Saturday, August 29, 2015

The mind-body problem and the hard problem of consciousness explained

Abstract: In this essay I try to reconcile the two available sources of information about consciousness. One source is science, which gives us insights into how brains work. Another source is introspection and opinions expressed by other people talking about their subjective experience. The hard problem of consciousness can be understood as inconsistency of the information provided by these two sources. I propose a reductionist theory based in evolutionary psychology that accounts for subjective experience and explains why introspection yields thoughts that are seemingly incompatible with fully reductionist point of view. By incorporating thoughts of individuals and their opinions about nature of consciousness into the reductionist theory, I reduce the set of unexplained or inconsistent observations, on which the hard problem of consciousness is based, to null. Given there is no more unexplained observations left, regardless of whether they are objective or subjective, the hard problem of consciousness appears to be solved. 


People are baffled by the notion of consciousness. There have been many theories of why the consciousness arises and none of them seems to be satisfying. Dualism (e.g.mind is immaterial and somehow communicates with brain) is just a pure speculation which offers no explanation in a scientific sense. Other theories, like panpsychism (every single molecule has consciousness but the more complicated the system, the more consciousness it has), are not falsifiable and offer no predictive power. Finally, full reductionism (mind is a product of a physical brain) fails to address the reason why we are able to distinguish between subjective experience and objective world.

People discuss consciousness, mind-body problem, and the existence of qualia – the discussion itself is an objective fact about reality. Electrical and chemical impulses originating in their brains make the muscles in their mouths and throats contract so that the corresponding statements are uttered. It is thus an objective fact about reality that there is something in the brains of these people that causes them to perceive consciousness or qualia as something that cannot be explained by material science. What are the origins of these electrochemical signals? Is there some mysterious soul that through yet unidentified physical mechanism facilitates transfer of information between the realm of spiritual and the realm of material? Or the mental properties of elementary particles in a brain unite in some mysterious way to influence the neurons responsible for perception of consciousness? Finally, maybe there is a fully reductionist explanation of why these neurons get activated and why our brains produce behavioral outcomes like the writings of Rene Descartes?

It is bizarre. The best model of the Universe that science has been able to come up so far, the model that is being constantly positively verified, yields good predictions, and helps us solve practical problems, is materialistic and reductionist. All objective evidence points to the fact that a mind is a product of a brain and nothing else. Brain has not been fully understood yet. Mind has not been fully understood either. So maybe understanding the brain will let us understand the mind? It is bizarre that philosophers are often so quick to reject a notion that once we fully understand physical brain we will fully understand human experience. Why is that?

A solution

To sketch a quick explanation, let me first focus the attention on what the problem is. When you think about other humans as humans, or when you think about your own thoughts, there is something you perceive (the common notion of consciousness). But you no longer perceive this thing when you think about the brain tissue, firing neurons, electrical circuits of a robot, and such. The perception of it, when you think about humans as a whole, and failure to perceive it, when you think about them in a reductionist way (biological tissue), is what causes the dissonance in your brain. Your brain perceives this dissonance and makes your mouth utter the statement like: ‘The really hard problem of consciousness is the problem of experience. When we think and perceive there is a whir ofinformation processing, but there is also a subjective aspect.’ The notion of “information processing” (reductionist part) does not cause the feeling that you have about yourself when you ponder the phenomenon of your own thought. This is why a thought must be something more. This is what the problem was during the time of Descartes and this is what the problem still is as discussed by modern philosophers talking about the hard problem of consciousness and the existence of qualia.

To solve the hard problem of consciousness we need to explain why people perceive consciousness in some things and they do not perceive it on other things. The answer lies in evolutionary psychology. Every healthy human being has a system in their brain that is supposed to detect minds. This system is activated when we think about sentient beings but is not activated when we think about meat or a piece of silicon. The reason why we have this system is to facilitate our socials interactions. We need to recognize other humans so that we can feel sympathy or compassion, and help them when they are hurt while not having the same feelings towards a broken cardboard box.

Evolutionary psychology explains

A human brain has a number of systems that allow for recognition of objects that are important from the evolutionary point of view. Recognition of such salient objects usually facilitates specific behavior which is a response increasing genes’ probability of survival. When you see a naked body of a potential sexual partner you are inclined to get closer. When you see (or smell) a rotting carcass of a rat, you are inclined to move away. When you see a baby, you feel a need to care about it. And so on.

The perception of a salient object often generates a feeling. This feeling can be overcome under some circumstances. It cannot be treated as a sole determination of human behavior, it is just guidance. There are other factors that can be more important (e.g. there is a lion between me and the naked body of my lover). But the important fact is that detection of salient objects happens outside of our thoughts – we cannot chose to be attracted by a carcass instead of being repelled. We can at most ignore the feeling of repulsion.

Another important fact is that systems for recognition of salient objects are very crude and prone to mistakes. It is probably very hard to precisely shape the structure of a brain by genes. There is an engineering tradeoff involved – our brains are not designed to be perfect. They are designed to do their job in most situations at a moderate cost.

One of the examples of such crudeness is recognition of a sexual partner. It is very common both for humans and in the rest of animal kingdom to get aroused by things that are far from actual potential sexual partners. It is easy to find on the Internet a picture of a tortoise having sex with a stone or a dog humping his owner’s leg. It is also very easy to find a lot of pornography. Pornography allows humans to get aroused by a pattern of colorful dots rather than by the presence of an actual sexual partner.

Similar phenomena occur with respect to perceived cuteness. It is quite simple to discern what facial features activate a mental system that was most likely intended for the recognition of human infants (cartoonists know it too well). Seeing something with big eyes and a little nose mounted on a big head makes us feel like we need to care about it. But it is not only infants that have these features. Most of young mammals have them which is why we perceive kittens and puppies as cute. From the evolutionary point of view, this may be a mistake – we are misidentifying a salient object and misallocating our resources (as we waste time on caring for a puppy instead of a member of our own species, say a relative). But it is not easy to determine whether this phenomenon is really a bug or a feature – there is not only an engineering tradeoff involved in making the recognition mechanism crude. There may be also some yet-to-be-discovered benefits from making such “mistakes.”

The mind as a salient object

The toolbox our brains are equipped with contains a lot of systems that guide our behavior when we interact with other humans. For example, there is a subsystem responsible for basic moral behavior. It takes a great deal of emotional effort to kill somebody you consider to be a fellow human being. There is a feeling of compassion you feel towards somebody in need. There are feelings of unfairness that we have when others do not reciprocate. And so on. All these emotional responses are culturally universal and have simple evolutionary explanations.

Is there any other evidence that such subsystem exists? Let us consider genocide. Something that happens very often before genocide is a process of dehumanization of a group that will be subject to extermination. In the brains of perpetrators, dehumanization effectively disconnects the system for recognition of fellow human beings from the input generated by the victimized group. You no longer perceive victims as humans – you now perceive them as cockroaches or rats, which does not activate your moral intuition and makes them worthy of extermination.

When you watch debates or read articles about consciousness, you may notice that people often intuitively make a connection between consciousness and moral behavior. And it is not only vegetarians that refuse to eat “sentient beings.” People who otherwise eat meat, sometimes say that since octopi, elephants, dolphins, and monkeys were identified as self-aware (they can recognize themselves in a mirror), it is thus immoral to eat them. The questions what is conscious and what is not conscious is important precisely because conscious beings seem to require moral treatment while beings that are not conscious are just things that can be dealt with without as much respect. Note that lack of consciousness at the time of committing a crime is often a condition for more lenient verdict.

Like other systems for recognition of salient objects, the system for recognizing minds (or consciousness / sentience / souls / feelings / subjective experience) is not perfect. It can be overridden (as we saw in the example of genocide) and it can be activated by the stimuli it was not likely intended for. Such a misidentification can yield a decision that results in misallocation of resources and could be detrimental not only from the evolutionary point of view but even from the viewpoint of subjective wellbeing of the individual.

There are a lot of examples showing the system for recognizing minds being activated by a mistake, when there is no actual human mind present. As I already mentioned, it is often activated by animals, which leads people to refuse to eat them and chastise those who do. It is activated by fetuses, which leads people to strongly oppose abortion and demonize those who do not. It is activated by inanimate objects and natural occurrences in people who believe in spirits and worship gods (and trade favors with them by making offerings, including human sacrifice). And finally, some people make a connection between this system and the entire Universe, which leads to panpsychism.

The existence of such a system can be potentially empirically verified. It implies that there is a pattern of neurological activity that occurs when a human detects a mind. There is also a pattern corresponding to at least some moral judgements which is then tied to identifying the subject of a judgement as a mind.

What is consciousness?

The main point of this essay is that there is no evidence, whether subjective or objective, that leads to a conclusion that mind is something more than a product of material brain, given the laws of physics as we know them. All the subjective “evidence” against reductionism can be explained by reductionism and there are no arguments left in favor of other theories.

Reductionism explains such “evidence” by showing that it is created as a result of cognitive dissonance caused by the system for detecting minds which gets activated while thinking about humans holistically or performing introspection, and is not activated while thinking about nerve tissue. The hard problem of consciousness has thus no origins in reality but is a product of inadequate perception abilities of the human brain. In other words, the question is not whether the thing exists but why do we have an illusion that it does. Similarly, when you are visiting a psychiatric ward, you do not find yourself concerned whether one of the patients really is Napoleon Bonaparte. You are more likely to analyze WHY he thinks so. The thought that all healthy humans have some mental deficits leading to delusions might seem depressing but on the other hand we cannot just start off with an assumption that we are perfect.

Having addressed the main point of this essay, an interesting follow-up question arises: does consciousness even exist? Before discussing existence one must have a good definition of the thing in question. A good definition identifies a phenomenon by its properties and enables us to objectively discern whether a phenomenon satisfies the properties or not. In other words, a good definition should let us objectively determine whether something is conscious or not. A good definition should be also as close to the common use of the word as possible. Most of the available definitions describe consciousness by vague associations with notions like sentience, awareness, subjectivity, or ability to feel and fail at satisfying these criteria.

The word “consciousness” is commonly used to describe phenomena which activate the mind detection system in a brain of the person who speaks about it. Unfortunately, for different people, different objects activate this system which causes a lot of confusion. Despite trying hard I was unable to come up with a reductionist definition that would be based on this approach. Hence, a different approach is needed.

Another common way of talking about consciousness is when we contrast conscious mental processes with unconscious mental processes. The former are what we can speak about after investigating our own minds trough introspections and the latter seem to be “given” to us in form of feelings or information, for example who the faces belong to and whether they are attractive.

Hence, I espouse the following definition of consciousness: “Human consciousness is a collection of mental processes that can be remembered and talked about later on by a healthy human being.” This particular definition seems to be useful as it allows empirically verifying what the content of human consciousness is and what it is not. It relates to what we care about – the experience we can share with each other, the experience perceived as the content of the Cartesian theater. It is what the mind detection system is most likely supposed to detect. Finally, its similar version has been already used by reputable scientists.

What about animals then? Do they have consciousness? Well, it depends on what scientific question we are asking. We are surely not interested in knowing if animals possess the imaginary and emotionally loaded quality whose illusion is caused by a failure of the mind detection system in our brains. We know that animals are aware (that is they have a working model of the environment in their brains) and often self-aware (that is they have a working model of their bodies and maybe even their own thoughts). But we don’t have to give these phenomena a new name. Word “consciousness” seems to be interesting from the perspective of humans willing to investigate what they are able to communicate about, but it does not have any obvious application in case of other animals, since they cannot speak.

Let us now think about a philosophical zombie, a creature imagined by philosophers, a creature that behaves exactly like a human but does not have subjective experience – a very sophisticated robot. Consciousness does not exist in a sense that there is something mysterious that differentiates a philosophical zombie from a human being. As a matter of fact, the notion of a philosophical zombie was engineered as a human being who does not activate the mind-recognition system. The difference between a human and a philosophical zombie is in subjective perception, not in the objective properties of the objects being studied.

Subjective experience

Finally, let me address the notions of subjective experience and qualia which seem so real and yet reductionism seems to deny their existence. Do I claim that they do not exist? On the contrary. Subjective experience exists and manifests itself as and only as a state of a brain. Subjective experience is a pattern of neural activity. Qualia correspond to various states of physical brain. Knowing perfectly configuration of a brain is enough to fully understand human experience and to predict with highest possible accuracy (subject to quantum uncertainties) how a person is going to react to a particular experience.

The current state of neuroscience does not allow modeling precisely the neural machinery that gives rise to our thoughts. I can only speculate that, for example, there may be a pattern of neural activity that gets activated when you see red color. There also may be a pattern that gets activated when you want to say what you see. Neurons in the part of the brain responsible for speech detect that these two patterns have been activated and they send a signal to your mouth. You say ‘I see red.’

There may be a pattern that gets activated when you perceive a mind. It gets activated when you think about your own perception of red color. But it does not get activated when you think about your own brain tissue. The patterns associated with these two phenomena get activated due to different inputs and cannot be merged. Failure to merge them is recognized and a pattern corresponding to detection of cognitive dissonance emerges. This pattern in turn makes your mouth say: ‘My subjective experience cannot be explained by reductionism.’

Note: Special thanks to Kamil Faber and Julia Madajczak for helping me make this essay slightly less unintelligible.