10.2 The Hard Problem of Consciousness
Anyone who has dabbled in the field of philosophy would have definitely come across “The Hard Problem of Consciousness”. It is a controversial topic. There are many people who don’t admit that there is a hard problem here at all. I beg to differ.
Before we get into the hard problem, let’s first work out what Consciousness is. I have been using the term “mind” so far as I was just too lazy to type “consciousness”. We will use the both interchangeably. What does a mind constitute?
Experience - Both that of the external world and the Internal world.
Thinking
Intentionality - Will to do things
Can a physicalist system explain all these phenomena in terms of physical processes?
Thinking
A physicalist could explain away thinking by saying that modern day computers, using machine learning, are capable of following the same thought process as humans. There are still open questions about whether a machine is as capable as a human, when it comes to rational and even creative thinking. But the gap is reducing fast with AI.
Intentionality
This is the expression of will. As opposed to a rolling ball which feels to us like just going through its motion in a physical world, following the laws of physics, we feel a sense of intentionality within ourselves and the other humans and even many animals. It is one of the signs that we use to decide if a being is conscious. Modern development in robotics means one can build a robot which looks as intentional as robots. So maybe this gap is reducing fast too?
Experience
This is where the most controversial and the hardest challenges for physicalism’s explanation for Mind comes from. “Experience” here means both experience of the external world, like colour, shape, smell, sound, touch and internal experiences like thoughts, joy,anger, a sense of self and so on. Explaining all these in a coherent way has to cross a lot of obstacles. We will go through them one by one.
Qualia
Philosophers often use the word qualia to describe our sensory experience. What is qualia? Look around you. You see objects, maybe some people, maybe a garden outside of your window and so on. You sense your environment in terms of shape, colour, sound, smell and even temperature and so on.
How does science explain how we sense these? Is colour, for example, a property of matter in itself or a property of how we sense it? How does science explain colour? When light waves hit an object, the object absorbs a part of the light and reflects the remaining part(depending on the wavelength of the light). This light wave of a given wave length reaches our eyes which react to this light. The cones and the nerves in the eyes react differently to different colours. Thus, the eye translates the light signals to different nervous signals which eventually reach the brain.
And then…. BAMMMM! You get a visual experience of the object in its colour. This experience is what they call qualia. How are the signals in the brain translated to this visual experience? Depending on the wavelength of the light, the signals which reach the brain are different and give rise to our different experience/qualia of different colours. How does all this happen?
Philosophers question this because none of the phenomena we observe directly and are explained by science covers this. We see objects moving. We see objects experiencing different types of forces. But we never see the signals reaching the neurons in the brain translating into qualitative experience. We experience it directly. But we cannot see how this works. When we look at others, we can categorically say that the light waves from a bulb reaches their eyes and then their brains, but we never get to actually see them experiencing the light. You don’t have direct access to their visual experience of the scene.
This leads to the problem of inverted qualia. What if the blue colour you see throughout your life is seen as yellow by your friend? When you look at the bluebells, both of you call it blue. But within your friend’s mind, the colour of the bluebell looks exactly the same as how a yellow coloured flower looks to you. Because this has been the case ever since your friend was born, he calls it blue colour even though his sensory experience of the blue colour is same as the sensory experience of your yellow colour and vice versa. You have no way to know if this is the case.
Within the hard problem of consciousness, I think this is the hardest problem. How does the physical state of the brain cells turn into this beautiful experience we are having? Scientific experiments could give us a clue about which part of the brain has to be triggered in what pattern so that we could experience a specific colour. But how the brain state translates to qualia is not solved yet.
Physicalists claim that it will be solved eventually. Others argue that it cannot be for various reasons, the biggest one being the private nature of mind.
The Private Mind
The world would be a simple and at the same time boring place if we all could read each other’s mind. The mystery is what makes navigating the world difficult and at the same time interesting. Just take the case of a romantic relationship. Will asking someone out, first date, proposal, etc. be as exciting if you can just read their minds and see what they are going to do?
Some philosophers argue that the mind is not necessarily private as you can read someone’s mind through their actions most times. Your chatterbox friend is suddenly silent for a long time? You know they are worried about something. There is an element of truth to it. But one would be lying if they haven’t come across any human in their lives with a permanent poker face who is hard to understand. And then, there are cats. We could make judgments based on actions. But as things stand, it is impossible to get access to other people’s minds.
Getting back to the problem of physicalism, how does the private nature of mind affect physicalism? It throws a challenge to the scientific method itself, not just physicalism. Remember the rule that any law added to the system must make observable predictions and be falsifiable.
Can any law about how the mind works make observable predictions? If you are verifying the law of gravity by dropping a ball from a building, everyone can observe the results and agree that the law works. But what about a theory of mind that says if the brain cells in a region are in an L shape, you will see a zebra in your mind? Let’s say that we have managed to build an experimental set-up where someone is awake while we have drilled into their skull and are working with their brain cells. Horror movie material, I know. We then set the L shape in the appropriate region. The test subject says that they see a Zebra. Is that a successful test?
What we have now is a report of what a person observed. It is not a direct observation of the result. This is where the controversy lies. Can you trust this as observational evidence? Does it still fit within the scientific requirement of observational evidence? Maybe you will see this as a valid experimental result if you are the test subject. But will you trust the results from the others? I hope you see the challenge here compared to a traditional scientific experiment.
The Sense of Self
We all have a sense of self that feels indivisible and immutable. Our character and thinking changes but we constantly have a sense of self that seems to experience the world. There is a question of whether the self itself is a part of the experience or is it the self that experiences the world. Is the self a part of the mind or is the mind the self? Either way, physicalism has a challenge explaining the sense of self because everything physical seems to be divisible and mutable. Even if we assume that the particles in the standard particle model are indivisible, physicalism explains our mind using the brain which has a lot more particles than just one.
Most physicist theories of mind just admit that your brain just changes a lot over your lifetime and hence a unique identity for yourself across time is indeed an illusion, which is a fair argument.
Unitary experience
The mental experience also feels like a single unitary experience. How did such a complex brain end up creating a single unit experience? You have numerous sensory signals coming from your eyes, ears, nose, tongue and body and somehow the brain puts them all together and gives you a unitary experience. Can this be physically broken? Can the brain suddenly split into multiple conscious experiences at the same time? There are some obscure cases where claims have been made that it indeed happens. But nothing that categorically proves this is the case. This is another thing that science is yet to explain.
When did consciousness develop?
We de facto assume that humans have consciousness. That was one of the two primary assumptions we made when we built the layman’s philosophical system. We also admit that many big animals like dogs, cats, lions, etc. have consciousness. But we don’t admit that bacteria have consciousness. Where in the evolutionary chain between the unicellular organisms and the humans did consciousness develop?
Some physicalists explain it by saying that consciousness is not binary and there are levels to it. What level an organism is in depends on the physical properties of the brain. Again, a fair explanation, but yet to be proven.
There are also questions around the evolutionary advantages of qualia. Take a humanoid that has a brain like us except for the parts which generate the qualia. It still has the ability to think and act intentionally just like a human. It can still be as good at survival as humans. Why did evolution add qualia to living organisms if we can survive the same even without it?
Subjective vs Objective
Beauty lies in the eye of the beholder
Art is subjective
Your mileage may vary
We often use lines like these to say that many things in this world are subjective. An art that is beautiful for one person looks not so great to another. And yet, when it comes to qualia, our default intuition is that they look the same to everyone.
On one hand, when we think about qualia, we assume that all of us sense things the same way and we all have the same qualitative experience which is deemed to be objective. But when it comes to our response to this sensory experience, the second order effects like feeling something is beautiful, we tend to assume that it is subjective though it is the same brain that senses the art and determines if it is beautiful or not. Why is that? Where do we draw the line between objective experience that is the same for everyone and subjective experience which is different for different people?
Explanations
As mentioned before, we don’t have a single agreed answer to the explanation of mind in the physicalist framework. They all agree that the brain and a bit of the nervous system is responsible for our mental experience. But there is no single agreed upon theory. There are quite a few physicalist theories about how the mental experience arises from the brain:
The brain state is identical to the mental state
The conscious experience is a property of the brain
The conscious experience is the effect of the brain in a state which is the cause
The conscious experience is the result of functional processes in the brain, just like a computer that keeps giving output by processing input
Eliminativism claims that mental experience is an illusion and it doesn’t exist at all. Though I promised not to take sides with any philosophy, this is a bit too much, even for me. Maybe the eliminativists don’t have a mental experience and are just philosophical zombies. But I do have it.
The physicalist theories mentioned above have their own gaps which critics question. The usual physicalist answer is that we will find answers to these questions with time. It is up to you to decide if the weaknesses in the physicalist explanation of mind are insurmountable or not.
Book recommendations
Philosophy of Mind: A Comprehensive Introduction by William Jaworski
On Mind and Matter by Erwin Schrödinger
I am a Strange Loop by Douglas Hofstadter
Consciousness Explained by Daniel Dennett