In my philosophy classes in college, I was particularly intrigued by the philosophy of mind, especially the mind-body problem and the qualia problem (the latter also known as “the hard problem of consciousness”). Recognizing that the brain is a physical organ that is implicated in what we observe to be mental processes, the mind-body problem wonders: What is the relationship between body and mind? Where does consciousness come from? Recognizing that consciousness entails subjectivity, the qualia problem wonders: Why and how do we have first-person mental experiences at all?
Consciousness is interesting because it is not objectively observable. We can observe the correlates of mental activity — we can see chemical reactions, we can see different parts of the brain light up with electrical impulses — but we do not know whether what we are observing are causes of consciousness, effects of consciousness, identical with consciousness, or even mere strange coincidence (thought this last does seem unlikely). Our only observations of consciousness as such are our personal experiences — essentially, that we are aware of our own existence and that we know what it is like to be ourselves — but those cannot be directly shared, only recounted to another mind that we infer is conscious as we understand ourselves to be conscious.
We can’t really know what another person experiences. We can infer a kind of consistency in the observable world, because — subject to individual sensory limitations — we can each look at a red apple and agree that it is red, and we can look at a red tomato and agree that it is red, and therefore conclude that apples and tomatoes must look similar to each of us. But as we look at that apple or tomato together, I do not know that your mental experiences truly match mine. I do not know that, if I were to see what you see, it would be the red that I see. As far as I know, what you see for the color of the apple might be a different color altogether than what I know as “red”; If I could see the apple as you see it, inside your own subjective experience, I might discover that the color you see is not the one I know as “red” at all, but something else entirely. Your red might be my blue.
We also don’t really know that any other persons are conscious beings at all. However unlikely — and I think there are good arguments that it is indeed highly unlikely — we cannot say for certain that other people actually have subjective experience. Plenty of evidence does support the inference; the fact that the world is so full of books I didn’t write, pictures I didn’t take, art I didn’t make, suggests that by far the most economical explanation is that the world is full of other minds besides my own. Yet alternative explanations cannot be ruled out; among the possibilities is that I inhabit a delusion, entirely the product of my own mind, and that what I think is my subjective experience of an external world is no such thing at all. Not a terribly interesting possibility, perhaps, but in my opinion I do lack the basis to be absolutely certain that it is not true.
A friend of many years loathes the taste of peaches, whereas I quite enjoy it. As I have not generally found peach to be a controversial flavor — in my experience the more common complaint by far is the fuzzy texture of the peel — I was interested to explore whether we were experiencing different taste sensations, or simply had different responses to a flavor that we could reasonably determine was recognizably the same to both of us. After all, there are two different experiences involved in the taste of a peach. One is the sensory experience of the flavor itself; the other is the mental experience of that sensation being enjoyable or otherwise.
Put another way: In looking at an apple we agreed was red, could we ascertain that we both meant the same thing by “red”?
We each went to some trouble to analyze the flavor of peaches, to recount our experience of the sensations involved. We might as well have been writing notes from a wine tasting, what with all the reaching for vivid comparisons that we hoped would find cognates in the other person’s experience. We had to probe the sweetness, the brightness, the tang, the acidity. This note on the roof of the mouth, is it like this for you? This little background tingle, do you recognize it? We dissected the subjective experience of the flavor of a peach until it seemed that we could draw but one conclusion: We agreed about what peaches taste like.
And yet we were still not experiencing the same thing.
It’s often said that there is no accounting for taste. Going into the experiment, I had thought it not unlikely that, when a person doesn’t like something that most people do like, that person is actually experiencing sensations that are different in some crucial way. A classic example would be cilantro; some people like it, and some people say it tastes like soap. Since most people don’t make a habit of eating and enjoying the flavor of soap, it seems reasonable to think that people’s experiences of cilantro must be materially different from each other. So, why not think that we might also discover a crucial difference in our perception of the taste of peaches?
To one of us, the taste that we so laboriously characterized was enjoyable. To the other, it was repugnant. Some other mental activity besides the sensation of the peach itself was implicated in the experience.
Why would certain substances, acting on certain chemoreceptors, triggering apparently similar activities in the gustatory cortex, produce the same set of subjective sensory experiences but a different hedonic mental experience?
On one level this is a trivial question. Negative past experiences and associations, the operation of allergic responses, evolutionary adaptations to avoid consuming dangerous substances, even the hypothesis of mere random differences in the hedonic wiring could all play their part in why a person would not have a pleasurable experience with any given food. Research has shown that the brains of people who avoid eating — for example, due to an eating disorder like anorexia nervosa — exhibit a weaker-than-typical response to flavors that are generally agreed to be pleasant.
On another level, though, this is not a trivial question at all. The fact that in our brain activity there are observable correlates, not only for the experience of disliking a taste, but also for potential mechanisms of “learning” the dislike, does not explain the subjective experience of the dislike itself — the “what it is like” of not liking a peach. Suppose there really are just random differences in the hedonic wiring; even so, being programmed to avoid eating certain foods does not explain having particular subjective mental experiences about what it is like to eat those foods.
Awareness of one’s own mind is at the heart of human existence. Descartes said it: Cogito, ergo sum, “I am thinking, therefore I am.” Since I am aware of my own first-person mental experiences, there must be an “I” here. Even recognizing that our senses can mislead us, or that, as in dreams or memories, our minds can conjure perceptions of things that are not there, Descartes could see no reason to disbelieve the fundamental fact of his own experience of mind.
And yet, there’s an unacknowledged assumption in Descartes’s formulation — namely, that it must be an “I” doing the thinking. To say more here than “thinking is happening” is arguably to assume the thing that he sets out to prove.
So, does the experience of mind truly entail an “I”? It has often been thought so. Descartes believed that there is a human soul, and that it resides in the pineal gland. A modern reductive materialist would reject the idea of a pineal-gland-resident soul as such, but would believe that consciousness is totally reducible to the operation of brain functions. Either way, where there is a brain, there is an “I”.
But there is another possibility. The brain may be like a radio, tuned to a particular frequency. There is no music “inside” a radio; measuring the bare physical facts of the radio’s internal operations does not reveal the content of the music as such; the music itself is broadcast from somewhere else, encoded in electromagnetic waves that the radio receives and renders perceptible by our ears as the sounds of Rick Astley.
So, perhaps the brain does not provide a residence for consciousness, nor produce consciousness, but merely receives it, picks it up from somewhere else, renders it cognizable. The hedonic wiring of a given brain might determine whether the taste of a peach registers as good or bad — is the radio tuned to the oldies station or to smooth jazz? — but “what it is like” to enjoy or not enjoy the peach could originate outside the brain altogether.
Who knows, maybe the whole universe comprises a self-perceiving totality, and our brains just happen to collapse that perception to something local. Imagine a wave function describing a vast superposition of quantum states, essentially the entire range of all possible subjective experiences, collapsing to a single measurement due to the act of observation. The radio can tune to many stations; the air is full of boundless music all at once, yet the radio plays only one station at a time.
I could experience what it is like to enjoy peaches, and you the opposite, because the eigenstates of the wave function comprehend both possibilities. The quantum state of consciousness of the universe experiencing the enjoyment of peaches is locally measured at one sensor as “my experience”; the quantum state of consciousness of the universe experiencing the dislike of peaches is locally measured at another sensor as “your experience”.
The “I” of my consciousness may just be the fact that the universe is observing itself, right here in the chair where I sit.
In other words: Thinking is happening, therefore something conscious exists.