Consciousness As Mental, As Physical

It’s been argued that a scientist who grew up in a black and white room and never saw the color red could learn everything there is to know about the physics of light and the physiology of the human body, including what happens in the brain when someone sees red, but not know what red looks like. Presumably, a blind scientist with the same training would be in the very same position. Likewise, a deaf scientist could know everything about the physics and physiology involved in hearing a violin but not really know what a violin sounds like. This is supposed to show that there is something in the universe beyond the reach of the physical sciences: the mysterious mental phenomenon of consciousness.

“Mental” is a word I haven’t used much (or at all) in writing about consciousness, yet consciousness is clearly a mental phenomenon if anything is. But what does it mean for a phenomenon to be “mental”?

The obvious answer, although it’s not very helpful, is that “mental” means “not physical”. But what does that mean?

An exchange of letters I referred to last month between the philosopher Thomas Nagel and a professor of bioengineering, Roy Black, tries to deal with the question. Prof. Black criticizes the idea that “nonphysical factors” are involved in consciousness:

As is frequently noted, the physical basis of life itself used to be just as mysterious as consciousness, and it’s now well explained by biochemistry and molecular biology, without nonphysical factors. So although science as we know it doesn’t explain the link between neurons and consciousness, why expect the link to be “nonphysical” rather than “novel physical”? What is a nonphysical factor, anyway? If the dark energy propelling the expansion of the universe, the strong force holding atomic nuclei together, etc., etc., are physical, do we really need anything more exotic?

… Lots of things in biology—like the development of an organism from an egg—seem impossible, until we stretch our imagination to conceive of simple precursors and mechanisms that could have been worked on by natural selection over billions of years. To quote one of [the philosopher Daniel Dennett’s] nice lines, “evolution is a process that depends on amplifying things that almost never happen.” We need to determine what “thing,” what activity of neurons beyond activating other neurons, was amplified to the point that consciousness arose. What would a precursor of “feeling like” be? That’s what we need to stretch our imaginations further to figure out.

Prof. Nagel responds, but his response is based on an assumption:

The difficulty is that conscious experience has an essentially subjective character—what it is like for its subject, from the inside—that purely physical processes do not share [how does he know this?]. Physical concepts describe the world as it is in itself, and not for any conscious subject….

I agree with Black that “we need to determine what ‘thing’, what activity of neurons beyond activating other neurons, was amplified to the point that consciousness arose.” But I believe this will require that we attribute to neurons, and perhaps to still more basic physical things and processes, some properties that in the right combination are capable of constituting subjects of experience like ourselves, to whom sunsets and chocolate and violins look and taste and sound as they do. These, if they are ever discovered, will not be physical properties, because physical properties, however sophisticated and complex, characterize only the order of the world extended in space and time, not how things appear from any particular point of view [again, how does he know this?].

Nagel’s assumption is that a purely physical process cannot have a subjective character (it cannot “feel like something”). It cannot be “how things appear” from a particular point of view. But if consciousness is a physical process, it does have a subjective character. In that case, how things feel or appear are indeed physical properties of a process that occurs in space and time (it happens inside your head when you’re conscious).

Here’s my take on the mental/physical distinction. Nobody knows what the universe contains at the most fundamental level (or if there is a most fundamental level). But suppose that quantum field theory is correct and, quoting Prof. David Tong of Cambridge University (who I wrote about earlier this year):

The best theories we have tell us that the fundamental building blocks of nature are not particles but something much more nebulous and abstract. The fundamental building blocks of nature are fluid-like substances which are spread throughout the entire universe and ripple in strange and interesting ways. That’s the fundamental reality in which we live. These fluid-like substances, we have a name for, we call them “fields”.

Furthermore, when the fields ripple or are agitated in certain ways, we get sub-atomic particles. An electron, for example, is a kind of ripple in the electron field.

So when I say that consciousness is a physical process, what I’m saying is that consciousness is at bottom constructed from one or more quantum-level fields – or whatever the fundamental building blocks of the universe are – that somehow interact with the quantum-level fields – or other building blocks – from which everything else in the universe is constructed. Maybe consciousness involves a kind of fundamental field that physicists can’t measure or detect yet. Maybe it involves a new kind of interaction between fundamental fields that physicists already know about.

But consciousness seems to be part of the natural world in the same way other physical phenomena are. And because it’s part of the natural world – not a kind of free-floating spiritual or supernatural substance or phenomenon – consciousness can represent other physical events and processes outside itself. Consciousness being part of the world is why we can be consciously aware of our bodies and the world around us.

“Mental”, therefore, refers to what happens in our minds, but at bottom mental phenomena are physical phenomena. Consciousness, like gravity, digestion and baseball, is one of the things that happens in the world. In other words, the “mental” is a subset of the “physical”. Or so it seems to me.

The Way Consciousness Is

Thinking about the United States plumbing the depths of kakistocracy (rule by the worst) is all well and good, but back to consciousness.

The human brain is the most complex object anyone has ever tried to understand. It might be the most complex object in the universe. We might never understand how it works. Robert Burton, a neurologist, writes about being surprised by a patient with a paranoid fear of the FBI that was apparently caused by a mutation in his brain:

Though I didn’t know it at the time, I had run headlong into the “hard problem of consciousness,” the enigma of how physical brain mechanisms create purely subjective mental states. In the subsequent 50 years, what was once fodder for neurologists’ late night speculations has mushroomed into the preeminent question in the philosophy of mind. As an intellectual challenge, there is no equal to wondering how subatomic particles, mindless cells, synapses, and neurotransmitters create the experience of red, the beauty of a sunset, the euphoria of lust, the transcendence of music, or in this case, intractable paranoia.

Neuroscientists have long known which general areas of the brain and their connections are necessary for the state of consciousness. By observing both the effects of localized and generalized brain insults such as anoxia [total lack of oxygen] and anesthesia, none of us seriously doubt that consciousness arises from discrete brain mechanisms. Because these mechanisms are consistent with general biological principles, it’s likely that, with further technical advances, we will uncover how the brain generates consciousness.

However, such knowledge doesn’t translate into an explanation for the what of consciousness—that state of awareness of one’s surroundings and self, the experience of one’s feelings and thoughts. Imagine a hypothetical where you could mix nine parts oxytocin, 17 parts serotonin, and 11 parts dopamine into a solution that would make 100 percent of people feel a sense of infatuation 100 percent of the time. Knowing the precise chemical trigger for the sensation of infatuation (the how) tells you little about the nature of the resulting feeling (the what).

But why should we expect that knowing what chemicals cause the feeling of infatuation would tell us anything about what infatuation feels like? Aren’t those two different questions?

Suppose, however, that we keep improving our techniques for studying the brain, as Burton suggests, and eventually figure out how certain kinds of brain activity become consciousness. It doesn’t seem impossible that one day (maybe 1,000 years in the future) that we will fully understand how “subatomic particles, mindless cells, synapses, and neurotransmitters” allow us to be conscious, just as well as we understand how lungs allow us to breathe (although lungs are a lot less complicated than brains). Suppose we discover how one kind of brain activity becomes a feeling of infatuation and another kind becomes a feeling of resentment. 

Burton implies that we would still be left with what he calls the “what” question, although it might be better to call it the “why” question. Why does our consciousness have the specific properties it does? Why does a note on a violin sound just the way it does? Why does red look like this and not like this or this? In the case of color, scientists might understand perfectly well the relationship between different wavelengths of light, the physiology of our eyes and nervous system, and the colors we see. They would understand that such and such conditions, structures and processes are correlated with seeing red and others are correlated with seeing blue. All of our “how does this happen?” questions would have been answered. So would it still make sense to ask why a particular kind of light looks the way it does or a particular feeling feels the way it does?

I’m not sure it would. Once we understood what leads to colors looking the way they do, or what makes feelings feel the way they do, any “why” questions might disappear. Once we understand the “how” of consciousness, maybe there won’t be anything more to figure out. If there are any neurologists or philosophers still asking “why”, the best answer will be “that’s just the way it is” or “stop asking questions and go to sleep”.

That wouldn’t necessarily be a bad thing. After all, in science, we sometimes arrive at what appear to be “brute” facts. Why is the speed of light in a vacuum 186,282 miles per second instead of 186,300 miles per second? We may never know. That’s just the way the universe works. No further explanation is available. If you have a problem with our speed of light, go live in another universe. If you don’t like the particular colors you see, keep your eyes closed. Or become a cat.

Next up on this subject, assuming I stay conscious: What does it mean to say consciousness is a physical phenomenon? It’s obviously a mental phenomenon, so how can it be a physical one too?

What We Have In Mind (Consciousness Again)

Last week, I suggested that consciousness is a type of brain activity, the kind that consists in having a phenomenal field that includes sights, sounds, pains and the internal monologue depicted by authors as the “stream of consciousness”.

I also recommended that we reserve the phrase “conscious of” for the most important things we’re conscious of, things like our everyday surroundings, our feelings and our thoughts, not consciousness itself. This approach would rule out questions like “Are you conscious of consciousness?” that to me seem misguided and misleading. I don’t think we’re conscious of consciousness, but rather conscious of other things.

To say that we’re conscious “of” other things is to say that the components of consciousness represent other things. Thus, some of the brain activity that is consciousness represents things outside our bodies (e.g. trees falling in the forest). Some of it represents things inside our bodies (e.g. heartburn). And some represents things that exist neither inside nor outside our bodies: abstract things like possibilities (e.g. sanity in Washington), fictional characters (Wonder Woman) and ideas (justice or the number twelve).

From an article about dreaming, which is usually considered a kind of consciousness:

One of the main functions of our brain is to constantly create a model of the world around us, a sort of virtual reality that helps us interact with our environment.

When we’re awake, that model is heavily influenced by what we are seeing and hearing and feeling. But during sleep, when there’s not much input from our senses, the brain’s model of the world is more likely to rely on internal information, like memories or expectations.

I’d add that the model is also a model of the world within us and the abstract world of memory, intention and imagination. But thinking of the model our brains create as “a sort of virtual reality” is what I have in mind (that’s a pun). It’s the “sort” of virtual reality that isn’t virtual, however. Patterns of neural activation in the brain (what the model is made of) are quite real. And it’s a model or representation of other things that are quite real too, like falling trees and sprained ankles.

One of the things that makes our conscious model interesting is that it includes events and processes that are strictly or primarily mental, like having a premonition. I don’t know if such things are representations of unconscious mental events and processes. Maybe they aren’t representations at all; maybe they’re patterns of neural activation that don’t refer to or represent anything else. But the evidence suggests that we all have a lot of unconscious brain activity that plays a very large role in what we think and how we feel.

So it would be consistent with the view I’m trying to explain that when you have something like a premonition, what you’re conscious of is a representation of the underlying brain activity (the unconscious premonition processing), as well as any related events in your body (like chills).

To sum up, the position I’ve arrived at seems to be a strange, possibly ridiculous mixture of ideas associated with two great philosophers who are generally seen as opponents: the idealist George Berkeley and the materialist Thomas Hobbes.

Berkeley (1685-1753) argued that nothing exists independently of minds: “To be is to be perceived (or to perceive)”. A person is an immaterial mind or soul. The physical world (the Earth, for example) doesn’t exist independently of our minds. Fortunately, our individual minds are able to get along because God (a kind of super-mind) synchronizes our perceptions. He makes sure that when I perceive a red apple (in my mind), you do too.

Hobbes (1588-1679) argued that nothing exists except physical stuff. We human beings, including our minds, are material things. Even God may be a kind of material being. When I see a red apple, and you see a red apple, therefore, it’s because there’s an apple out there and it’s red. That’s the whole story. 

Where I’ve ended up is to agree with Berkeley that our consciousness has the various elements in it that he called “perceptions” and “ideas”. But I agree with Hobbes that consciousness is a physical phenomenon, a very cool physical phenomenon, but a physical one just the same. And the reason my perceptions usually line up with yours so nicely is because our perceptions represent the same physical world, albeit observed from our individual perspectives. 

Being Conscious, But Not of Consciousness

A reader (!) asks: Does [what you posted about consciousness yesterday three days ago] mean that we are only conscious of what’s going on in our brains?

That’s an excellent question. When I say that consciousness is certain kinds of brain activity or patterns of neural activation, it may sound like I’m saying that we’re only conscious of brain activity. In other words, we’re not conscious of the rest of the world or the rest of our bodies.

Given what I’m saying about consciousness, I might explain that we are “directly” conscious of our brain activity and “indirectly” conscious of the rest of the world. Or I could say that our consciousness of what’s going on in our heads is “immediate”, while our awareness of everything else is “mediated”, i.e. conveyed through intermediaries, such as the air that carries sound waves to our ears and the nerve impulses that travel from all over our body to our brain.

So when I raised this question yesterday (“Does this mean we are only conscious of what’s going on in our brains?”), I began by saying “in one sense, yes, because that’s where the physical phenomenon of consciousness takes place”. I then said, however, that in the most important sense our brain activity enables us to be aware of what’s happening outside our brains.

Actually, I recommend that we reserve phrases like “conscious of”, “aware of” or “what we experience” for the things we are ordinarily and importantly conscious of. That’s the standard way of speaking and the best way to describe what’s happening when we are conscious. For instance, when you’re awake, are you conscious of your surroundings? When you raise your arm, do you experience any discomfort? Now that you’re on Social Security, are you experiencing any memory loss?

Asking whether we are conscious of what’s going on in our brains amounts to asking whether we are conscious of our consciousness. It’s a misleading question. It’s like asking someone at the North Pole which way is north. To be conscious is to have a certain kind of brain activity. To be conscious of whatever is to be conscious of something other than your brain activity. That’s because there is no way to be conscious of your consciousness. There is no mechanism, no mental apparatus, no meta-consciousness that allows being conscious of consciousness. Consciousness just is. The world you see, that rumbling in your stomach, is what it looks like, feels like, to have the right kind of brain activity. 

You can think about being conscious. We’re doing that right now. But that’s different from being conscious of consciousness. When you think about consciousness, you’re conscious of your thoughts (about consciousness), just like you can be conscious of thoughts about other things. But consciousness itself just is (I could say it is what it is, but that would be redundant and annoying).

Could an evil demon be tricking you, like Descartes wondered? Could you be a brain in a vat, like later philosophers ask themselves? Sure, it’s possible to be seriously wrong about what you’re conscious of. Maybe what you’re conscious of isn’t ever what you think it is. I’m not worried. You shouldn’t be either. 

If a tree falls in the forest, does it make a sound? Yes, it makes the air vibrate and if it creates enough vibrations and there’s anyone around who’s conscious and isn’t deaf, they’ll hear (be conscious of) the crashing sound. 

I’m not sure what I’ve been saying makes sense. I’ve thought about this topic for a long time but never expressed my thoughts this way before. Maybe what I’m saying is way off the track, but it’s all I’ve got right now. Maybe I’ll get back to it again. In the meantime, stay conscious.

In my opinion, that implies being conscious of other things, not consciousness.

What’s So Hard About Consciousness? (With More Words Than Usual)

Some philosophers call it “the hard problem”. Here’s how Norwegian philosopher Hedda Hassel Mørch describes it:

The nature of consciousness seems to be unique among scientific puzzles. Not only do neuroscientists have no fundamental explanation for how it arises from physical states of the brain, we are not even sure whether we ever will….

Our brains do not merely seem to gather and process information. They do not merely undergo biochemical processes. Rather, they create a vivid series of feelings and experiences, such as seeing red, feeling hungry, or being baffled about philosophy. There is something that it’s like to be you, and no one else can ever know that as directly as you do.

Consider the colored objects below. Scientists can describe what happens when a person sees them. They can tell you why the color of a tomato is more like the color of an orange than a lemon. They can point out that if you mix red and yellow light, you’ll get orange. They can use words and numbers to say what’s happening as light is reflected into your eyes and impulses are transmitted along your optic nerves. 

 

But scientists cannot express or capture how any of these colors look when they, or you, or I see them. Words and numbers aren’t up to the task! The best anyone can do is show you examples. See, this is red! 

Consider how the word “red” is defined in dictionaries. Merriam-Webster says “red” means “of the color red”. Not terribly helpful. Consider how Wikipedia introduces its article on “Red”:

Red is the color at the longer-wavelengths end of the spectrum of visible light next to orange, at the opposite end from violet. Red color has a predominant light wavelength of roughly 620–740 nanometers. 

That would be helpful in some circumstances, but the Wikipedia writers added color pictures of strawberries, a cardinal and the Chinese flag to make things perfectly clear. That’s because pointing out examples is the best way, in one sense the only way, to express the meaning of a word like “red”. That, by the way, is called an “ostensive” definition. When language won’t do the trick, show an example. 

The same difficulty applies to the way a violin sounds, the way roses smell and the way tickles tickle. There is something elusive about the way the world appears. There is something incommunicable about experience. Another way of saying this is that the contents of consciousness are a first-person phenomenon. Science as the formal study of the world can describe and explain what’s happening when you hear a violin from a third-person perspective, but the particular sound you hear is beyond words or numbers. There is something about being a person, what it’s like to be a person (or a bat), that has to be experienced firsthand.

Hmm.

Okay, well, that’s interesting. But I’m tempted to say: so what?

That hasn’t been the usual reaction in the history of Western philosophy. Many philosophers have drawn big conclusions from the scientific elusiveness of consciousness. Here, for instance, is Thomas Nagel writing in an exchange of letters a few months ago (he is the author of the famous philosophy paper “What Is It Like to Be a Bat?”):

I do not deny that patterns of neural activation cause experience. What I doubt is that patterns of neural activation alone constitute or are experience—if neural activation is a purely physical process.

The mind-body problem that exercises … me is a problem about what experience is, not how it is caused. The difficulty is that conscious experience has an essentially subjective character—what it is like for its subject, from the inside—that purely physical processes do not share. Physical concepts describe the world as it is in itself, and not for any conscious subject…. But if subjective experience is not an illusion, the real world includes more than can be described in this way.

I agree … that “we need to determine what ‘thing,’ what activity of neurons beyond activating other neurons, was amplified to the point that consciousness arose”. But I believe this will require that we attribute to neurons, and perhaps to still more basic physical things and processes, some properties that in the right combination are capable of constituting subjects of experience like ourselves, to whom sunsets and chocolate and violins look and taste and sound as they do. These, if they are ever discovered, will not be physical properties, because physical properties, however sophisticated and complex, characterize only the order of the world extended in space and time, not how things appear from any particular point of view.

Nagel accepts that patterns of neural activation cause consciousness, but he doesn’t think they constitute consciousness. I think he has two reasons for saying this. The first is what we’ve been considering so far: consciousness has properties (“raw feels”) that cannot be captured by science. The second is that neural activation is physical – it occurs in space and time – but, according to Nagel, consciousness doesn’t.

His conclusion is that consciousness is a mental phenomenon that somehow stands apart from the rest of the universe. Our experience is supposedly a special kind of “stuff” that’s somehow separate from the physical world of quantum fields, waves and particles. (How events in space and time can make something happen that isn’t in space or time has always been a problem for positions like Nagel’s. Another philosopher, Daniel Dennett, says it would be a miracle.)

My own view is that patterns of neural activation don’t cause consciousness. Nor are they correlated with consciousness. Instead, certain patterns of neural activity are consciousness. In other words, consciousness is having certain kinds of neural activity.

If consciousness is a certain kind of activity in one’s brain, that kind of activity in one’s brain doesn’t cause consciousness. That’s because a phenomenon cannot cause itself, so saying there is a causal relationship between particular kinds of neural activation and consciousness implies that they are separate phenomena. Nor are such patterns of neural activity correlated with consciousness, because, again, saying that two series of events are correlated implies that they are separate phenomena. But having various patterns of neural activity occurring in your brain can be and is consciousness.

This isn’t to deny that there are correlations of a sort. When a scientist or technician measures or records someone’s brain activity (or even their own), they are collecting data from an outside, third-person perspective, i.e. the perspective of the equipment that does the measuring or recording. Looking at the data that’s gathered, we can say there is a correlation between the data and the subject’s consciousness.

But we shouldn’t go on to say that the patterns of neural activity detected in the brain are correlated with the subject’s conscious experience. That would imply that the neural activity stands apart from the conscious experience, when they’re really the same phenomenon talked about in two different ways or considered from two different perspectives (i.e. the third person “outside” perspective and the first-person “inside” point of view). 

This view is known as the “identity” theory. To me it seems obvious. Consciousness is brain activity. Certain brain activity is consciousness.

Not so fast, however. How can consciousness and having appropriate brain activity be the same? Don’t “they” have different properties? I don’t think so.

Until there is reason to think otherwise, consciousness should be viewed as a physical process that occurs in the brain. Since the brain is in space and time, so is consciousness. When a person is conscious, they are presented with a phenomenal field, a set of representations, including three-dimensional sights (for most of us) and corresponding sounds (for most of us) and smells, tastes and feelings, as well as thoughts (for most of us). Some of these representations have properties like being red or sweet. These properties belong to the components of the phenomenal field. Another way of saying this is that these properties belong to the experience of having certain brain activity.

Of course, if you were to somehow travel around inside a conscious person’s brain, you wouldn’t see any redness or taste any sweetness. Nor would you find any movie screens or loudspeakers. The most you’d observe would be nerve cells, electrical impulses and chemical reactions with their own distinctive properties. You certainly wouldn’t detect the person’s phenomenal field as the person experiences it.

But if enough of those nerve cells, electrical impulses and chemical reactions are functional, a phenomenal field is present. There is consciousness occurring in there with its various properties, by virtue of the fact that having certain patterns of neural activation is enough for consciousness to occur. (As far as we know, it’s also necessary for consciousness to occur.)

Does this mean that we are only conscious of what’s going on in our brains? In one sense, yes, because that’s where the physical phenomenon of consciousness takes place. In another sense, however, and the most important sense, no, not at all. It’s reasonable to believe that consciousness evolved to help us make our way in the world, partly by representing the world to us. Our conscious experience of the world is damned good, in fact phenomenally good, when you think about it.

In fact, it’s so good that we don’t ordinarily have to think about it at all. We just use it to get around, rather like we use maps, photographs, recordings and other representations. Someone shows you a picture of Miami and asks if you’ve ever been there. Do you say “Yes” or “No” or “What do you mean? Have I ever been in that photograph in your hand?” If you’re not being a smart ass, you’ll answer “Yes” or “No”, because that’s how representations work.

In similar fashion, if someone asks you if you want the banana lying on the table, do you say “Yes” or “No” or “What do you mean? Do I want the portion of my visual field that is mostly yellow with a little bit of brown and green?” Saying “Yes” or “No” is the natural way to respond. It’s true that you can’t keep your consciousness in your glove compartment or put it on Facebook. Plus, your consciousness is what makes it possible to use those other kinds of representations. Consciousness doesn’t represent the world in the same way that maps and photographs do. But in addition to helping us think about the world, remember the past and imagine the future, consciousness also helps us observe and navigate the world, like less simple representations do. 

So that’s what I think about consciousness. Understanding how or why consciousness happens in human and animal brains is a major challenge for scientists who study brains, but it isn’t “the hard problem” most philosophers make it out to be.o-142765670-facebook

The Data From All the Senses, Part 2 (Lengthy)

When I refer to “sense data”, I mean information that’s conveyed in one of several ways, either through one of our many senses (of which there are more than the five Aristotle counted), or by whatever other means information makes its way into our stream of consciousness (for example, the introspection that allows us to carry on inner soliloquies). Philosophers sometimes use the term “qualia” to refer to “the introspectively accessible, phenomenal aspects of our mental lives”, but “sense data” emphasizes the informational aspect of our experience. I also think it’s appropriate to think of our conscious experience as a whole. The term “data”, understood as a collective noun, emphasizes what’s often called “the unity of consciousness”.

A term that could be used is in place of “sense data” is “sensorium”. Wikipedia cites the Oxford English Dictionary:

A sensorium is the sum of an organism’s perception … where it experiences and interprets the environments within which it lives…. In medical, psychological, and physiological discourse it has come to refer to the total character of the unique and changing sensory environments perceived by individuals. These include the sensation, perception, and interpretation of information about the world around us by using faculties of the mind such as senses, phenomenal and psychological perception, cognition and intelligence.

As David Chalmers put it in the article I quoted a few days ago: “What unites all of these states is that there is something it is like to be in them. All of them are states of experience.”

So what is sense data? From what is ordinarily called the “mental” point of view, sense data is information expressed as sights, sounds, smells, feelings, thoughts and so on. Although a computer can run a program perfectly well with one source of information (the data stored as tiny magnetic regions on a hard drive, for example), creatures like us need more. We require lots of information about the world in order to survive and it’s beneficial to collect that information in more than one way (echolocation would be especially handy at night). 

Hence, we evolved with various capacities for collecting information about the world inside and outside our bodies. If the information we collect is accurate, it will generally allows us to maneuver successfully and avoid difficulties. If it’s garbled, incomplete, hard to understand, illusory or even hallucinatory, it will tend to be less helpful.

From what is ordinarily called the “physical” perspective, however, sense data is activity in our brains. Scientists, of course, can only detect what’s happening in our brains up to a point, since the technology is so new. We, however, have a front row seat, metaphorically speaking. In fact, we each have a metaphorical theater to ourselves. We each experience some of the activity in our brains as sense data, i.e. sights, sounds, smells, feelings, thoughts and otherwise. Nobody understands how this works yet – how or why particular kinds of activity are experienced in particular ways – but that seems to be only a matter of time.

Among professional philosophers, the idea that sense data or conscious experience is brain activity is controversial, although not so much among scientists who study the brain. The so-called “identity theory” has been debated for decades and various alternatives have been offered. Nevertheless, it still seems to me that mental activity is brain activity, somewhat like heat is the motion of atoms or molecules, a cloud is water vapor and a squirrel is a collection of cells. 

One big objection to the identity theory that seems very wrong is that it leaves no room for minds or mental activity. Many philosophers used to believe that the mind is a mental substance that’s somehow attached to the physical substance of the body (and that made sense if a person’s mind or soul was supposed to float away post mortem). Very few philosophers think that today. Yet there are still those who believe that mental properties are very different from physical properties. Property dualism, in particular, is the idea that consciousness is a fundamental property not reducible to physical properties.

I don’t see any good reason to believe that. The simple, most plausible explanation for why so-called mental events or properties seem different from so-called physical events or properties is this: when we’re conscious, we experience some physical events in our brains as mental events (what I’m calling “sense data”), but we never experience other physical events, either in our bodies or outside them, in the same way. The traditional way of describing this distinction is to say that we have direct experience of what’s happening in our conscious minds and indirect experience (via our eyes and ears, for example) of everything else. 

Consider what we know about perception and feelings like pain or hunger. Stimuli of various kinds come in contact with specialized cells in the body. Electrical impulses make their way via the nervous system to the brain. A tiny number of these impulses are combined with the brain’s own contributions, resulting in conscious experience. It’s the activity in the brain itself that ultimately counts.

You really could be a brain in a vat and have a vivid mental life, assuming the technology existed to allow your brain to receive the necessary stimuli (and thus the necessary information to process) and to react accordingly (by seeking new stimuli, for example, as in “Hey, what’s that noise over there?”). Using the traditional terminology, It’s the end product (the sense data) that you are “directly” aware of. So long as that information kept arriving and your brain could react appropriately, your world would seem the same.

It’s the things that information is about, whether it’s the sunburn on your back, a band playing in the park or your daughter’s first day at school, that we are “indirectly” aware of (again using the standard terminology). But all of it is (or was or will be) physical stuff, whether it’s the band in the park, the electrical stimuli or the brain’s own activity. It’s all ultimately composed of things like quarks and bosons (and maybe some dark matter or dark energy, whatever those are).

But the direct vs. indirect distinction can be misleading in at least two ways. First, calling our awareness of things outside our brains “indirect” suggests that there could be a more direct way of being aware of such things. But how could that possibly be? How could I possibly be more aware of the chair I’m sitting in than by sitting in it, looking at it, measuring it, touching it and so on? Experiencing something outside of us isn’t and cannot be the same as experiencing the brain activity that’s part of us. Nevertheless, using our senses to gain knowledge about such things is the ideal, most direct way there could possibly be.

Second, saying that we are directly aware of sense data may suggest that our awareness is complete. It’s sometimes said that we have “privileged access” to our sense data. That’s certainly true, since nobody else has the same access to our sense data that we do. Similarly, the Stanford Encyclopedia article on sense data lists this as the third defining feature of traditional sense data theories: “Sense data [has] the properties that perceptually appear to us”. That’s usually understood to mean that we can’t be mistaken about what our sense data is. We may interpret our sense data incorrectly, but if you have blue sense data, your sense data is definitely blue, even if the thing your sense data is about (the wall in front of you, for example) isn’t blue at all. It could be a different color, as we usually describe such things. In reality, it’s got no “color” (the blueness you actually see) in itself at all. 

This doesn’t mean that we can always accurately describe what our sense data is or even know what we’re sensing. Data, after all, is sometimes vague, incomplete, too complex to understand and even inconsistent. (Imagine seeing an object directly in front of you that isn’t there when you try to touch it.) It’s reasonable to say that sense data always has the properties that perceptually appear to us, so long as we don’t take that to mean we are always clear about what those properties are.

The most popular objection to sense data theories is that they break the link between us and the external world. If we’re only aware of sense data, how do we know that anything outside our own minds even exists? How do we know that there is a physical world at all? Or perhaps you and I are like Keanu Reeves before he was unplugged.

Given the sense data I’ve had over the years and am still having, I’m very sure that there is a physical world outside my mind that contains New York City, our cat, Rice Krispies and aluminum siding. But am I absolutely, completely, 100% certain beyond any doubt whatsoever? Not really. I could get an extremely, extremely big surprise one day.

But so what? I’m not absolutely, completely, 100% certain that the world wasn’t created 10 seconds ago, with geological strata and historical records in place and all of us enjoying false memories of years gone by. Being able to conceive of a very different world doesn’t make that very different world plausible. Philosophers (some of them) are paid to worry about these things, and many have tried to prove beyond any possible doubt things we and they already know to be true. But the quest for absolute certainty on this or almost any other topic is a waste of time. It’s impossible to achieve and wouldn’t be of any use if it was.

In conclusion, I should mention that, in a 2009 survey of philosophy professors, graduate students and others who follow academic philosophy, only 19% of the respondents accepted or leaned toward “sense-datum theory” or “qualia theory” in the philosophy of perception. However, applying simple labels to philosophical theories is extraordinarily difficult. The most popular answer was “other” with 43%, but coming in second was “representationalism” with 26%. Another article in the Stanford Encyclopedia describes representationalism or representative realism as follows:

… our immediately experienced sense-data, together with the further beliefs that we arrive at on the basis of them, constitute a representation or depiction of an independent realm of material objects — one that we are, according to the representationalist, justified in believing to be true.

I couldn’t (and didn’t) say it better myself.

PS — It’s very difficult to contract Ebola in a country with a decent public health system, so please don’t worry. It’s not spread like a cold or the flu. If you’re in a country with a poor public health system and people are getting the disease, please don’t expose yourself to the bodily fluids of someone who has a high fever, body aches, etc. You can only get it from the bodily fluids of someone who already has symptoms.

A Guide to Reality, Part 12

Chapter 7 of Alex Rosenberg’s The Atheist’s Guide to Reality is called “Never Let Your Conscious Be Your Guide”. A more grammatical title would have been “Never Let Consciousness Be Your Guide”. A longer but more accurate title would have been “Never Let Introspection Be Your Guide to What’s Happening in Your Mind”, because that’s the actual theme of the chapter: “Scientism requires that we give up everything introspection tells us about the mind” [147].

As he often does, Rosenberg overstates his case, apparently for rhetorical effect. After all, is it really true that introspection is a completely unreliable guide to what’s going on in our minds?

He offers as evidence three kinds of phenomena. The first is “blindsight”. Researchers have discovered that people with certain kinds of brain damage can perceive features of the world without being conscious of what they’re perceiving. For example, a person with a particular kind of damage to the visual cortex, who denies seeing anything at all, can “see” colors and shapes and even the expressions on other people’s faces. If asked whether they see something, they answer “no”, but forced to guess, they give the correct answer. Here, then, is a case in which conscious introspection, which indicates that I don’t see anything, is unreliable, because I really do.

Rosenberg’s second piece of evidence concerns our common belief that we have free will. Most of us are quite convinced that we make conscious decisions that result in freely-chosen actions all the time. However, experiments suggest that when we decide to perform a random action like moving a finger a certain way, the physiological process that will inevitably lead to the action taking place is underway before we’re aware of our decision to perform the action. 

The most interesting case he cites is one in which a neuroscientist stimulates a subject’s brain, causing the subject’s finger or wrist to move but also causing the subject, milliseconds later, to claim that the motion resulted from the subject’s conscious decision.The interpretation of these findings and their relevance to the free will problem are controversial, but they do suggest that conscious decision-making may not be as important in making decisions as we think it is.

Finally, Rosenberg argues that the existence of optical illusions shows that consciousness is unreliable. We interpret visual stimuli according to unconscious rules of thumb (mixed metaphor). These rules of thumb, which are probably the combined product of human evolution and our own experience, often mislead us. The circles in the diagram below look different but really aren’t, so here’s another case, according to Rosenberg, in which we shouldn’t let consciousness be our guide. (The book includes some interesting illustrations from the Purves Lab, which are available here.)

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Chapter 7 is relatively brief, because in this chapter Rosenberg is laying the groundwork for an especially counterintuitive idea he’s going to discuss in the next chapter (that we don’t actually think “about” anything at all). For now, here’s his conclusion:

We have seen that consciousness can’t be trusted to be right about the most basic things: the alleged need for visual experiences to see colors and shapes, the supposed role of conscious decisions in bringing about our actions, even the idea that we [see the world as it is]. If it can be wrong about these things, it can be wrong about almost everything it tells us about ourselves and our minds [162].

An important thing to note regarding Rosenberg’s argument is that he isn’t really claiming that conscious sense perception is completely unreliable (at least that’s not what I think he’s claiming). Although he denies that colors, for example, are mind-independent properties, he clearly believes that we do learn about the world using our eyes and ears. Otherwise, it would be odd to offer evidence that a blind person can perceive the “correct” color of an orange and that optical illusions are illusory (compared to what?). It would also be difficult to explain why most of us navigate the world better when our eyes are open and we’re not wearing headphones.

His principal thesis in this chapter is that certain conclusions we naturally draw from introspection (“the examination or observation of one’s own mental and emotional processes”) are mistaken. Specifically, it’s natural for us to assume that we need to be conscious in order to perceive certain features of the world, that our choices clearly determine our actions, and that (prior to being let in on the secret) we can always tell whether two lines are the same length or two circles are the same color just by looking.

I think Rosenberg is wrong, however, when he concludes that introspection can’t be trusted about “the most basic things”. What are the most basic conclusions we can draw from introspection? I’m not sure about that, but some natural conclusions seem more basic than the ones Rosenberg criticizes.

For example, we are better at perceiving features of the world when we’re relatively conscious (like when we’re awake) than when we’re relatively unconscious (like when we’re asleep). Some people see and hear better than others. Sight is usually reliable, even though there are occasional optical illusions. And when we feel angry or sad, we are generally angry or sad. It’s just wrong to think that introspection is always wrong about the most basic things.

I won’t offer a more basic conclusion about free will, except to say that conscious deliberation seems to help in making some decisions (whether to enroll at a college, get married or buy a house, for example) – whatever the underlying physiological processes are. Rosenberg may be right that conscious decisions are always the aftermath of unconscious decisions. We never really know what decision we’re going to make until it starts to “feel” like the right decision or we actually do something. Maybe our brains always do the necessary work unconsciously right before we discover what we’ve decided.

Coming up (sooner or later), part 13 of “A Guide to Reality”: Is it true that the brain does everything without thinking about anything at all?