sam brown, explodingdog
We’re going to be setting up a debate between two broad camps of views about how minds and bodies are related. One camp is called substance dualism, or dualism for short. (Later we’ll talk more briefly about some other kinds of dualism.) The other camp is called materialism or physicalism.
The quick and short explanation of how these views differ is that the substance dualist says having a mind consists in having a soul, and the soul is what fundamentally does the thinking and feeling. The materialist or physicalist on the other hand denies that there are any souls, or anything else except the kind of things that physics investigates. On their view, having a mind is just something that happens when physical stuff is arranged in the right ways.
To go beyond that quick and short explanation, we need to get a better understanding of what these philosophers mean by words like “substance”, “dualism”, “soul”, and some other concepts.
Unfortunately, things here are somewhat messy. In other philosophy classes, like a metaphysics or philosopy of science class, you might investigate some of these notions and the debates around them more closely. For our present purposes, though, it’ll be enough to get a rough handle on how philosophers understand these notions.
Ontology is the part of philosophy that studies/argues about what exists. It’s a subpart of metaphysics, which studies/argues about the basic structure and furniture of reality. Not just concrete physical reality, but also non-physical reality, if things like minds turn out to be partly non-physical, or if things like God or angels exist. And also abstract reality, if things like numbers or sets exist. Metaphysics also studies notions like time and causation and so on.
One basic division in ontology is between abstract notions, like numbers for example, and notions with some generality to them, like circles-in-general (as opposed to such-and-such a specific yellow circle on my coffee mug). Or the general notions of justice and terror. Opposed to “abstract” is concrete. This includes everything that’s specific. On some views, it would include only things that have a specific location in space and time. But that’s not built into the meaning of “concrete”. If God exists, God would also be concrete, even if not in space and time. Concrete just means specific, not abstract. It would be a substantive, controversial claim that everything which is concrete is located in space and time. Similarly, some philosophers would say that everything abstract has something to do with our concepts or is subjective. But that again is a substantive, controversial claim. It’s not part of the meaning of “abstract.” Many philosophers think that numbers and sets objectively exist, aren’t dependent on our concepts; and they’re not confused when they say that numbers and sets are abstract.
It’s important in philosophy to keep track of what is supposed to be part of the definition of a notion like “abstract” or “concrete”, and what is instead a substantive claim about that notion, that could be intelligibly disputed by someone who isn’t changing the definition.
(If you’d like to read more about the notions of abstract and concrete, and controversies about how to define them, see Gideon Rosen’s SEP entry.)
Another basic division in ontology is between things or substances, on the one hand, and properties (or “attributes” or “qualities”) and relations, on the other. Some examples of properties are:
These examples cover a range. Some philosophers would deny that some of them (like the second) really are properties. The third example is a property that I and/or my body currently has. If we stick to Newtonian physics, it’s a property that I have just in virtue of how I am in myself, and if I were to lose that property, it would have to be because I somehow changed in myself. (I became shorter, or taller.) The fourth property is interestingly different. It might be that I lost that property because I changed in myself (I grew a lot overnight). Or it might be that I lost that property not because of anything that happened to me, but rather because of what happened to Professor Worsnip (he shrunk overnight). All of these are examples of properties I have, but the third is sometimes called an “intrinsic” and the fourth an “extrinisic” or “relational” property.
A property is something that has a single bearer or argument: the second, third, and fourth examples above are all properties that I, Professor Pryor, bear. A relation is instead something that has two or more bearers or arguments. An example might be being shorter than. Although being shorter than Professor Worsnip is a property that I have, being shorter than is a relation that I stand in to Professor Worsnip. In some cases, when A stands in a relation to B, B doesn’t need to (and sometimes can’t) stand in the same relation to A. If I’m shorter than Professor Worsnip (at this moment), he can’t also be shorter than me (at this same moment). (Again, for simplicity, I’m sticking to Newtonian physics. If you’ve studied special relativity, you’ll know what’s problematic with these examples.) In other cases, A and B can stand in the same relation to each other. For instance, I stand in the relation being part of the same department to Professor Worsnip, and he stands in the same relation to me.
There can also be relations that have more than two bearers or arguments. An example might be being intermediate in age between. I stand in that relation to Professors Worsnip and Professor Wolf.
So that’s one philosophical category, the box of properties and relations. A contrasting box is that of things or individuals or substances. These are the kinds of things that aren’t themselves properties, but instead are what fundamentally have properties. (On many views, properties and relations can also have properties. For instance, the property of being shorter than Professor Worsnip has the property of being an extrinsic property.)
In a moment, we’ll inquire further into the notion of a substance. But let’s first finish this quick and rough overview of different ontological categories that philosophers talk about.
Most philosophers recognize the boxes of substances, on the one hand, and properties and relations on the other. (Although some philosophers argue that we don’t need the substance box, and can instead explain everything using only the property box, or that plus some of the others to be discussed in a moment).
If there are substances, everyone agrees they’ll be concrete. With properties, most will say they’re abstract; but this is more controversial.
Some philosophers are satisfied with just those two (or fewer) boxes. But many think we need more boxes as well. One kind of box that’s sometimes posited is that of facts. Some philosophers will say that there’s such a thing as the fact that Professor Pryor is (currently) shorter than Professor Worsnip, and that this is neither a substance nor a property or relation. Others might accept that there is such a thing as that fact, but argue that it is a property after all (perhaps a property of the whole world?). Or maybe it shouldn’t be called a property, but it belongs in the same category or box as properties and relations. While properties have single bearers, and relations have two or more bearers, facts are the same kind of thing, they just have zero bearers. It’s not important for us to get into these debates, or decide upon any of the proposals. We’re just getting the feel of the terrain.
Terminological note: When we talk about facts, we assume that they are always true. If something isn’t true, it’s not a fact (although people could mistakenly think it’s a fact). When philosophers want to talk about things that could be true oe false, they instead use the notion of a proposition. You can think of these as something like a hypothesis or theory or statement that gets expressed with a declarative sentence.
Another kind of box that’s sometimes posited is that of events or processes. Some philosophers will distinguish between the fact that I recently joined the UNC Chapel Hill Philosophy Department, and the event of my joining the department. If events exist, they are specific concrete occurrences. There are also types of events. These are something like properties that can be had by different events. For example, there is the event-type joining a philosophy department. Since I’ve belonged to several department, there are multiple events involving me of that type. There are also events of that type where other philosophers are the agent.
That’s a type of event where something changes: one starts out not belonging to a department, and then some things change so that at the end, one now has joined the department. There are also more boring events. For instance, there’s the event of me being 70 inches tall today. I was 70 inches tall yesterday, and I’ll probably still be 70 inches tall tomorrow. So nothing changed in this respect today. But me being 70 inches tall today is still an event that some philosophers will recognize. Sometimes these kinds of things are called “states”; and some philosophers reserve the word “event” for when things have been more dynamic.
The distinction between types versus particulars or tokens is one we’ll encounter several times, and this distinction applies more generally than just to events. Another example of a token is your current laptop (assuming you have just one); whereas a type or kind of thing would be whatever model laptop you have. Many laptops can all be of the same type. (In principle, there can also be very unusual types of things that have only one example or token. Philosophers argue about whether we should admit types of things that have no examples.)
Another example often used to illustrate the distinction between types and tokens is this: How many letters are there in the word “hello”? There are five letter tokens, but only four letter types, because two of those tokens (the two “l”s) are tokens of a single type.
This type/token contrast comes up in some places in van Inwagen’s reading, and we’ll encounter it a couple of times through the semester.
Even if there are allowed to be events that aren’t located in physical space, particular events and/or states are thought to be concrete. Types of events and other things, though, are usually thought to be abstract.
Some philosophers will distinguish between properties like being beautiful or being terrified, on the one hand, and such things as beauty or terror on the other. If so, the latter kind of thing goes by different names. They would definitely be counted as abstract. The corresponding properties would also be counted as abstract by many philosophers, but not others.
This isn’t meant to be an exhaustive or in-depth accounting of different categories, but just to introduce to some of the ones that philosophers commonly work with and talk about, and to give you a rough handle on them.
Let’s get back to the category of things and/or substances.
Consider the following examples.
| Mel has a sharp knife. | Mel has a sharp wit. |
| Once you climb the steep cliffs on this side, you’ll find a gentle hillside sloping down to the plain. | Despite his harsh words, Derek has a gentle touch. |
| My cellphone has a bright light. | Persephone has a bright smile. |
Sharpness (or being sharp, if that’s different) is a property that can be had by both knives and wits, but knives and wits seem to be importantly different.
Similarly, gentleness is a property that can be had by both hillsides and touches, but hillsides and touches seem to be importantly different.
Lights and smiles also seem to be importantly different.
The notion of a substance is a philosophical tool for unpacking these differences.
Terminological note: Greek philosophers had a notion ousia, which is a form of the verb to be and is connected to our term “ontology,” that they used in a special way. This word was translated into Latin as either essentia and/or substantia. Some authors used one translation, others used the other, and some used both. English has inherited the words essence and substance. Over thousands of years and many philosophical debates, these different terms have shifted and sharpened their meaning in some ways. We will talk about “essences” next week. For now, we’re going to talk about the way the notion of “substance” is used, at least in modern and contemporary philosophy.
(“Modern philosophy” means from about 1600-1800. “Contemporary” philosiophy means from about 1900 until now.)
“Substance” is sometimes used just to mean “the stuff you’re made of”. For example, I have a statue of Frodo Baggins, and it’s made of clay. The substance this statue is made of is clay. (Some philosophers would say that the statue and the clay are one and the same thing, others wouldn’t.)
But there’s a more dominant use of “substance” in philosophy to mean something like a thing or a particular, in a robust, full-blooded sense. And this is the notion we want to work with.
Words like “wit” and “touch” and “smile” are nouns. We might call them “things” in some sense. After all, you could say, “Your knife may be sharp; but something that’s even sharper is your wit.” Or “One thing I like about you is your sharp wit.” But you may have the sense that knives and hillsides and lights are things in a deeper or more basic sense than wits and touches and smiles are. Philosophers try to capture this using the notion of substance. They might say that knives and hillsides and lights are substances, but the other things are not.
I’m afraid this notion is explained or defined in a variety of ways; and it’s not obvious or straightforward whether all the definitions are equivalent. But the kinds of things that are usually said to unpack the notion of substance are:
(If you’d like to read more about the notion of substance, and controversies about how to define it, see Howard Robinson’s SEP entry.)
These explanations themselves have parts that need explaining. What’s meant by a “fundamental” bearer of properties? What’s meant by “can in principle” and “exist on their own”? Some of this (“can in principle”) we’ll get to in later classes. But let’s try to unpack the other ideas a bit further now.
One idea here is that a knife is the kind of thing that can have properties in itself, intrinsically. The knife either is sharp or it isn’t. Whether it’s sharp might depend on what shape its edge has, but its edge is part of the knife. Once we’ve settled how the knife and its parts are, we’ve settled whether it’s sharp. The knife can also have extrinsic properties, too. It can be further away from me than my cellphone is. But it’s the kind of thing that can have properties on its own.
For Mel’s wit to be sharp, on the other hand, or for Derek’s touch to be gentle, or Persephone’s smile to be bright, these depend on other things having properties. Mel’s wit is sharp only if Mel has certain properties. And Mel is not part of Mel’s wit. For Persephone’s smile to be bright, that depends on the shape of her whole face and how it moves when she smiles. And her whole face is not part of her smile. Thus even if we count wits, and touches, and smiles, as things in some sense, they seem to depend for their existence on other things, which are more fundamental. Substances aren’t supposed to depend on anything else (except maybe their own parts).
Another example of something that’s plausibly not a substance is a particular wave that’s approaching the Wilmington coast right now. On some views, the Atlantic Ocean might be a substance. But that wave wouldn’t be. It depends for its existence on what properties the Atlantic Ocean has. From moment to moment, the wave is made up of different quantities of water as it moves through the ocean. Perhaps it also depends for its existence on the fact that the Atlantic Ocean stops at a certain point and the air above the ocean begins. It’s not clear whether the same wave could exist wholly underwater.
So the basic idea is: things like wits, touches, smiles, waves, these may be things, but they’re somehow derivative or dependent on other things. Things like knives and people and hillsides and lights and oceans are more fundamental. They are better examples of being substances.
It’s controversial what things exactly count as substances. That’s why I’ve hedged a bit and said these are “better examples” of being substances. Some philosophers don’t think there are any substances at all, just properties and/or events. But most do think there are substances. They just disagree about what the substances are. Some philosophers might say that the basic elements of physics, quarks and whatnot, are the only substances. Some philosophers might count electromagnetic fields or spacetime as substances; others wouldn’t. Many philosophers think that in addition to those microscopic substances, larger objects built out of them — like knives and people and so on — also count as substances. (Those who don’t think this argue instead that knives and people and so on are more like smiles or waves.)
Some philosophers think that in addition to to those physical substances, there are also non-physical substances. If ghosts exist, they would be examples of substances. If God exists, God would definitely be a substance. So it’s not part of the definition of the notion of substance that substances have to be physical or reside in space and time. Nor is it part of the definition of substance that substances have to be measurable or mind-independent. Many plausible examples of substances may have those properties, and some philosophers may argue for the substantive view that things which are physical and measurable are in fact the only substances that really exist. On other views, though, God is a substance that really exists, and some philosophers have even argued that God is the only substance. On other views, God is a substance, and space (or spacetime) is a substance, and everything else (that’s concrete) is just something like a ripple in, or aspect of, one of those two. But most philosophers think there are many substances.
Monists are philosophers who think there is only one kind of substance.
A radical form of this would be that philosopher who thinks there’s just one substance, period, and it’s God.
Another radical form of this would be the philosopher who thinks their own mind is the only substance.
But philosophers who think that God exists and angels exist and many human minds all exist, but nothing else, would also be monists.
All of the philosophers just mentioned think that the only kind of substances there are are mental, non-physical substances. A different way to be a monist would be to say that the only kind of substances there are are ones that physics investigates. Perhaps there are only the basic elements of physics. Or perhaps there are those plus spacetime. Or perhaps macroscopic objects like people and galaxies are also substances. There are different views one could have. But all of these count as broadly materialist or physicalist views.
They are also monists about how many different kinds of substances there are. Just one kind: on their view, though, that kind is physical substances.
Terminological note: “Materialism” was originally the view that everything is made of matter. (Hence the name.) But its usage has broadened so that now you can still be a materialist if you believe in gravitational fields, curves in spacetime, and so on, which definitely are not matter. Basically the materialist believes in whatever our best physics tells us about. Also, I am going to use the terms “materialism” and “physicalism” interchangeably. In some discussions, “physicalism” is instead used for a particular version of materialism, that we’ll call “identity theory.” We’ll get to that in a few weeks.
Also, for the time being, these are only views about what substances there are. There are further debates about what kinds of properties there are; and these debates also leave open what further ontological commitments one takes, such as whether events or numbers exist.
A third group of philosophers disagrees with all of the views just mentioned. These philosophers are dualists. They think there are two kinds of substances: mental, non-physical substances, on the one hand, and physical substances on the other.
These views come in different versions too. One would be the view that says that God is one substance, and spacetime is another, and that’s it. But a more natural view would say that there are many mental substances, and many physical substances. This is the view we’ll work with.
The debate we’re setting up is between these kinds of dualists, and philosophers who instead have a materialist/physicalist picture of the mind.
On the dualist view, everything that is able to think and feel and be conscious has a non-physical, “immaterial”, purely mental substance associated with it. Philosophers call these souls. They are something like mental or spiritual engines, that are essential to and fundamentally do the thinking and feeling. Souls are separate from the physical world and aren’t made up of any physical parts. (On some views, they’re not made up of mental papers, either; but this is more controversial.)
Perhaps one of the souls is God. What’s we’re going to focus on is that, on the views we’re considering, every human mind also involves a soul. While the body is alive and still functionining properly, the soul is connected to it somehow. It feels things that touch the body, and is usually able to control some aspects of the body’s movement. But it’s possible for the soul to go on existing even after the body is destroyed. In principle, souls can exist independently of bodies or other physical things. (They aren’t like waves or smiles.)
Are you identical to your soul? Different dualists will give different answers here. Some would say yes. Others would say you are some kind of combination of your soul and your body. These views agree though that in order to think and feel, you need to have a soul.
On the materialist view, on the other hand, the only substances there are are physical ones: things like brains and bodies. When these are arranged in the right ways, and have the right kinds of properties, then thinking and feeling and self-consciousness happens. There aren’t any such non-physical substances as what the dualists call “souls.” (Of course, in everyday talk, we’ll often use the word “soul” in a more innocent way, that’s broader than the way the dualist is using it. Materialists can do that too. But in this class, let’s stick to the dualist’s usage.)
We took up this question near the end of class. Some natural ideas are that the materialist will say that since minds aren’t souls, they must be physical substances instead. Perhaps they’ll say that minds are brains; or they might say instead that minds are whole bodies.
But there’s a more subtle possibility, too. Materialists don’t have to say that minds are any substances. Not a mental substance nor a physical one.
Consider the notion of a hike. We’ve got some hikers, their clothes, the dirt path they’re walking on, the oxygen they’re breathing, the sweat on their skin. All of those are plausibly substances. But now what substance is the hike? Is it one of them? Is it some combination of them? Is it a further substance, that I neglected to list?
One option is to say is that the hike isn’t any kind of substance at all. The word “hike” is a noun, but hikes aren’t things in the same robust, full-blooded, sense that hikers and sweat are. Hikes can’t exist independently. They’re more like waves or processes. So “taking a hike” is fundamentally very different from taking an object, like a ticket. When other things, that are substances, are arranged in certain ways, and have certain properties, then a hike takes place.
So one way to be a materialist is to argue that the mind is a physical thing or substance, like the brain. But another way to be a materialist is to say that talk of minds is like talk of hikes, or smiles, and so on. The mind isn’t any kind of substance. When a person has a mind, there isn’t some specific kind of object we’re saying the person has, neither a physical object nor an immaterial one. Rather, to say 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 other things, we say that you’re “taking a hike.”
This view of the mind still counts as a materialist view, because they say that the only substances there are are material or physical substances. Thinking and feeling doesn’t involve any extra, immaterial substances in addition to bodies, brains, and whatnot.
A dualist can agree that minds aren’t special kinds of substances; what’s crucial to their view is that there are such substances, souls, and that to think and feel and have other mental properties, you need to have a soul. Whether we should say minds are identical to souls, or whether mind-talk is instead like talk of hikes, is something they could have different views about.
Dualists and materialists both get to use words like “minds” and “mental”. They agree that we have mental states and processes — we think, feel, have experiences, are self-conscious, and so on. They have different pictures about what’s needed to explain this. The dualist thinks that mental lives only happen when some immaterial substance, a soul, is involved; it’s what fundamentally has the mental properties and it has only a loose conncection to physical brains and bodies. A soul doesn’t have physical parts, and in principle, it could still exist even if the physical world went away. The materialist on the other hand denies that there are any substances beyond the physical ones. They’ll have to explain what’s involved in having a mental life in other ways. As you’ll see as we proceed in the class, different materialists go different ways about how to explain this.