Dualism vs. Materialism

sam brown, explodingdog

There's also a more narrow use of the term "soul", where only living things that are able to think and be conscious have souls. For the rest of this class, we'll be using "soul" in this more narrow sense.

It's controversial whether there are any souls, in either of the senses. We already considered objections to vitalism. Let me explain the controversy about whether even thinking things have souls.

One view of the mind says that connected to every living body that is able to think and be self-conscious is a separate, non-physical substance, its soul. The body is one thing, a physical thing; and the soul is another, independent and non-physical substance. The soul is what does all the thinking. It's not made up of physical parts. While the body is alive, the soul is connected to it, but it's possible for the soul to go on existing even after the body is destroyed. In principle, souls can exist independently of any bodies or other physical things.

This view of the mind is called dualism, because its proponents say there are two kinds of substances: on the one hand, physical substances, including human bodies; and on the other hand, non-physical souls.

Other theorists say there is only one kind of substance:

• The materialist or physicalist says that the only things there are are all material or physical things. Materialism was originally the view that everything is made of matter. (That's why it's called "materialism.") Nowadays, though, philosophers have broadened the meaning of this term, so that you can still be a materialist even if you believe in gravitational fields, curves in space-time, and other things which are clearly not matter. Basically, the materialist believes in whatever our best physics tells us about.
• The idealist says that there are no material things, there are only minds and thoughts and experiences. There is no mind-independent, physical table here; there are only certain experiences I have as if there's a table.

  You've probably all heard the following philosophical problem: Suppose a tree falls in the forest but there's no one there to hear it. Does it make a sound?

  One answer says:

  Yes, it does make a sound: because a sound is a physical phenomena, perhaps some wave patterns in the air. Those wave patterns can exist even if no one's there to hear them.

  The other answer says:

  No, a sound is essentially something that has to be experienced. If no one hears it, then it can't be a sound.

  You might say the same thing about colors: if no one sees them, then they can't really exist.

  The idealist is someone who holds that kind of view not just about sounds and colors, but about everything: about tables, and elephants and even their own bodies. If they're not experienced then they don't really exist. Really nothing can exist except for minds and the thoughts and experiences that those minds have.

In this class we won't be talking very much about idealists. We'll be concentrating on the debate between dualists and materialists. So we'll take it for granted that things like tables are real, mind-independent things made up of matter. The question we're interested in is whether, in addition to material things like tables and elephants, there are also these non-physical things called "souls."

A materialist will sometimes express herself like this: there are no souls, instead the mind is just the brain. When ordinary people in the street talk about "souls", they usually just mean to be talking about the mind, and really that's just the brain. Not some non-physical thing like the dualist has in mind.

So that's one way to be a materialist. You say that the mind is not a non-physical thing, a soul, but rather that it's a physical thing, the brain.

But I want us to think about a more subtle kind of materialism, which says that the mind is not really a kind of thing at all--not a spiritual thing and not a physical thing, either.

Remember our discussion of substances from last time.

Consider another example. Suppose you tell me, "We're going to take a hike." If I responded, "Don't take the last one! I was saving it for this weekend!" that would just be a bad joke. Why? I'm talking as though hikes were substances, and as though there might be just one left, which you might take. But a hike isn't a substance. Rather, it's more a process or activity. It's something that people do, not a thing that people can "take" in the way they can take a ticket.

Recall:

What do hikes have in common with wits and touches? They have it in common that we use nouns to talk about them, but we don't really think there are any substances or things, in the full-blooded sense, corresponding to them. On a hike, the only substances are:

• the hikers
• their clothes
• the dirt path they're walking on
• the oxygen they're breathing
• the sweat on their skin

There's not some further, additional substance, the hike.

Now let's consider some more examples:

How do the examples in the third column work?

Remember, the dualist says that the mind is a kind of substance, a special kind of non-physical substance. We saw that one way to be a materialist is to say that the mind is rather a physical thing or substance, like the brain. But maybe the best thing to say is that talk of "having a sharp mind" or "a gentle spirit" is like talk of hikes, wits, and touches. There's not really some additional thing or substance corresponding to these words. If we take this line, we can say that a person "has a mind," but we don't mean by that that there's some additional thing that the person has: neither a physical thing nor a non-physical thing. Rather, to say that a person "has a mind" is just to say that their brain and body can do certain things: they can think, they can have experiences, they can make choices, and so on. When your brain and body can do those things, we say that you "have a mind." Just as, when your brain and body do certain other things, we say that you're "taking a hike." There's not some additional thing or substance, a hike, that you're taking. It's just a way of talking.

I will count this view of the mind as a materialist view, because it too says that the only substances there are are material or physical substances. Like tables and rocks and human brains and bodies. There aren't any extra, non-physical substances in addition to all that.

Now, I said that for the materialist, to say that you have a mind is just to say that your brain and body can do certain things. They can think, they can have experiences, they can make choices, and so on.

The dualist doesn't think that brains and bodies can do any of those things. According to the dualist, it's only souls which are able to think, have experiences, and so on. Physical things like your brain and your body can't think and have experiences. Imagine there are all these chunks of dead, unfeeling matter. According to the dualist, it's only after a soul comes along and "inhabits" or attaches to the matter, that there can be real thoughts and feelings. Without a soul, there is no thinking or consciousness or any sort of mental life going on.

There are some things that the dualist and the materialist agree on. They agree that there are these special kinds of states and processes that only thinking, feeling creatures can have. Some examples are:

• pains
• itches
• the experience of seeing red
• hearing yourself think
• wanting to go on vacation
• remembering that Henry VIII was an English king

and so on.

The materialist and the dualist agree that only certain sorts of creatures are able to have thoughts, experiences, and other mental states. Whenever a creature is able to have these mental states, we say that the creature "has a mind." So if you have a belief, or experience any emotions, or have memories, then you "have a mind," on everyone's view. Both the dualist and the materialist agree that we "have minds." Having a mind is what distinguishes you from things like rocks and plants. You can think, and you are conscious. But a rock and a plant aren't conscious, and can't think. They don't have any mental life. They don't have minds.

What the dualist and the materialist disagree about is what "having a mind" amounts to. The dualist thinks that in order to have a mind, you quite literally have to have some thing, a soul, connected to your body. The soul is what really does the thinking and feeling. If you have a toothache, it's really your soul that feels it. If you think about Maine, it's really your soul that does the thinking. "Having a mind" is having one of these non-physical things, a soul.

According to the materialist, though, that's not what "having a mind" consists in. According to the materialist, all there is to people is their physical body, their brain, the electrical patterns in their brain, and so on. If you put these together in the right way, the materialist thinks, you'll get beliefs, and emotions, and memories, and so on. The brain and the body are able to have thoughts and experiences all by themselves, because of the complicated way that they're built, without any help from a non-physical soul. The only substances involved are your physical brain and body. When they are configured in the right way, thoughts and feelings take place, and then we say that you "have a mind."

Realism, Reductionism, Error-Theory

In a philosopher's vocabulary, a realist about Xs is someone who believes that Xs really exist, that they aren't mere fictions. Realists about Xs also think that Xs aren't radically different from the sort of thing we thought they were all along.

For example, a realist about the external world is someone who believes that there really are chairs and tables and oaken chests; that these are real things in the world and that they're not just ideas in our mind, or constructions out of our experiences. A realist about nations thinks that things like France and the United States really do exist. An opposing view would say that nations don't really exist, or that they're just a kind of "social construction." That is a non-realist view about nations.

The issue of realism doesn't just apply to things. It also applies to properties. For instance, I am a realist about wealth. I believe that some people really are rich, and other people really are poor. Being a realist means believing that people really do have those properties. It doesn't mean you think that people who are rich will always be rich, or that you think they deserve to be rich, or anything like that. Realism about the property of being rich just says that some people really do, as a matter of fact, and at some time, possess that property.

A reductionist about certain things or properties is someone who thinks that facts about those things or properties can be reduced to, or explained away in terms of, facts about something else. For instance, most of us believe that biology reduces to chemistry. There are no distinctive, brute biological facts. It's really all just chemistry. Perhaps facts about nations can be reduced to facts about certain people, and their actions, and what laws they enact. Facts about wealth might also be reducible in a similar way.

Sometimes reductionists count as realists, and sometimes they don't. It depends on what they're reducing things to. It's hard to come up with any general rule that tells you for all cases whether a given reductionist is a realist or not. If you think that facts about tables reduce to facts about atoms and electrons, then philosophers will still count you as a realist about tables. If you think that facts about tables reduce to facts about our ideas and experiences, then you're not a realist about tables. That's the view I called idealism.

Remember, the idealist thinks that the only things there are in the world are limited to, or in some way dependent on, minds and mental phenomena. Idealism is one kind of reductionist view about tables, but since on the idealist's view, tables turn out to be radically different sorts of things than we ordinarily took them to be, we don't count this as a realist view.

So one non-realist view is idealism. Another non-realist view is what we call error-theory. Error-theorists about Xs simply say that there are no Xs. For instance:

There are no demons. Nor is there any such thing as "being cursed." Anyone who thinks that there are demons, or that some people are "cursed," is making an error.

• Sometimes the error-theorists tell us that we ought to just eliminate the notion in question, and no longer talk about it. Other times they might say that the notion serves a useful practical function, and that we can retain it as a useful pretense, so long as we recognize that really there are no such things. For instance, some philosophers think that modern science has shown us that there is no such thing as color. On their view, there are photons and reflectance patterns and neurons firing in the brain, but there is no such thing as color. Most of these philosophers are perfectly happy to let Kodak and Fuji go on selling "color film." They don't say that we have to get rid of the word "color." That word serves many useful functions. They just think that really, strictly speaking, we should recognize that there are only photons and neurons firing and so on, and no real colors.