Dualism

One view of the mind says that connected to every living body--or perhaps only to living bodies that are able to think and be self-conscious--is a separate, non-physical thing we can call a soul. The body is one thing, a physical thing; and the soul is another, independent and non-physical thing. 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.

The view of the mind is called dualism, because its proponents think that there are two kinds of things: physical things and mental things (souls). The souls are not made up of physical parts. In principle, they can exist independently of any bodies or other physical things. To think or have feelings requires you to have one of these souls.

So the dualist thinks there are two kinds of things. Other theorists think there is only one kind of thing.

?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."

In the Mind and Brain dialogue, the character Mary is a materialist. She says that there are no souls, and that instead, the mind is just the brain. When ordinary people talk about souls, she thinks, they usually just mean to be talking about the mind, and on her view 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.

We'll build up to this gradually.

First consider the following examples.

Claire has a sharp knife. Claire has a sharp wit.

Once you climb the steep cliffs on this side, you'll find a gentle slope down to the plain. Despite his harsh words, Mike has a gentle touch.

Let's look first at the first column. It says that there is this thing, a knife, that Claire possesses. And there is a thing, a slope, on the other side of the cliff.

But now in the second column, when we talk about a sharp wit and a gentle touch, we don't seem to be talking about things in the same way. Well, in one sense they are things. I can say, "There's one thing I really like about her, that's her sharp wit." But Claire's wit doesn't seem to be a thing in the same robust, full-blooded way that a knife and a slope are things. Philosophers use the term substance when they're talking about things in this robust, full-blooded way. Knives and slopes are substances, but wits and touches aren't.

Substances don't always have to be solid things; they don't have to be things that you can touch and feel. A cloud is a substance. A campfire is a substance. So is the oxygen it consumes. If there are any ghosts flitting about the campfire, then they would be things, too, in the full-blooded sense in which knives and campfires and oxygen are things. Unlike the other things, though, ghosts would be non-physical substances.

There seems to be some intuitive difference between: knives, slopes, clouds, fires, oxygen, and ghosts, on the one hand, and wits and touches, on the other. The former seem to be "things" in a robust and full-blooded sense in which the latter don't. Philosophers put this by saying that only the former things count as substances.

Here's another example. Suppose you tell me, "We're going to take a hike." Wouldn't it be absurd if I responded, "Don't take the last one! I was saving it for this weekend!" Why would that be absurd? It's because a hike isn't really 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.

What do hikes, wits, and touches all have in common? 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