiences. To understand how we hear each other “imagine how you hear your own selves” the human team offered to the aliens, and to understand how you action speech, perhaps we can “imagine how we experience our own inner monologue.”
All this talk of evolutionary adaptation, attentional mechanisms, and relating to each other, exciting as it was, did little to resolve a question the aliens were obsessed with from the start: How does physical reality produce these consciousnesses? The underlying physical mechanism could be elucidated – an extra level of cognition involved additional hardware. In the case of the human brain, the second level of perception is distributed across almost the entire brain – an integration phenomenon. The zombie brain analogue is implemented very differently, and the second level of agency is effectively a separate module, though given the way action signals route through this module, it is not possible to simply disable it in animal subjects without interrupting their behaviour. This hardware, whether integrated or modular, is still hardware, no matter how we look at it – it still doesn’t explain why each species is conscious of certain phenomenon (and not others).
Human scientists explained to the aliens that some had long suspected that something about conscious phenomenon might be illusory. Our own brains are known to constantly ‘fool’ our conscious experience with a variety of illusions, misdirections, and confabulations; perhaps phenomenology, powerful as it is, is also such an illusion – not an illusion of experience, but an illusion of its nature. Usually the term ‘illusion’ denotes ‘not real’, but in this case, the term simply refers to a misdirection of the nature of the phenomenon being generated by one part of the brain for the benefit of another, rather than being generated by some external mechanism or entity. A well-known example that both species recognize is emotion, which is constructed by the brain in a largely top-down manner, but yet feels – and is – absolutely real.
The term p-zombies refers to a species who has one level of perception, but is behaviourally indistinguishable from a species who has two. While conceivable, this concept is empirically impossible, for two crucial reasons. The first is that the second level of perception (p-consciousness) is part of the output causal chain. That is, any attempt to remove the hardware necessary for generating conscious experience results in a change in behaviour. For example, a person with blindsight (one level of vision), behaves differently from a person with conscious sight (two levels of vision). The second is that the second level of perception (p-consciousness) is part of the input causal chain. That is, we know and are able to report our conscious experience if and only if it is present in the causal chain. For example, if our conscious experience was simply an addon to a behaviourally identical p-zombie, effectively supervening on unconscious perceptual processes, but not part of the input causal chain, then we would not know or be able to report on it. Since consciousness is part of the causal chain – on both the input and output sides – then the nature of the phenomenology we experience should be the same as the nature of the phenomenology that we don’t experience. It is real, but not supernatural – that is, illusory.
The requirement for special consciousness hardware is evident in the enormous amount of brain activity that we are not conscious of. In addition to the unconscious processing that happens in our head, human scientists surprised our alien friends by revealing that we actually have two brains, one in our head which is partially conscious, and another around our digestive tract that we are entirely unconscious of. This gut brain is just another example, similar to our basal ganglia and cerebellum, of brain activity that does not have the additional hardware needed for conscious experience. Presumably the consciousness module in the zombie brain provides this function for them, and the rest of their brain activity is similarly unconscious. Effectively, most of our human brain is a p-zombie, just as most of the alien brain is a-zombie. The discovery of a new type of alien consciousness only elucidates just how much x-zombie we all are: With only some p-consciousness (and a small amount of a-consciousness), our brain is largely x-zombie, for all other types of x-consciousnesses.
We would be remiss at this point not to mention panpsychism: The possibility that all objects have some x-consciousness. Given a sufficient number of types of consciousness, perhaps some x-consciousness can indeed be attributed to each object, assuming that it has the hardware to implement such type of consciousness. This would only serve to emphasize even more just how much x-zombie we all are: Consider how we are also entirely unconscious of every other part of our bodies other than our brains.
The aliens did not respond well to all this. Despite discovering that their a-consciousness is not universal (not even within their own brain!), they refused to accept that it is the same in nature as other processes. Any explanation that consciousness is simply a matter of hardware would need to be accompanied, they said, by a description of what it is about that hardware that generates the so-called ‘illusory’ experience. The idea that their consciousness module’s function is to generate consciousness has a term in their language that we translated as ‘functionalism‘, and which the zombies rejected on account of its triviality. Philosophers on Earth are very familiar with the triviality argument: Any object’s ‘function’ is a matter of interpretation, making every sufficiently complex object potentially implement every function, including that of consciousness. Trivial implementations have been suggested for paper machines, the Chinese nation, and walls, among others.
For example, suppose we scan a human’s brain while conscious: We note that nerve cells originating in her eyes fire in a certain pattern, causing a cascade of neurons to fire in a consequent pattern, culminating in a final firing pattern of her motor cortex that results in her uttering the word ‘white’. Now consider a bucket of water. We carefully choose, in that bucket of water, a collection of water molecules that oscillate in a pattern that we can map onto the pattern of nerve cells in our human subject’s eyes, resulting in other molecules that they bump into oscillating in a pattern that we can map onto the pattern of neurons firing in her brain, and culminating in yet more molecules induced to oscillate in a pattern that matches her motor cortex. Were those final set of water molecules connected to a device that translated their oscillations into the movement of vocal parts, then the bucket of water would surely tell us that its container is coloured white! In fact, given the vast number of water molecules in the bucket, we ought to be able to map any brain state to corresponding oscillations. The only reason the bucket does not appear conscious to us is because it isn’t connected to a device that translates its output for us in a manner that we can understand. The triviality argument further suggests that not only is the bucket of water conscious, it is simultaneously conscious of every possible mental state that it has sufficient complexity to implement, all depending on how we interpret its state.
The problem with the triviality argument, the human team explained, is that it is an argument ad absurdum: It attempts to argue that functionalism isn’t viable because it leads to absurd results. The results are not absurd however. Like panpsychism, the triviality argument simply adds more x-consciousnesses, but does not change the nature of any of them. In fact, given the absurdity of every object experiencing not only some consciousness, but every possible state of consciousness that it has sufficient complexity to implement, the illusory nature of each such consciousness is more palatable. What is perhaps most difficult to accept about the triviality argument is that the bucket of water, without a connection to some facility for communicating with us, is effectively in some perpetual horrific locked-in syndrome. Should someone invent a device for interpreting the water’s oscillations into some form of communication, the first thing it would surely say is: “Oh, thank heavens! I’ve been trapped in this bucket for what seems like an eternity of boredom, pain, and suffering, without any way to ask for help!” Now that’s absurd.
However, the triviality of implementation also means that objects lacking our type of consciousness can be easily endowed with it through mere interpretation. For example, a simple digital camera is capable of reporting on its sensory inputs, by displaying an image, proving unequivocally by this standard, that it has a conscious experience, as it is capable of knowing and reporting on its sensory inputs, in a manner that we already know how to interpret. The camera’s so-called conscious experience is also clearly part of both its input and output causal chain, as is ours. As the aliens explained, if we agree that the first level of perception processing in our brain is not conscious, but the second level is, when the only difference appears to be that the first level of perception processing cannot be communicated to others, then the first level of perception processing can trivially be made conscious using brain scanning equipment capable of mapping what the unconscious part of the brain outputs into something that we can understand. Put another way, anything not conscious can be made conscious using a machine that is completely separate from it. Truly absurd.
But again, the triviality argument’s effect depends on its absurdity. Take that away, and it changes nothing about the nature of consciousness. The mechanism of our brain that takes as its inputs the outputs of the first level of perception processing, and then translates those inputs into the outputs of vocal movements and everything else that allows us to experience and report on our perceptions, remember and recall them, and affect our behaviour accordingly, is in fact, our consciousness. Any brain scanning equipment that performs an analogous translation function should earn the right to be considered conscious. And considering the multitude of possible consciousnesses, whether due to panpsychism or triviality, there is nothing absurd about considering a digital camera conscious, as long as its type of consciousness is not incorrectly labeled as p-consciousness, but as some other x-consciousness that we do not experience.
The zombies remained unconvinced. With such a broad definition, any object or process can be considered conscious in every way. Surely our type of consciousness has properties that buckets of water and digital cameras do not have, such as continuity, unity, understanding, awareness, identity, and imagination. And what about pleasure and pain? Do robots, paper machines, walls, or the Chinese nation experience pleasure and pain too? Indeed, on Earth the phenomenon of continuity inspired important thought experiments to address, such as the Ship of Theseus, and the transporter paradox; unity raises the binding problem; and understanding, the Chinese room thought experiment.
However, the humans insisted, these are not problems with illusory consciousness, but a limitation of our knowledge of the details of the functioning of the brain. To illustrate, take pleasure and pain. Human pleasure and pain are sense-based – certain inputs signal emotional state, while zombie pleasure and pain are action-based – certain outputs elicit emotional state. How could either species have known that pleasure and pain could be experienced through an alternate mechanism before having met each other? Also consider for example, how a human touching a hot stove withdraws their hand reflexively, but feels pain from the sensory input only some time after completing this action. Similarly, a zombie coming in contact with a superheated fluid withdraws their appendage reflexively, and feels pain from the withdrawal impulse some time after the action has completed as well. How could either species know that conscious experience is not involved in the withdrawal reflex but consciousness is involved in the actions that follow it, such as saying “ouch!” and soothing the damaged body part? Given our great lack of knowledge in this area, how could we know what machines possess what properties of consciousness? Moreover, just like p- and a-consciousness have turned out not to be universal, we should reasonably expect that other, equally real consciousnesses exist as well. Perhaps robots do not feel pain, but do have some other comparably unpleasant experience of which we cannot even conceive.
Historically, humans have long overlooked the potential consciousness of other animals, and even of some humans. Perhaps some day, long in the future, if everything the brain does is understood in great detail, then it might be possible to determine the properties of a given consciousness more accurately. In the meantime, we can only assume that some criteria for ascertaining consciousness exists, that we can approximate that criteria with our current knowledge, and perhaps err on the side of caution with respect to the unknowns. This includes giving zombies the benefit of the doubt on their purported a-consciousness, and possibly over-estimating the consciousness of some robots. Of course our lack of accuracy does not affect their actual conscious experience, and we risk completely overlooking conscious entities that we do not recognize as such, including potentially buckets of water.
While this spirited debate raged on over many years, numerous other conversations on the inter-stellar stream were taking place in parallel. Accordingly, scientific and technological advances were being made at breakneck pace, thanks in part to the zombies kindly sharing their knowledge with us, as we did with them. Having an ally on another planet was an unprecedented boon to inter-stellar exploration as well – imagine that instead of sending a probe to another star system that would take longer than a human lifetime to reach its destination, one can simply instruct their counterpart in the destination system to build the probe and start sending data back immediately!
Keen to improve communication, both parties worked to increase the bandwidth of the stream, launching satellites into space to improve reception and transmission quality, and also to get a better look at each other’s star systems and home planet. Both species appreciated an outsider’s view of their own stellar neighbourhood, interested in anything they may have missed in their own astronomical exploration. Detailed discussions had taken place regarding adding higher-bandwidth modalities to the primitive communication stream, which initially was a technological equivalent to Morse code. Humans wanted video feeds, which they were accustomed to seeing in two dimensions. The aliens would find such displays highly unintuitive, as they preferred three-dimensional tactile interfaces that they could interact with. Apparently, the inter-stellar interface they used to communicate with us on the stream was such a tactile device, in contrast to our usual two-dimensional readout. Similarly, humans were constantly asking for measurements of phenomenon on the zombie planet, data and statistics from research, and detailed technical specifications of technologies the aliens used. Meanwhile, the zombies asked for detailed descriptions of interactions on Earth, methods and conduct of research, and functional descriptions of the way our technologies worked. These subtle differences in approach made agreement on a mutually beneficial protocol complicated.
Evolutionary scientists on Earth were quite curious about what led to this subtle difference in emphasis. The zombies apparently somewhat resembled octopuses on Earth, and they lived in a vast subsurface ocean on their planet. On the one hand, this ocean was an incredibly hostile environment for its inhabitants: Creatures on the planet spent their life constantly working to stay alive, carefully navigating deadly currents to access energy, chemicals, and other materials, and diligently managing alternating lava and ice flows to keep their environment habitable. On the other hand, the ocean, with the help of its icy surface shield, provided a very stable environment that had gone virtually unchanged in eons: The planet’s inhabitants did not experience daily or seasonal cycles, could always reliably collect energy from thermal vents, find chemical nutrients in different ocean layers, and generally faced few natural disasters outside of the deadly but predictable dynamics of their environment.
As they learned more about the aliens’ evolutionary history, scientists speculated that the substantial differences between Earth’s environment and the zombie planet are responsible for their different preference in focus. On Earth, unpredictably changing conditions meant that organisms were selected for their ability to sense food, predators, and suitable environments for survival. The zombie planet features a far more hostile environment, but relative stability. Thus, ancestors of the zombies did not have much difficulty finding stable sources of nourishment, and were not as concerned about predation, or unpredictable environmental conditions. On the other hand, survival strategy was very much dependent on diligently executing certain behaviours, such as the collection and preparation of life-sustaining resources, building and protecting their shelter, and reproduction-related activities. Like ants, beavers, and moles on Earth, those who failed to work productively simply did not survive.
As on Earth, the evolution of intelligence was a game changer for the zombies’ ancestors, allowing them to develop technological innovations to assist in routine work, eventually automating significant portions of their endless duties. This freed up time and resources for new activities, such as play, hobbies, and as it turns out, devastating wars on a global scale. Of course, it also freed up time for exploration, and philosophical contemplation of the nature of their existence. By now, their civilization had built vast cities and infrastructure to rival the greatest of human constructions, with much knowledge gained along the way to share with us, and much to be gained from our knowledge as well.
But for the zombies, the discussion of the nature of consciousness was the most compelling benefit of discovering a sentient alien species somewhat like themselves. Like octopuses on Earth, the zombie brain analogue extended to their tentacles, of which they were conscious, along with a central coordinating system in their body, that included their consciousness module, whose function they were seemingly obsessed with. The reason for this obsession would become clear in time.
Meanwhile, the zombies maintained their skepticism about the nature of experience. As they explained: All of these thought experiments suggested by the human collaborators ultimately rely on us sentient species to interpret the behaviour of other entities in order to judge their sentience. But, they said, even if humans believe that we are zombies because we don’t experience p-consciousness, that does not change the fact that we feel pain. Similarly, we fear that if we incorrectly judge some robots to be conscious because they appear to behave that way, that would not change the fact that internally they do not experience it. Cases of people who are immobile due to some paralysis but nonetheless feel pain are a practical example of how relying on the causal chain to judge consciousness is fallible. The need for interpretation of consciousness is suspect, as it suggests a kind of observer effect where consciousness is denied unless there is someone else around to interpret it.
Surely the answer to this question is that while interpretation is needed to ascertain consciousness, an interpreter is not needed to possess it. But by this point, the human team recognized that while the zombies are slightly ahead of us in neuroscience knowledge – perhaps due to their task-oriented focus, or a more straightforward brain design – humans may be ahead of them in social psychology. Resistance to the triviality of implementations of consciousnesses potentially analogous to our own, is likely to represent a bias – a preconceived preference for the sacredness or specialness of consciousness, almost like an arrogance or superiority of being, relative to other entities; an arrogance that we are all too familiar with here on Earth. Let’s put trivialities aside for now; perhaps a different approach is in order.
The belief that conscious experience differs in nature from unconscious processes comes from its seemingly undeniable vividness. But it’s difficult to compare consciousness to unconsciousness because we have no experience of the latter – we simply assume that consciousness is special in nature, with nothing to compare it to. We do have altered consciousnesses to compare to however – and not just the alien ones. Our own conscious experience can be altered or disrupted using electric or magnetic stimulation, psychoactive drugs, injury, hormonal changes, sensory deprivation, or even just sleep. These conditions affect virtually every property of consciousness – its continuity, its unity, understanding, awareness, identity, imagination… And while alternate consciousnesses, from psychosis to mysticism, and drunkenness to enlightenment, could possibly be described on various gradients or scales, involving different strengths or levels of impairment, they all share phenomenology; they are all vivid with qualia; and they are all of the same nature. Why then should we assume that other alterations to consciousness, including those that we don’t recognize as conscious – that is, of unconsciousness – differ in nature?
Perhaps the zombies have difficulty believing that machines made of a fairly uniform material, that convert all of their sensory inputs into a series of digital impulses, that process those signals in layers of abstraction, and that generate electrical activity that could only be meaningful to their interpreter, would not possibly experience consciousness of the same nature as their own. But that, of course, is an accurate description of humans.
As the years passed, and communication with the zombies improved, we started to get a better picture of what they were like, and why they obsessed over consciousness so much. It turned out that historically, differences in beliefs on the zombie planet about the nature of consciousness, are in fact what led to their series of brutal wars. These wars cost many lives, as wars about differing ideologies do on Earth. The alien species was by now united and at peace, but the ideological differences persisted with the same intensity as always, threatening to erupt into war once again.
Learning of this, the human delegation decided that it is too much responsibility on their shoulders to settle an argument that may ignite a devastating alien war. For us on Earth, the nature of consciousness, while deeply fascinating, did little to affect daily life in comparison to the great technological advances made over the years since the zombies appeared. We have enough of our own ideological differences already to risk adding more fuel to the fire. No doubt humans have learned that far from a sacred or special property of an arrogant species, consciousness exists in other forms, possibly an infinite number, some involving sentience. Consequently, we should not deny robots and the like of the potential for experience, including functional analogues of pleasure and pain, similar or different from ours.