Letís move onto the next issue, the problem of substance. Now we face another, perhaps more fundamental problem: What are objects anyway? Is it possible to say anything enlightening about the meaning of talk of objects, of things, of bodies, of substances (Iím going to use these terms interchangeably)? You might not think anything interesting could be said about this question, but we did manage to say something enlightening about the meaning of existence. So letís give it a try.
Letís go back to our example of the apple. I propose to ask: What is the apple itself? First of all, you might wonder now what it is that weíre supposed to be confused about. You know what apples and tables and trees, and other bodies, are; you eat and bump into them all the time. So maybe the notion of an object is primitive: it canít be explained any further. Primitive, thatís a term that is useful to introduce when weíre doing metaphysics. A word is primitive if it is meaningful but not capable of being defined. But at least we should try to see if the notion of a body can be explained in terms of something else.
So you might say: what about fundamental particles, maybe quarks? Donít they explain the notion of a body, since fundamental particles make up bodies? Well, thatís not what I mean. Fundamental particles are, after all, other bodies. So the question is, is there any other category of being that can be used to explain what physical objects are?
And so here you might say: I have no idea what other category of being could be used to explain the notion of a body. But sure you do. What about properties and relations? Bodies have properties and relations, and it seems that we can describe bodies only by mentioning their properties and relations. The only way we can talk about the apple, it seems, is by describing its properties, or how it is related to other things. For example, we can say the fact that it is an apple is a property of the object on the table; its redness is a property; its size and composition are properties; its being on the table is a relation; its being in the room, and being bigger than other apples, are also relations. So it appears that the only way we have of talking about the apple is to mention its properties and relations. And similarly with all other bodies.
So letís go back to the question: "What are objects anyway?" Now we can say what general sort of answer weíre looking for: we want to know how objects, or bodies, or whatever you want to call them, are related to their properties and relations. Letís leave aside relations now for simplicity. So Iím just going to ask this: What is the relationship between objects and their properties? This is supposed to tell us better exactly what objects are.
And this question, "What is the relationship between objects and their properties?" can be explained further. As follows: "Are objects just the same as a collection of properties, or are objects not the same as, but different from their properties?" This appears to be a fairly strict dichotomy: either objects are the same as collections of properties, or they are not the same. And so there are two theories of the nature of objects. The bundle theory, on the one hand, holds that objects are nothing more than collections of properties. The substance theory, on the other hand, holds that objects are something over and above their properties, namely substances. So let me explain each of these two theories a little bit better. Then after I explain each one briefly, weíll look at some arguments for and against each theory.
According to the substance theory, a physical object is something over and above the properties that inhere in it. Thatís philosopherís talk -- to speak of properties as "inhering" in a thing. It just means that the thing has those properties. Anyway, according to the substance theory, in at least some sense the substance can exist without its properties. Even if itís physically impossible that a substance would lack any properties at all, we can speak of the substance itself as distinguished from its properties. Now the substance considered all by itself, considered without any reference to its properties, is what has been called a "bare particular." Itís "bare" because it is considered without any properties, and itís "particular" because itís not abstract. More about "bare particulars" in a minute. So there you have a very basic introduction to what the substance theory says. It says thereís a basic difference between substances, or bare particulars, and the properties that inhere in those substances.
Now for an equally basic introduction to the bundle theory. According to the bundle theory a physical object is a bundle, or collection, of properties. Hence, you cannot even conceive of a propertyless object: the object just is its properties, and so if you take away its properties you take away the object itself. Think of the apple: but donít think of its color; donít think of its shape; donít think of the fact that itís a kind of fruit; donít think of the cells that its made of; donít think of its taste; and so on. Think of the apple, but donít think of any of its properties. Is that possible? The bundle theorist says: No! Not possible! So the apple is no more than a collection of properties. There isnít any more to the apple than that. In particular there is no "substance" that these properties "inhere in."
So which theory of objects is correct, the substance theory or the bundle theory? Well, letís look at some arguments on both sides. First, for the substance theory. Letís begin with something we might call the argument from grammar. This has as its conclusion that the substance theory is correct. The argument goes something like this. When we say, for example, "Snow is white," there is a subject, snow, and we are saying of it that it is white. It makes no grammatical sense to speak of "whiteness" disembodied, without snow (or some subject) that is white. The only way to make a meaningful claim about anything is to speak of a subject, and we predicate various properties of this subject. When we talk about physical objects, at least, this subject of predication is called the substance. So in order to make meaningful claims about physical objects, we have to refer to substances; but we make meaningful claims about objects all the time; therefore, substances exist.
Now, I suspect that this argument from grammar is no good. The bundle theorist definitely would reject it. Let me explain why. The argument says: just because there is a grammatical subject in a sentence, we are referring to what might be called a metaphysical subject, a substance. But how does that follow? It doesnít seem to follow. Well, OK, the argument from grammar gets at least the following right: in order to make meaningful statements about bodies, we have to talk about subjects. But why couldnít a subject in a meaningful statement refer to a bundle of properties? For example, consider the statement, "Snow is white." Why couldnít we be saying that a field of snow is just a bundle of properties like being made up of ice crystals, being cold, being a few feet deep, etc. And then we say of something about this bundle of properties, that it includes the property of being white. That seems like a reasonable way of understanding this claim that snow is white. And we donít have to talk about any substances. So thatís a way to show that we can make meaningful statements about bodies without referring to substances.
Hereís a second argument for the substance theory. It would go like this. Whenever we conceive of one of an objectís properties, like the redness of the apple, we have to conceive of the object that has that property. You canít conceive of redness, or any other property, all by itself. The point is that whenever you think of a property, you have to think of it as a property of something. And well, what itís a property of is just a substance. There is no conceivable thing such as redness all by itself, or being four inches wide all by itself -- thatís nonsense. Itís always a substance that is red, or that is four inches wide. Therefore, substances exist.
This might be a slightly better argument, but it also doesnít seem to be valid. The main claim in the argument is that, since -- hereís the big premise -- we canít think of properties all by themselves; therefore -- hereís the conclusion -- they must be properties of substances. But does that conclusion follow from the premise? I donít think so. Why couldnít we say: they just have to be associated with a bundle of other properties, which bundle we call an object, or a body? Do you see the point? An individual property, we might concede, canít exist by itself. But that doesnít mean that substances have to exist: maybe these bodies that exist are just bundles of properties, and an individual property canít exist separately from such a bundle.
Philosophers are pretty sophisticated in their own way and they can think up all sorts of ways to defend their views. So the substance theorist might have some ways of backing up these arguments. But we donít have time to get into it too deeply, so letís move on and consider some arguments against the substance theory.
First, thereís the problem of knowing what the relation is between a substance and its properties. For example, whatís the relation between the apple, considered as a substance, and its redness? The substance theorist may say: well, a property inheres in a substance. Thatís the word he uses: "inheres." A propertyís inherence in a substance is kind of like being part of the substance. But itís definitely different from just being a part. When I say, for example, that the apple is red, Iím saying that redness inheres in the apple. But then what is inherence? How much sense does that make? It seems all I can say is that itís what I mean when I say the apple is red! But thatís not very helpful. So what exactly is the relation between the substance, an apple, and its property, the redness? Thatís the first problem.
Well, here the substance theorist may just say that the name of the relation is "inherence," and that inherence is a primitive concept. It canít be explained any further, but it doesnít need to be explained any further. Itís like this: we know what it means to say that the apple has the property of redness, or the property of being juicy. It doesnít matter that we canít explain what this talk of a substance "having" properties, or a property "inhering in" a substance, amounts to in any other terms. We have to start somewhere -- we canít define everything, or if we try weíll run out of words!
So suppose the substance theorist manages to wriggle out of that problem. But hereís a second problem, which is probably more serious. We might say that the very notion of a thing with no properties, a "bare particular," as I said, is absurd. We just cannot conceive of a thing without any properties. As soon as we get the fuzziest notion of a thing in mind, we are thinking of some property or other! The problem isnít just that itís physically impossible that we might stumble across a bare particular, or a propertyless thing on our way to class. The point is that the very notion of a propertyless thing is impossible: we just have no such notion.
That at least is what the bundle theoryís advocate might say. And we are now getting into arguments for the bundle theory. In fact we can say that the second argument against the substance theory is just our main argument for the bundle theory. Iím just going to make one argument for the bundle theory, and itís at least a lot like this second argument I gave against the substance theory.
So the argument for the bundle theory goes like this. The basic idea is that however we might choose to conceive of, or describe a thing, it will be a conception, or a description, of a property of a thing. In other words, there is nothing that can be described, or even conceived, about a thing, which is not a property of the thing. (Or a relation of the thing, but remember weíre ignoring relations for simplicityís sake.) We cannot have the slightest idea of any aspect of the thing which is not a property of it.
So what does that imply? It implies that we cannot have any conception whatsoever of a "bare particular." As the English philosopher John Locke said, a substance by itself, apart from its properties, is something "I-know-not-what." The only way that we can conceive of an object is by conceiving of its properties.
Therefore to conceive of an object just is to conceive of a bundle of properties. The only conception we can have of an object is as a bundle of properties. The bundle theory wins out, on this view, simply because itís the only game in town: the only way we can conceive of things is as bundles of properties. We couldnít imagine a bare particular, a propertyless substance, even if we tried. So the bundle theory is correct and the substance theory is wrong.
I and I think most philosophers these days think this argument, or one a lot it, is a very powerful argument. How could the substance theorist reply? How could we hold onto the substance theory if we have no conception of substance as distinct from properties and relations?
Well, as far as I can tell, the best that we can do is that we can say we have a very basic sort of idea of substance. Namely, substance is the subject in which properties inhere. Thereís a basic idea we can have. So the substance theorist might say this: all right, fine, we conceive of substances by conceiving of their properties, but I the substance theorist continue to say that the thing we are conceiving of is the thing that has those properties. And that thing is different from the properties. So we can have a notion of a substance as "the subject in which properties inhere." The substance theorist would maintain that we should just content ourselves that we are surrounded by lots of examples of subjects in which properties inhere. All the bodies around us are subjects in which properties inhere. Iím sure the bundle theorist would not at all be satisfied with that, but letís just leave it at that.
Finally, letís consider what arguments might be raised against the bundle theory. There are several, but Iím going to bring up just one. Itís about what it means to talk about a bundle of properties. You have to admit that when you first hear it, it sounds kind of mysterious. The apple is supposed to be a bundle of properties, redness, being four inches wide, juicyness, and so on. But if there isnít a substance that underlies all these properties, then what exactly is the relation supposed to be between the properties of a thing? The apple is both red and juicy, right? According to the bundle theorist, there is no substance that is the apple. Thereís just a "bundle" of properties like being red and being juicy. So how does it happen that all of the properties of the apple on the table happen to be found together? The bundle theorist says they are "bundled" together, that they are a collection. But how are they tied together? What collects them together? Why should it be that redness and juicyness just happen to be found together on top of the table?
The substance theory can explain this but the bundle theory doesnít seem to be able to. The substance theory says: redness and juicyness are two properties that are found together on top of the table, because itís the apple thatís red and juicy. And the apple is a substance in which those two properties inhere. If we like the bundle theory, it seems we have to throw up our hands and say, "I donít know why bunches of properties are found associated together."
Well, to be honest with you Iím sure actual bundle theorists would have something clever to say in reply. But weíll have to cut them off in the interests of time.
If you have found all of this stuff about the problem of substance baffling, let me see if I can make it a little bit clearer by giving a completely different sort of example. A concluding example, Iím not going to spend too much time on this. Have you ever wondered what your mind, or your soul, is? You can identify individual thoughts, individual feelings, in your mind. But do you know what the mind is, that has these thoughts and feelings? You can imagine all sorts of mental goings on, but can you imagine the mind itself? I donít think so. The only way we have of understanding, by introspection, what our minds are is by considering various particular thoughts, feelings, decisions, and so forth in our minds.
So then suppose someone comes up and says: well, you really donít have a mind, or a soul -- at least, you donít have any mind or soul that is distinct from your thoughts. So all there are is a series of thoughts and feelings that are associated with your body. Thereís no mind thatís something over and above your thoughts and feelings. This would be the view of someone who held a bundle theory about the mind. The Scottish philosopher David Hume held a theory of mind like this.
Now I think some of you might want to protest strongly and say, "I most certainly do have a mind, or soul, which is distinct from my thoughts and feelings -- why, that mind is just exactly what I call my self. Hume seems to want to deny that I have a self! Thatís absurd, and even a little offensive!" Now if you have this reaction, then you have a substance theory of mind. You think that there is something -- you may not know what but something -- which has the thoughts and feelings, and the thoughts and feelings are in your mind, in about the same way that properties inhere in a substance.
Philosophers have talked, as you might have guessed, about both physical substances, or bodies, and mental substance, or minds. And as I think you can see, the problem of substance arises in both the physical and the mental realms. Iím going to have to leave the discussion there, as difficult as it is.