Let us begin with incontrovertible facts.
The body is conceived by the union of a sperm and an ovary, it comes out of the mother's body after nine months (considered the event of birth), it grows through childhood and youth, passes through adulthood and middle age, suffers old age ... And when one of the organ systems in the body fails to function properly, it falls into disease and finally when the organs are unable to sustain further life, it becomes inanimate, lifeless, cold and decomposes (called the event of death).
The body is born with certain innate tendencies of action and thought; and more are acquired as it is conditioned by the environment. Various kinds of conditionings make their mark on the brain and the rest of life is spent in a more or less predictable pattern of behaviour. There are deviations, and discontentment; but they too have discernible causes. One learns some skills and languages, one learns the customs of the society, one begins to influence the environment (though being a part of the whole), ...
The day of the body is spent in various mental and physical activities, and usually at night, the body is laid to sleep. In sleep one experiences dreams and imaginary worlds, and also dreamless states of deep sleep.
One remembers events from the past, and, to a lesser extent, from one's dreams. This is called memory. Memory is partial and selective. One does not remember everything. However, sometimes a memory is also inaccessible. One is unable to recall something consciously, but one remembers suddenly, in a dream, or under hypnosis or the influence of a drug.
The experiencer, at least in the vast majority of mankind, does not any have memories of events before one's birth and beyond one's sensory horizon. Such events are remembered by the communication of others. The sensory horizon (i.e., how far one's eyes can see, how slight a sound or smell one can distinguish etc.) limits one's knowledge of the outside world.
However, there is also an inner world of thoughts, feelings and sensations. And by training, one can learn to look at them as if from a vantage point beyond the body. This is usually called awareness of the mind and body. I say "as if", because it may be that it is just a part of the mind observing the rest of it and the body.
The body is composed of various chemical elements. It is affected by outward stimuli. The senses are based on physical and chemical contact with foreign objects. The body is a changing whole of cells, membranes and molecules. Throughout life, various parts of the body are continously worn out and refurbished, but as a whole, the body retains its continuity of form.
Apart from the sensations of touch, sight, sound, smell and taste; there are inner sensations and mental events.
Inner sensations may be localized or non-localized. Hunger, nausea, headache and so on. But still, their dependence on the physical, bodily nervous system is demonstrable. A pill or an injection can affect inner sensations.
Mental processes and events are more complex. If one observes one's thinking, most of the time it is seen to be involuntary. The mind indulges in random chatter. An active brain (i.e., involved in thinking or imagery) is seen to leave electrical traces on the EEG, whereas a brain during deep sleep leaves an entirely different scan. Hence, thoughts and imagery can be said to co-occur with physical processes in the body. Science as yet has been unable to fathom the exact nature of thoughts in a subject's brain merely from reading a scan of its electrical activity. For example, as of now it is impossible to say from an EEG whether a man is thinking of his mother or of his father.
Let us now move on to speculation.
Let us, for the moment, distinguish the physical brain and the abstract content of thoughts and imagery. Obviously, there is an interrelationship. But whether there is an identity is another matter. Drugs and trauma can affect one's thought processes, and thought processes co-occur with electrical impulses in the brain.
Trauma can lead to permanent or partial loss of memory, drugs can increase one's libido, irritability and even one's peacefulness (consider the class of drugs known as SSRIs and benzodiazepines).
Let us conjecture, that the electrical and chemical impulses in the brain are the alphabets of thought processes. The actual content of thought processes can be known only when one understands the language of these signals. It is a similiar notion to that of a book written in a foreign language. The story is not merely the collection of symbols. It is what the symbols represent. The story can be said to be what is common in various expressions of the book in different languages. The book is a picture of the story. In the same way, we are saying, let us consider the brain as a picture of the mind.
Is this conjecture feasible? First of all, is the brain a "private picture"? I.e., is it that the symbol table is individual and not universal? It is very likely that it is so. One man thinking of one's father may have an electrical signal in his brain entirely different from another person thinking of the first person's father, or another person thinking of his own father. Hence there seems to be a conceptual impossibility to derive thought content from an electrical scan (no matter how minute).
Hence this conjecture is at best only partially verifiable. Testing on a large number of holocaust survivors with questions about Hitler may give an indication as to what electrical signal in their brain corresponds to a thought of Hitler. In this way, the private language of even an individual brain can be slowly learnt by statistical testing (by repeatedly taking scans and asking the person what he is thinking about). If there doesn't seem to be a pattern at all in the experiment, one could conclude that the picture theory is incorrect.
Is there any other theory possible? Let us conjecture that the mind is a non-material entity corresponding with the physical brain. An event in the brain may co-occur with a mental event or it may just be a physical event. A hope is a mental event, feeling of hunger is a physical event. We call those events mental, which involve thinking, reasoning, feeling abstract emotions such as love, fear and regret, and remembrance or speculation. On the other hand, physical events are merely perceptions of one's body sensations.
Feelings can be long drawn, devoid of imagery (e.g. a feeling of happiness), or they may be verbalized and short-duration (e.g. reasoning about a mathematical problem).
It has been suggested that the mental events ALWAYS co-occur with certain physical events. For example, it is said, anger co-exists with increased surface body temprature and increased muscle tension. Is this suggestion reasonable, considering our conjecture?
Let us ask ourselves what physical event corresponds to my acceptance of communism as a valid ideology. Certainly certain neurons in the brain are now wired in a certain pattern. But apart from the brain, is there any other physical change? It seems very unlikely. But it is said, an acceptance of communism is not a mental process. It is only an event, at which time there may also be a physical event in the body. Later, when I hear some criticism of communism, a physical reaction may develop in my body as a co-occurence of my mental aversion.
But, it is clear that the PRIMARY bodily event corresponding to a mental process or event occurs in the brain. The rest of the body, being connected to the brain (and to a large extent, controlled by it) is affected concurrently.
Correspondence in this direction is fairly easy to understand.
What about the body affecting the mind?
Certainly, ill-health of the body can give rise to depressive states in the mind. And, anti-depressent drugs can elevate the mood.
Hence there is at least some causal relation between the body and the mind. Can ALL mental states be affected by physical causes? Is it possible to think of a mental state which is not affected by one's physical disposition, by one's history of interaction with the world? It is hard to think of anything like that. It seems all our mental concepts, fears, hopes and dreams originate from sense experience. What about abstract thinking? What about philosophy, mathematics, theoretical physics, creative arts and music? Are these dependent on sense experience in any way?
Of course, one's upbringing may nurture some particular aspect of the mind. And it is seen that as one grows old, one's creativity and energy level decline. Usually, the most creative period of one's life is one's youth. Is it merely a coincidence? Reasoning is certainly affected by brain decay. Hence we can rule out philosophy, mathematics and science, all of which require the capacity to ratiocinate. What about art? What constitutes art is a difficult issue. But certainly, brain chatter continues even in a decayed brain. If art is considered to be a expression of what is considered beautiful, then this perception first occurs in the artist's mind. What is the likely source of this event? Is it a selection from random events in the brain, later enhanced by skill and mastery of one's medium? It is possible.
Hence, it seems like every mental event can be explained by physical causes. But then, is there any prima facie reason to suppose the mind is non-material? No.
Is there any difference between the mind and consciousness? Consciousness is said to be the awareness that accompanies life in animals and humans. For humans, consciousness is either of brain processes or of sense experience. Is there any consciousness when the brain and the body are both at rest (deep sleep)? What would consciousness mean in such a scenario? The basic, implicit consciousness is the consciousness of BEING. Is it reasonable to suppose that consciousness of being even survives deep sleep or brain death? It is only possible to ask the person as to whether he was conscious of being when he was in deep sleep. No such questions can be asked to persons who have suffered irreversible brain damage, but maybe a person who wakes from a coma can provide an answer. It seems, however, that one remembers being in deep sleep. One does say, "I slept very soundly tonight."
So one can reasonably suppose that consciousness of being, in other words, self-consciousness, continues irrespective of the state of one's brain.
What constitutes memory? Who remembers dreams and deep sleep? Is experiencing and subsequent memory a function of the brain or of this "mysterious consciousness"?
We should notice that we are introducing a separation here. We are distinguishing phenomena and their awareness. Sense experience and mental events both are perceived by consciousness. Consciousness is the "eye behind the eye", the "ear behind the ear". Does the eye know that it sees? The faculty of knowing, or of awareness, is attributed to consciousness. This should be distinguished from knowledge, which is but a refined form of memory.
Is there any other attribute of this consciousness other than being aware? If I am merely aware during deep sleep, how come there is a remembrance of that state? Where was that memory etched? Who records the (so-called) experience of deep sleep, if not the brain? Let us, therefore, attribute to this consciousness a faculty of remembering as well, distinct from the memory we associate with the brain. Is this justifiable? This new device introduces a factor of complexity not previously there.
Let us imagine that this consciousness, this sense of "I am", though inherently separate from the brain, identifies itself with the mind and the body, and there is a therefore a subsequent feeling in the brain that "I am This Body and This Brain," or "This body and this brain are mine". "I am" is not a thought process, but "I am the body" is. Of course this seems to be justified. My knowing comes through this body and this mind, hence I feel that this body is mine. I can observe thoughts and feelings occuring in this brain, hence I say this is "my mind". The only state where I lack this identification is in deep sleep, where there is only the sense of "I am", and no awareness of one's body or one's mind. Even in dreams, I identify myself with an imaginary body (similiar to my actual body) functioning with an imaginary brain (working in a similiar manner to my actual brain).
Another question is what relation this consciousness has with my volition and actions?
Firstly let us consider the problem of memory.
What really happens in a dream? That may give us a clue to who remembers the dream.
One lies down to sleep. The mind keeps chattering, slowly one begins to see visions without one's volition, and the body drifts to sleep.
The body continues to sleep. There is eye movement (REM), electrical activity in the brain signifying the dream state, and sometimes, involuntary gestures, speech, urination and ejaculation of sperm. The person, if awakened while dreaming, seems a little lost for a moment or too, and then he registers his surroundings and "comes to his senses".
If the physical body is not unduly bothered (by a bad posture, by an urge to urinate etc.), the dreams seem to be unconnected to the state of the waking body. Even though for the waking body, the dream state may last only a few minutes, the passage of time in the dream has little relation to it. Days and months may pass in the dream. The primary remembrance of the dream is visual. Next comes tactile memory. Other senses such as those of smell, sounds or taste are secondary (as in waking state). Dreams may be pleasant or unpleasant. Dreams may be novel or repetitive. Usually the body is the same as the waking body at the present period. E.g., each person dreams himself to be the same person as he is in the waking world. And usually, of the same age. However, a dream of childhood may have one's body as a child. Remarkably, however, the cogitation about the dream world that goes on in the dream is done with the present mind, with all its learnedness.
We have three concepts here: Brain, Mind and Consciousness. Since the new body is imaginary, it also has an imaginary new brain with which it functions. Is the mind of the waking state different from that of the dream state? I opine that it is the same, based on what I do in the dream. My desires, conditionings, fears are the same in a dream.
Is it that there is a false transference of brain power? I.e., is it that while I am using my waking body brain (while the body is asleep), it seems to me that I am working with the brain of my imaginary body? It is possible. There does seem to be a relationship. For example, if I kick a football in my dream, sometimes the leg of my waking body also kicks up. And the phenomenon of wet dreams is also mysterious. Orgasm in the dream state is usually accompanied by orgasm of the waking body.
And is the consciousness the same? For I remember the dream in a similiar manner to remembering yesterday. The only difference seems to be that memory of a dream fades away very quickly. A couple of days later, I may have only a very hazy notion of what I dreamt tonight. But there is no break in the sense of "I am". Since that is continuous, let us presume that consciousness is the same.
What is the relation betwen the body-brain of the dream and the body-brain of the waking state? Let us offer the following explanation: The consciousness identifies with the waking body in the waking state and with the dream body in the dream state. When the dream is broken, the identification suffers a sudden transfer. This transfer carries over the momentum of the previous body-brain with it. Hence on waking, I may kick up or ejaculate. But is it possible for the waking body to be affected without it being awakened. Yes, that also seems to be true. One can utter words while seemingly fast asleep (and dreaming), and sometimes one doesn't know that one has had a wet dream till the morning, when one observes the stains on the sheets. But in that case, one can say that one is not dreaming "deeply enough". In a light, intermittent dream such phenomena can occur because consciousness keeps shifting back and forth, or it is only lightly separated from the waking body.
But what about the seemingly deep states of sleepwalking? One can't say that is a light sleep, for the person doesn't get awakened very easily. ??
Let us try the materialistic explanation. There is only one body, the waking body. While asleep, its brain indulges in vivid imagination which are called dreams. Obviously it remembers the dreams when it wakes up. The memory of dreams is weaker than that of waking states because the registering apparatus is not functioning with its full force while the dreaming goes on. And what about deep sleep? Then, there is no imagination. The essential body processes continue and we recall the nothingness, i.e. that we did not indulge in noisy dreams, as having slept soundly. There is no consciousness other than that inherent in the brain as the capacity to register mental and physical events.
But this theory leaves a lot to be desireed. Consciousness is yet to be localized in a specific part of the brain. If it is indeed part of the body, where is it? And when in deep states of meditation, when there is only silence in the mind, there is obviously a consciousness of this silence. Consciousness seems to be a very different phenomenon than mere physical events. I have the distinct awareness of my being. Is it a brain process? Let us say it is a series of physico-chemical reactions in the brain. But consciousness is an un-interrupted stream of awareness (at least) from birth to death (at least in the waking state). What is this un-interrupted stream? It is not a discrete process like the beating of the heart or the functioning of the liver. One can observe changes in these organs when they are functioning. What is the ceaseless process in the physical body which corresponds to consciousness? What is its frequency? No, consciousness does not appear to be a process.
Mental states correspond to brain processes, no doubt. But consciousness is not a process, it is like existence. It just is, without a gap or underlying process which causes it.
So where are we now?
Consicousness is a mysterious entity, like existence. It pervades the living beings. Humans can, however, be aware of their being conscious and can observe even their own minds. Consciousness alone is non-material in the world, the rest is all physical phenomena, or phenomena dependant on physical phenomena. Body processes, brain processes, mental events are all unconscious. It is the light of consciousness which shines on them and they are then perceived.
Nothing is solved by speculation.