sam brown, explodingdog
Monists are philosophers who think there is only one kind of substance. This is the main way the term “monist” is used in philosophy. Sometimes it’s used instead for the more radical views mentioned in the next two paragraphs.
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 tend to use the terms “materialism” and “physicalism” interchangeably. In some discussions, “physicalism” is instead used for a particular version of materialism.
Also, 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.
Of course these philosophical uses of terms like “material” differ from popular uses…
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. There just are those two substances, and they’re each of their own kind. But a more natural view would say that there are many mental substances, and many physical substances. This is the view we’ll be thinking about.
The debate we’re setting up for our next classes 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 parts, either; but this is more controversial.)
Perhaps one of the souls is God. What’s we’re going to focus on instead is that, on the views we’re considering, every human mind also involves a soul. While the body is alive and still functioning 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 may be possible for the soul to go on existing even after the body is destroyed. Souls are at least logically independently of bodies or other physical things. (They aren’t like wrinkles or smiles.)
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 course, let’s stick to the dualist’s usage.)
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’s logically independent of and merely in some way connected 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. Different materialists try to do that differently.
Which mental states or properties require souls? Some dualists think a soul is required to have any mental properties at all. Other dualists think that some properties (like sensations and emotions) could be available without souls, but that souls are required for other mental properties, like thinking and reasoning and self-awareness. Other dualists think the reverse: that thinking and reasoning could happen just in physical brains, but that feelings aren’t possible without souls. What these dualists agree about is that for at least some mental properties, you can’t have it without having a soul.
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. (The influential philosopher Descartes, who wrote in the 1600s, called these “unions.” We’ll be reading some passages from the contemporary philosopher Peter van Inwagen, who calls them “amalgams.”) What these different dualists agree about is that in order to think and feel, you need to have a soul. The materialist thinks you don’t.
We will discuss complexities about the relation between you and your soul (if you have a soul) more in later classes.
What substance will a materialist say the mind is?
It’s natural to think that the materialist will say: 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 wrinkles or echos or smiles. Or maybe they are events. Either way, “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.
One way to be a materialist is to argue that the mind is a physical Thing or substance, such as perhaps the brain. But another way to be a materialist is to say that talk of minds is like talk of hikes. 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.
In fact, 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 different dualists could have different views about.