Philosophy

6

LECTURE: The mind-body problem

Getting started

The organizing theme of our look at human nature this semester will be one of the classic problems of philosophy, known as the mind-body problem. What is that? To set the stage for an answer, let’s first say a little bit more about philosophy in general.

Last time I explained what philosophy is and how it relates to the sciences. Now, like science, philosophy has a number of sub-disciplines within it – fields that apply philosophical analysis to specific subject areas. Two of the most fundamental ones, which are especially relevant to what we are going to be talking about this semester, are known as metaphysics and epistemology. Let’s consider these in order:

metaphysics: the rational investigation of the general structure of reality and of the ultimate causes of things

Metaphysics is, you might say, the most philosophical of all the sub-disciplines of philosophy – the one that deals with the most fundamental issues of all, and from which all the other sub-disciplines in philosophy (and indeed, all other fields of study of any kind) borrow their basic assumptions. What sort of things make up reality, and why? This quest for the most general description of what there is and the most ultimate explanation of why it is the way it is is characteristic of metaphysics. Then we have:

epistemology: the theory of knowledge: its nature, possibility, scope, and general basis

Epistemology wants to know, first, what it is to know something (as opposed to merely believing it, conjecturing about it, and so on); second, whether we can in fact have genuine knowledge (as opposed to having to settle for mere opinion); third, whether all aspects of reality are in theory knowable by us, or whether some aspects are in principle closed off; and fourth, what the ultimate source of knowledge is. (Does all knowledge come from the senses? From pure reason? From some mix of the two?)

This meme may be dead, but metaphysics isn’t

In short, metaphysics is concerned with what reality is like, and epistemology is concerned with how we come to know what reality is like. And both are relevant to the study of human nature. What is a human being? Something purely material, or a mixture of matter and spirit, body and soul? And how does the human mind come to know anything outside itself?

Mind and matter

This brings us, then, to the specific metaphysical issue that will, as I say, provide the organizing theme for the semester. We can state it as follows:

The mind-body problem: What is the metaphysical relationship between mental phenomena (e.g. thoughts and experiences) and physical phenomena (e.g. neural processes and bodily behavior)? Are they identical? Are they distinct but causally related? How could they possibly be either?

Consider that there are two basic aspects of human nature. On the one hand, there are thoughts, experiences, sensations, memories, moods, emotions and the like – mental phenomena, things going on in our minds. On the other hand, there are bodily movements, firing patterns in the neurons that make up the brain and nervous system, glandular secretions, and so on – physical phenomena, things going on in our bodies.

Now, what is the connection between them? Should we say that the first are identical to the second – that thoughts and experiences are the very same thing as, or nothing but, neurons firing in the brain, chemical secretions, etc.? That would be the view known as materialism – the view that mind is essentially reducible to matter. On this view, the mind is just the brain, just one physical object among others.

Or should we say that mind and matter are distinct – that the mind is not reducible to matter, that it is something over and above matter, and indeed perhaps can even exist apart from matter (as a disembodied soul, say)? Should we say that the mind is a non-physical entity that has a cause-and-effect relation to what goes on in the brain, but is not the same thing as the brain? This is the view known as dualism – the view that human beings have a dual nature, being made up of something material and something non-material, body and soul.

When you’ve got to go read a PHIL 8 lecture

It turns out, though, that either answer we give raises serious problems. For one thing, it turns out to be very difficult to reduce mind to matter. There are certain features of the mind that make it seem impossible that the mind could be the same thing as the brain, for example. On the other hand, if we say that mind and matter are distinct things but somehow interact causally, that turns out to be problematic as well. How something physical and something entirely non-physical could get in any sort of cause-and-effect relationship ends up being mysterious too.

So, both materialism and dualism end up facing serious objections. That’s why there’s a mind-body problem. Solving the problem would require showing either how materialism can answer the objections facing it, or how dualism can answer the objections facing it, or how some third alternative might work.

Three problematic aspects of the mind

But what exactly is it about the mind that makes it difficult to explain its relation to the body? There are three aspects in particular that are notoriously difficult to explain in purely materialistic terms. Of course, materialists would say that these problems can be gotten around. But the point is that these three aspects at least seem at first glance difficult for materialism to account for, so that the materialist has to come up with some way of showing that they really are physical after all, despite appearing to be non-physical. These three aspects are as follows:

1. The qualia problem:

The first issue concerns an aspect of the mind that philosophers refer to by the technical term “quale” (where “quale” is singular and “qualia” is the plural form of the term). Though the word is technical, what it refers to is something that couldn’t be more familiar. We can define it as follows:

Qualia: the subjective or “first-person” aspects of a conscious experience, in virtue of which there is “something it is like” to have the experience (e.g. the way pain feels, the way red looks, the way a rose smells)

Consider what happens when you slam your hand in a drawer. There are, first of all, the damage to the hand, the scream and the tears you let out, the reflex response of pulling your hand back, the activity in the nervous system, etc., all of which are observable by other people. But second, there is the feel of the pain. And that is directly knowable only to you, from within your own consciousness. No one else can literally feel your pain, much less see, hear, or touch it.

This “feel” is what philosophers would call the quale of the pain (as in the word “quality”). It is “subjective” or “first-person” in the sense that only the subject of the experience, the one undergoing it, has direct access to it from the first-person point of view of the self, the “I,” or the ego. Everyone else, looking at the situation from the outside or “third-person” point of view, can know only of the causes of the pain (the damage to your hand) or the effects of the pain (the screaming, crying, etc.). Again, they can’t observe the quale of the pain itself. Only you can.

Pretty much, yeah

Another example: Consider the way a red object looks to someone who is colorblind and how that differs from the way it looks to someone who is not. If you are not colorblind and you “got inside the mind” of someone who is, you might say: “Wow! Red looks very different to you from the way it does to me!” Of course, you can’t in fact see into someone else’s mind. But the way the color looks “from the inside” is the quale of the experience of seeing red.

One more example: Suppose you form a mental picture of what your mom’s face looks like, or a memory of what your favorite song sounds like. Of course, no one else can literally get inside your mind and see the image or hear the sound. If others looked into your brain, they wouldn’t see a little picture of your mom there, and if they put their ears next to your skull, they wouldn’t hear the song “playing” inside your mind. The appearance, sound, and feel of such mental imagery would be further examples of qualia.

Now, there are a couple of ways that qualia pose problems for materialist attempts to reduce consciousness to some physical feature of the brain:

First problem qualia pose for materialism: (1) Physical things, including your brain and everything going on in it, are equally directly knowable to every observer. Anyone could in theory observe what’s going on in your brain, just like anyone could look inside a drawer or under the hood of a car. By contrast, (2) your qualia are directly knowable only to you, and no one else can observe them. So, (3) it seems to follow that qualia are not physical, because physical aspects of the brain have a feature (direct knowability to everyone) that qualia don’t have.

Second problem qualia pose for materialism: At least as usually interpreted, physics seems to tell us that color, odor, sound, taste, heat, cold, etc. as common sense understands them don’t really exist in the material world. The physical world is instead made up of colorless, soundless, odorless, etc. particles in motion. The colors we see, sounds we hear, etc. exist only in our conscious experience of the world, as qualia. We project onto the world colors, sounds, etc. when in reality, “out there” there are really only colorless, soundless, etc. particles.

The problem this poses for materialism is this: If colors, sounds, and other qualia don’t exist in matter, that means they don’t exist in the brain, which is made up of matter. Yet these qualia do exist in the mind. So, if qualia exist in the mind but not in the brain, then it seems to follow that the mind is not the brain.

Can the materialist get around the problem?

Now, materialists would respond that though it does seem as if qualia cannot be physical, this is an illusion. We’ll look later at how materialists have tried to explain various aspects of the mind. The point for the moment is just that the qualia problem at least poses one hurdle that any attempt to explain the mind has to get over.

2. The problem of intentionality:

“Intentionality” is another technical philosopher’s term for something that is extremely familiar. It comes from a Latin word meaning “to aim at” or “to point at.” We can define it as follows:

intentionality: the meaning, directedness, or “aboutness” of thoughts, language, etc.

When you think about cats, there is something going on in you that is about cats, that aims at or points to cats, that is directed at cats. This is analogous to the way that the word “cat” is about, means, aims, or points at cats. In this way, the word is different from a random set of letters like “sghedqapr” or a random squiggle like: . The random letters and the squiggle are not about anything, they don’t mean anything. They’re just random, meaningless marks. They have no intentionality in the relevant sense, whereas the word “cat” and your thought about cats do have intentionality. So too do other words and thoughts.

Now, the meaning or intentionality that a word like “cat” has is not built into it, but derives from custom or convention. Considered by themselves, the string of letters “c-a-t” is as meaningless as the random letters or squiggle above. So too is the sound we make when we say the word “cat.” By itself it has no more meaning than a random sound like “shmat” does. Here too, the meaning or intentionality of the word derives from custom or convention. In particular, it derives from the thoughts of language users, who form these customs or conventions of using certain shapes and sounds to convey meaning.

Now, physical things in general seem to be like random letters and squiggles. Shapes, ink marks, color patterns, lines, etc. – considered just by themselves they seem to have no meaning or intentionality at all. By contrast, thoughts seem to have intentionality in a “built in” way. You could say that having meaning or intentionality is just what it is to be a thought in the first place.

A thought aims or points toward its object

The problem this poses for materialism is this: If nothing physical has any built-in meaning or intentionality, but thoughts do have built-in meaning or intentionality, then it seems to follow that thoughts cannot be physical things.

Here too, the materialist would say that though this seems to be the case, it is an illusion and intentionality can be given a materialist explanation. We’ll see later on some ways that materialists have tried to get around the problem. The point for the moment is just to note that it is a problem that has to be addressed.

3. The problem of rationality:

Finally, we have the problem that rationality poses for materialist attempts to explain the mind.

Here we can define the notion as follows:

rationality: the ability to grasp abstract concepts, to put them together into complete thoughts, and to reason from one thought to another in accordance with the laws of logic

Consider the way that you can not only perceive this or that individual man, but can form the general concept or idea of being a man. You can not only perceive this or that individual mortal thing, but you can form the abstract concept of being mortal. And so on. Furthermore, you can put these concepts together into the complete thought: All men are mortal. And beyond that, you can reason logically from the thought that all men are mortal and the further thought that Socrates is a man, to the conclusion that Socrates is mortal.

Having these capacities is what is involved in having reason or rationality. And it turns out to be difficult to explain this aspect of the mind too in materialist terms.

You might think that machines – like computers or calculators – are obvious examples of physical things that possess rationality. After all, they can do things like solve complicated mathematical problems, right? But it’s not as simple as that. After all, calculators and the like don’t add, subtract, etc. on their own. They do what they do because we made them to do that. In fact, strictly speaking, it isn’t really these machines that add, subtract, etc. but we who do so, using these devices as aids to doing these things. So, more would need to be said in order for the appeal to computers and the like to show how rationality can be purely physical.

Do you think this thing can think?

Spelling out the problem of rationality in detail is a bit more involved, though, and we’ll get to that soon enough. For now we can note that the mind-body problem is ultimately the problem of explaining how qualia, intentionality, and rationality are related to physical processes in the brain and body. Is the dualist correct to say these things are non-physical? Is the materialist correct in claiming that these features can, at the end of the day, be show to be purely physical after all? Or is some third alternative the right view? We’ll be looking at the arguments for the different sides of this issue.

OK, that’s enough for now! Here are some optional YouTube videos, one on the mind-body problem in general, and one on the aspect of the mind-body problem having to do with qualia and conscious experience:

Closer to Truth on Solutions to the Mind-Body Problem:

https://www.youtube.com/watch?v=yp193r6i7qk

David Chalmers on the Hard Problem of Consciousness:

https://www.youtube.com/watch?v=C5DfnIjZPGw