I think there is a consensus that among all the beautiful artefacts of Nature, the sunset stands out to be the most majestic in its way. Of course, it is one of its kind as there is only one Earth and one Sun in the solar system we reside in, hence as a consequence, it becomes unique. That red hue rich with a blend of purple and crimson painted in the sky, as that ball of fire sinks slowly but gently under the horizon, creating a majestic work of art!

It is a very perplexing scenario, as such subjective experiences are our own, and we can actually “feel” the beauty of such scenery. Although in terms of objective reality, it does not possess any such values. The giant ball of hot plasma reaches a soaring 5500 degrees centigrade at its surface. It emits electromagnetic radiations which travel 150 million kilometers in the vacuum to reach a planet roughly one-hundredth the diameter of the Sun. The electromagnetic radiations in the visible range of the spectrum scatter specific wavelengths while interacting with the atmosphere of Earth. The scattered waves are subsequently received by the sentient primates residing on the surface of this planet, where these animals perceive the information with their visual cortex, and as a consequence of this whole process, they “see” the sunset.

Albeit, what’s most confusing about the entire process stated above is that there is no room, or rather no intrinsic necessity for “beauty” associated with the sunset. Yet some of the primates like us – Homo Sapiens – who are sentient beings, perceive the beauty in Nature. We have this first-person experience, where we assign such subjective values and attributes to the physical world, which is in the most real sense, existent only in the eyes of the beholder.

This is the puzzle of conscious experience which philosophers and scientists have been analysing, debating, and trying to define for centuries. The subjective experience of such sentient beings, where they are “aware” of the internal and the external existence, is precisely the perplexing problem of consciousness.

Consciousness is probably the most familiar, yet the most mysterious phenomenon we experience. We are aware of the physical world we see around us, and we assign subjective attributes to the external physical world. Yet, the emotions we experience are fundamentally qualitative in Nature. We are aware of it, yet there is no possible way to quantify feelings and subjective experiences. This makes the problem of consciousness extraordinarily complicated and challenging to understand.

Neuroscientists and philosophers in the last century have been struggling to reach a common ground to formulate the problem of consciousness in a compliant manner and approach the solution using the scientific method – which in itself is objective and disregards conscious experiences from physical phenomena.

In a 1995 paper by the philosopher David Chalmers titled “Facing Up The Problem Of Consciousness”, the problem of consciousness was subdivided adequately into two categories, the “easy problem”, and the “hard problem”. David Chalmers clarified that the “easy problem” is in no way easy, rather it is easy in relative terms as compared to the “hard problem of consciousness”. The “easy problem of consciousness” is a set of questions which might end up requiring centuries worth of empirical work, but are rather relatively easy as they are amenable to the scientific method of investigation. The easy problem of consciousness as characterized by David Chalmers is the problem of understanding the neuro-biological explanation to:

• The ability to react to the external environment
• The integration of the information by the cognitive system
• The ability of the neurological system to access its internal states
• The focus of attention
• The difference between wakefulness and sleep
• The deliberate control of behaviour

And so on. These are the processes occurring in our brain, which can be explained by understanding the neural synapses and the functioning of the neurons as a single unit and as an aggregate. The hard problem of consciousness as categorized by David Chalmers is:

• Understanding why there is awareness of the external and the internal world associated with the sensory information we receive from our five senses
• Why is It that only some organisms have subjective experiences?
• Why is there a subjective component to the external stimuli?
• Why don’t philosophical zombies exist in our physical world?

Before moving any further, it is essential to address one crucial concept which is central to the hard problem of consciousness: the existence of philosophical zombies.

A philosophical zombie (p-zombie) is a thought experiment which posits the existence of beings that are physiologically indistinguishable from Home Sapiens, but they lack the first-person conscious experience. They have the same brain functions like a sentient human, and they possess all the same neurological processes and the cognitive system as described by the easy problem of consciousness.

Such philosophical zombies show a reaction to stimuli, and they can integrate information by their cognitive system, and “behave” exactly like a conscious human. If one inflicts pain to such a being, they would display the pain exactly like a sentient human, but would lack the inward conscious “feeling” of pain.

The very definition of a philosophical zombie posits the most bewildering aspect of such beings. If one asks the p-zombie the very question of whether they possess any conscious experiences or not, their response will be identical to that of a sentient human – their answer will be yes!

In our physical world, we know about the non-existence of philosophical zombies, or at least we can assume it to be true. The argument of their existence or non-existence is intertwined in a very intricate manner, which makes this thought experiment very formidable. There is no way for me to be sure that the conscious humans I interact with, or even you who is reading this article at the moment, are a sentient human or a p-zombie.

The only known existence of conscious experience in this world is that of mine. Although I cannot be sure about others, I know about the real presence of my conscious experience; I can feel the blueness of the sky, the beauty of a melody, and so forth. This exact argument also applies to you. You cannot be sure of my claim of being a sentient human, as my claim is indistinguishable from something a p-zombie would say. The only thing you can sure be absolutely sure of is your consciousness, and that is the most you can logically achieve in terms of surety.

Of course, the very argument of p-zombies is to establish the distinction between the easy and the hard problem of consciousness. The case of a p-zombie is actually in favour of the mind-body dualism, as the logical existence of a p-zombie would discard the other schools of thought under the main category of physicalism, namely materialism, functionalism, and so on.

There have been rebuttals to this kind of formulation of the problem of consciousness, as there are some who believe that in the pursuit to solve the easy problems of consciousness, the very property of conscious experience would emerge from such processes. However, they don’t completely address the “why” of the hard problem.

There have been magnificent efforts made by some of the leading neuroscientists working in this field to investigate even deeper into the problem of consciousness from a neuro-biological point of view. Molecular biologist Francis Crick and neuroscientist Christof Koch have made significant progress towards identifying the processes in the brain which correlate to the subjective experiences. These events are called Neural Correlates to Consciousness (NCCs), and it is hoped that such events, although categorized under the easy problem of consciousness, might show us the path towards understanding the emergence of subjective experiences.

Although these scientists, and many others, have been working hard to find a correlation between the inner workings of the brain and the subjective experiences, they agree that the hard problem of consciousness may still be intractable even if we have a full understanding of the NCCs.

There is an analogy explaining the hard problem of consciousness proposed by Christof Koch, which resonates with me, and I have been thinking about it quite a lot. It is stated as follows:

Suppose we write down the equations of gravity as formulated by Einstein’s general theory of relativity, and supply all the necessary numerical values of mass and all the other constants to simulate the gravitational effects of the Sun. We feed the equations to a supercomputer along with all the associated numerical values and constants, and after solving the equations, the supercomputer gives us the output of the resultant gravitational field produced by an object which is about the mass of the Sun. There is, of course, a high degree of accuracy in the results, and we can verify the solution by using the same equations to measure the gravitational effect of the Sun on the Earth by its motion around the Sun. So, in a nutshell, we just simulated the gravitational forces of the Sun on a supercomputer with a high degree of accuracy! But why didn’t we get sucked into the supercomputer? After all, it produced the exact values of the gravitational field as that produced by the Sun itself!

Well, the main disparity between these two scenarios is the actual “substrate” on which the exact same information is getting processed. In case of the Sun, the mass of the Sun is warping the spacetime around it, and hence the effect of gravity is produced; and the numerical value of that gravitational field can be measured by us.

But in the case of calculating the value of the gravitational field with the help of a supercomputer, although we are dealing with the exact same information, but the data is being processed in terms of 1’s and 0’s in the CPUs of the supercomputer. Hence, that information is not acting upon the necessary “substrate” to yield the “physical” effects of gravity.

Christof Koch argues that this might be the case with consciousness as well. He thinks even if we figure out movement of every electrical signal passing through the neurons in the brain, and simulate the entire neural network of the brain on a computer, still, that computer won’t be “conscious”. There is a requirement for a unique substrate on which the information has to act upon, and the processes have to occur on that substrate for consciousness to emerge. This is precisely the hard problem of consciousness.

A similar argument was put forth by mathematician Sir Roger Penrose, who thinks that consciousness is non-computable, and may not be explained by the laws of classical physics. He believes that consciousness arises from the quantum mechanical effects occurring in our brain. This might be a tangible prospect as to the reasons of why there are any subjective experiences associated with the processing of information by the cognitive system.

Whatever may be the answer to the hard problem of consciousness, or whether there is even a logical possibility of a solution or not, one thing for sure is that, consciousness in itself is more mysterious than anything a conscious being like you and I can possibly imagine. It is so complicated that as a consequence sentient beings spend a lot of time thinking about it! I am grateful that this universe allows for such phenomena of consciousness, as otherwise, I won’t be writing this article, and you wouldn’t be reading it…

FURTHER READING:

• Consciousness
• Hard Problem of Consciousness
• Philosophical zombie