Consciousness

What is Consciousness?

I perceive a world, whether objective or subjective (see Existence). What's more, I am aware of the world. I am also aware of myself as a part of that world and of my thoughts. These things make up my consciousness.

Defining consciousness any more rigorously than that isn't possible, though it is often described as subjective experience, thoughts, experience, knowing, feeling, or 'what it’s like to be something'. What's it like to be a dog? Probably quite different from what it's like to be a pineapple. If it is indeed different, that difference lies in the relative consciousness of the two beings.

In a sense, though, not being able to rigorously define consciousness shouldn’t be too much of a problem because we all (presumably) know what it is - we experience it. It's not like we're trying to explain what it is to someone who hasn't experienced it.

How does Consciousness Arise?

Even though consciousness is something we are all familiar with, understanding how it comes about is a different matter.

We are familiar with matter, things like a table. We know that such things are made of atoms and subatomic particles and what we know about the way those particles act and interact explains the properties of the table. We also know that our brains are composed of such particles and the properties of those particles explain the firing of neurons etc.

But our awareness of things like the table, of the world around us in general and of ourselves, in other words our consciousness, seems to be so categorically different from anything composed of or resulting from atoms and subatomic particles that it is very hard to understand how that consciousness could arise from those particles. This is what David Chalmers calls "the hard problem of consciousness".

There are speculative theories about the mechanisms behind consciousness, how it comes about, but none go as far as actually explaining it in such a way that we can see why it has to arise. Thus all present theories are tentative and incomplete.

It should be said though that there was a time when the idea of life was similarly mysterious. We had no idea how it could arise from non-living matter. It was believed to require a life force in addition to the matter. This was before we knew anything about DNA, mitosis, metabolic processes, neuron firings, evolution, abiogenesis and so on. Now that we know a bit about those things, we can see why life would arise from matter and how it would work. It's no longer a mystery.

It could be that in coming years (or decades or centuries) we will make further discoveries about matter that will make the generation of consciousness an obvious consequence of the nature and properties of that matter. We presently don't have such knowledge, but some of the speculative ideas based on what we do presently know are presented below.

Of course, a widely held alternative theory is that consciousness is a property of a non-material soul. This idea is considered below also. Though saying that it is a property of a soul still doesn't answer the question of how it arises. It just sidesteps the question.

Physicalist Theories

Physicalist theories attempt to explain the world in terms only of the entities which are subject to laws of physics - space-time, fields, particles, forces, quantum effects etc. The term 'physicalism' has largely replaced the word 'materialism' in recent times because materialism has an implication that just matter is involved, whereas physics involves forces, light and other entities which do not make up matter or material. The main physicalist theories of consciousness are as follows.

Neuron Firings

The mechanism favoured by most scientists and psychologists is that consciousness arises as an emergent phenomenon from the pattern of electrical firings of neurons in the brain. How this gives rise to consciousness is not understood.

Evidence in favour of this explanation comes mainly from the fact that changes to the firing patterns are associated with changes to the state of consciousness. General anaesthesia modulates the chemical action of neurotransmitters in the neuron synapses, thus suppressing electrical activity, in particular communication between different parts of the brain. This results in a loss of consciousness. Recreational drugs also affect neurotransmitters and hence firing patterns, leading to altered states of consciousness, though generally only removing it altogether if one takes too much. Endogenic chemicals like adrenalin can affect the electrical activity as can the physical and chemical changes that come with Alzheimer's and other conditions.

Quantum Effects

A variation on the theory of neuron firings is that consciousness depends not just on the firing of neurons, but on quantum effects related to molecules inside microtubules in neurons. These can include superposition, wave function collapse and entanglement. This theory aims to circumvent the seeming difficulty of deriving consciousness from purely classical mechanical processes.

However, it would still be dependent on physical processes, just quantum rather than electrical. Also, there is little evidence to support the theory, and one major difficulty is that many of the proposed quantum effects are only observed at temperatures close to absolute zero rather than in the warm wet conditions inside a brain. Wave function collapse would happen much to quickly in the environment proposed (generally in about 10^-13 seconds).

Roger Penrose sees consciousness as a fundamental property of the universe. He sees it as how quantum collapse looks from the inside, matter being how it looks from the outside. He sees the whole universe since the big bang as having a proto-consciousness. When the complexity of matter becomes sufficient for large numbers of collapses to occur in an organised way, as in the brain, the result is consciousness like we feel as humans.

This is the 'Orchestrated Objective Reduction' theory. The video below is a talk by Roger Penrose explaining this in more detail.

The video comes from Facebook. (url visible in the page source code)

A variation on the quantum effects theory was proposed by Matthew Fisher. He proposed that the quantum effects happen in the neuclei of atoms, phosophorus atoms in particular, where they are better protected from the particle interactions which lead to wave function collapse.

Of course, none of these physicalist processes would lead in any obvious way to what we experience as consciousness.

Panpsychism

A more extreme theory is that consciousness is a fundamental property of the universe, extending to all entities, including atoms and subatomic particles. More complex structure have more complex consciousness.

Compatibility with Physicalism

These models physical are compatible with a physicalist view of the universe. None are supported by current physics, though they are not incompatible with it. Indeed, consciousness might lie outside of the scope of currently known physics, yet still be an aspect of a physical universe.

It might also be said that phenomena like extrasensory perception aren't incompatible with a physicalist view of the universe.

At the turn of the 20th Century, we had no idea of quantum physics or that particles could be in multiple states at the same time. Even now, quantum entanglement seems, at first glance, to defy relativity and certainly defies intuitive classical mechanics. Two particles, even lights years apart can be expressions of a single wave function, making them dependent on one another, one reacting instantly when something happens to the other. Minds could, through processes as yet unknown to physics, be connected in a similar way to other minds, to other current happenings or even to happenings in the future. The fact that, most of the time, we do not see this does not mean that is cannot happen.

The page on The Paranormal looks further into these ideas in the section 'Extrasensory Perception'.

Dualist Theories

Dualist theories are ones which assume the existence of a part of us which is not part of the physical universe or our physical brain and which is therefore not dependent upon the physical brain. Probably the majority of humans are dualists. The non-physical part of us is often called a soul or sometimes a spirit. We will use that term 'soul' here.

Dualism allows various theories of consciousness. We will look at two here.

Consciousness is Independent of the Brain

In this view, consciousness is purely a property of the soul. The conscious soul acts on the brain to get it to do what the soul wants. The advantage of this view is that it lends itself very easily to the idea of a life after death, again something which most humans believe in.

The main disadvantages are firstly that it requires things to happen in the brain which defy the laws of pysics as we understand them, and secondly that it fails to explain how consciousness can be altered or eliminated by physical or chemical changes to the brain like injury, amyloid plaque in Alzheimers, general anaesthesia or psycho-active drugs.

Consciousness Arises through Interaction of the Soul and the Brain

The soul can affect the actions of the brain and determine or at least affect its decisions. But also, the consciousness of the soul is modulated and limited through interaction with the brain. It could be that, without this modulation, the consciousness is much broader than what we normally experience. In some situations where the brain ceases to function normally, one might experience this less restricted consciousness. Examples might be near-death experiences and maybe the use of psychedelic drugs. This restriction and modulation could be an adaptation to allow us to function effectively in the physical world where being able to focus attention on just one thing can be important.

This model would allow for continued conscious existence after death. However, it still has the problem that activity of the brain would need to defy the laws of physics.

Many people who have had near-death experiences become convinced that death is not the end of consciousness. However, the experiences that lead to this belief could well result from abnormal activity of the dying brain. This is discussed more fully on the page The Paranormal in the section 'Near-death Experiences'.

Evidence presented in that section, however, shows that near-death experiences are not obviously compatible with the assertions of any mainstream religion or the idea that religious people have a good afterlife and atheists have a bad one.

Degrees of Consciousness

Consciousness does always seems to involve memories, perhaps along with current sensory input. It seems reasonable to assume that it relies on these and results from them. It is hard to imagine someone with no memory and no sensory input having anything to be conscious of. They wouldn’t even be aware of the lack of memory or sensory input, because, having no memory, they wouldn’t know that such things could exist.

A human embryo with the beginnings of a brain would be unlikely to have much of a consciousness. It seems likely that a rudimentary and very limited consciousness develops in the womb (from sounds and maybe feelings), and that a much fuller consciousness starts to develop once the baby is born and experiences a greater variety of sensory input.

If an embryo had the consciousness of an adult, it would get very bored with 9 months floating upside down, doing nothing but giving its mother the occasional kick. Also, if consciousness were an all-or nothing phenomenon, then it would have to have started at an instant in time. It would be hard to see how this would happen in the context of the gradual development of the embryo and its nervous system.

So it would seem that there can be degrees of consciousness ranging on Earth from nothing to that of the most conscious human. In general, humans have a well-developed consciousness. Dogs appear to be conscious too, though maybe less so than humans. Spiders may have a rudimentary consciousness. But bacteria probably don’t. If consciousness results from brain activity, having a brain would probably be a pre-requisite.

It is conceivable that extra-terrestrials millions of years ahead of us in their evolution might have a degree of consciousness that we couldn’t imagine. Or in fact that humans might get to that state if we survive long enough.

Consciousness is Unobservable from the Outside

One thing about consciousness is that it cannot be seen by an outsider: only the person experiencing it knows it’s there. I know I’m conscious, but cannot tell if anyone else is. Because they seem to be very much like me – they converse with me the way I converse and seem to know and think similar things to what I know and think, I tend to assume that they are.

But then a computer programmed with artificial intelligence can hold a conversation with me to the extent, that, if I am talking to it online, I cannot tell that it isn't human. So, either that is not a sufficient criterion for consciousness, or I have to assume that the computer is conscious. That sounds unlikely, but then I have no way of knowing. In a sense, our brains are complex computers which manifest a high degree of consciousness. Maybe simple computers have a very basic consciousness.

Split Brains

The corpus callosum is a bundle of around 200 million nerve fibres which connect the two hemispheres of the cerebral cortex.

It was discovered in the 1960s that cutting the corpus callosum could cure otherwise intractible cases of serious and debilitating epilepsy. The idea was that the separation of the two halves would stop the chain reactions of nerve firings crossing back and forth between the two hemispheres. Not only did the procedure produce the desired result, but the patients seemed to be fairly normal afterwards.

However, researchers experimenting with split-brain patients found some interesting things.

The left side of the brain receives visual information from the right half of the field of view and vice versa. It also receives sensory information from the right half of the body and controls the movement of the right half of the body. The left half of the brain produces and understands speech; the right half seems to be able to understand to some extent, but cannot generate speech at all.

The researchers flashed images to the right side of the patient’s field of view and asked what it was. The patient answered correctly. But, when an image was flashed to the left half of the field of view, the patient said they didn’t see anything. However, when showed a group of objects, one of which was what had been flashed, the patient could pick out the correct object with their left hand. When asked why they had picked that object, the patient made up some story to justify it.

What seemed to be happening was that the left half of the patient’s brain had a mind that was unaware of what was going on in the right half of the brain. It could get clues by seeing what the left hand was doing, but would only see the actions, not be aware of the thoughts. So it had to make up reasons why the left hand did certain things.

It was possible to hold a conversation with the left-half mind because it could speak, but the right half, while it seemed to have some understanding of what was said to it, could only communicate through body movements.

In most cases, the right brain seemed to be meekly cooperative with what the left brain was trying to do, though not always. On one occasion a patient was buttoning up his shirt with his right hand while his left hand was unbuttoning it again. On another occasion, the left hand tried to strangle the patient and the right hand had to fight it off.

Left-half minds generally said they didn’t really feel any different after the operation and seemed to be just as conscious as before. However, the right-half minds seemed to have a will of their own and, though they couldn’t speak, it seems that they might well have their own consciousness. This suggests that split brain patients could have two independent minds.

One is left to wonder whether the mind is really the well-defined, discrete, unified entity that we tend to think it is.

Finally, if there is a heaven and a hell, it would be conceivable that, in the case of a split-brain patient, the right half could be bound for heaven while the left half is bound for hell. This is difficult to reconcile with religious views of identity, judgment and an afterlife.

Ultimately

Ultimately, how consciousness arises is something that we don't understand. We have theories. It may be that one of those theories turns out to be in some regards right. Or it may be that a proper understanding is totally different from any ideas we have now. It may depend on aspects of the world of which we are presently totally unaware, the way we were totally unaware of quantum phenomena before 1900.

The best we can do now is to be aware of the issue, have some familiarity with the theories, but accept that we don't have the understanding required to resolve the question now, and probably won't have it before we die. In fact it is quite conceivable that the question can never be satisfactorily answered from a human viewpoint.