More on Materialism and "Aboutness"

Commenter BeingItself asks: "If I was to draw a picture of my girlfriend, would that drawing be about my girlfriend? Surely a drawing is material. What is it about brains such that their patterns cannot be about anything?"

Good question! I've examined the James Ross article on this blog a few times, but it's always good to revisit this basic idea from different angles. This problem is an interesting one that materialists ought to grapple with, but too often they misunderstand it or just wave it aside.

Think of the Big Dipper. In the West, it looks like, or represents, a soup ladle.



But does the Big Dipper itself, apart from our interpretations, have anything whatsoever to do with soup ladles? Is it really about soup ladles, outside of our interpretations that we apply to it? Of course not. Soup is a salty liquid food, and a ladle is a metal spoon for scooping it up. The stars that make up the Big Dipper are enormous balls of hydrogen gas. Nothing relating to soup or ladles at all. Hell, in other cultures the Big Dipper is supposed to look like a big bear, hence it's official name: Ursa Major.

But what if we had the technology to create and move stars around? And what if we filled in the details of the Big Dipper, complete with pouring soup, so that it looks even MORE like a soup ladle than it does now?



Is it really about soup now? No, still not. It's still just a bunch of balls of hydrogen gas arranged into a patter that we interpret as a soup ladle, but apart from us is not about soup ladles.

Now let's say that the technology is not there yet to move stars around, so instead we use some small clumps of glowing electrons on a glass screen. We arrange the glowing electrons the same as before, first like the Big Dipper, then fill in more details. Again, are the glowing electrons about a soup ladle? Again, apart from our ability to apply a pattern onto something, the electrons are not about soup ladles. They are just electrons that are glowing, that have certain charges, and that's it. We've just arranged them into a patter that we call "soup ladle."

Of course, what I'm talking about here is a computer screen. Materialists often think that an easy counter to dualist claims is to point to the existence of computers, saying that computers are about things and there's no problem there, so why should there be a problem with explaining the aboutness of our thoughts? But computer output is no different from the Big Dipper above: just arrangements of glowing electrons that we apply meaning to. Without us around to give meaning to the symbols, the output on a computer screen has no more aboutness than the Big Dipper does.

And the same goes for graphite marks on a piece of paper, as BeingItself's original question pertained to. The objective physical situation involves some carbon molecules sticking to wood molecules (which are also carbon), and that's it. The physical situation, apart from BeingItself's interpretation, has nothing whatsoever to do with "girlfriends", anymore than the Big Dipper has to do with soup ladles.

The problem could be phrased like this: for a symbol to have meaning, there must be two ingredients: the physical shape/structure of the symbol + something else.

In the case of BeingItself's drawing, the "something else" is his intentions applied to the otherwise meaningless bits of carbon. In the case of the Big Dipper, the "something else" is our interpretations of an otherwise meaningless grouping of stars.

But in the case of our thoughts, what is the "something else?"

Arguments Against Dualism: The Real Ones

In my previous post, I showed how the popular argument for dualism, that the mind is affected by drugs and brain damage, is no good. So what arguments do materialist philosophers use, then, in arguing for materialism against dualism? William Lycan, a materialist philosopher, offers a handy list:

• Parsimony. It is simply more parsimonious to conclude that everything is matter, in line with what science has discovered so far. And a non-physical "soul" is not parsimonious.

• Transitive arguments. Pain is the behavior of screaming, running away, etc. And that behavior consists of C-fibers firing (or whatever). Therefore, pain is the firing of C-fibers. In other words: Pain = behavior = C fibers, therefore pain = C fibers.

• We ought to believe something exists only based on its causal powers. If it can't cause anything, then there is no reason to believe it exists. Because of the causal closure thesis of physics, that all physical effects have physical causes, this leads directly to materialism.

• Conscious causes have physical effects. From physics, we know that all physical effects have physical causes. Therefore, consciousness is physical.

And as Lycan says, "I know of no other arguments for materialism." Of course, he also shows why the above arguments don't work.

Non-Reductive Physicalism: Functionalism

I. What is Non-Reduction?

Non-reductive physicalism says that everything is exhaustively describable by physics, and the human mind is entirely explainable by physics, but that we humans have special explanatory interests that cannot be neatly explained in physical terms. To take an abstract example, something might be entirely describable in terms of physics, and the physical properties can be stated: P1, P2, P3, P4, P5, P6, etc. But because of our human interests, we might be interested in grouping and describing physical properties less than 5, and so WE create a logical grouping and subsume P1 thru P4 under the property Q1. So Q1 just means: has physical properties P1, P2, P3, P4, and "not Q1" means that it has physical properties P5, P6, etc. The physical properties are called "first order properties", and our logical groupings, created entirely by us, are called "second order properties."

Another analogy is to consider juniors and seniors in college. We refer to this group as "upper classmen." So "junior" and "senior" are first order properties, and "upper classmen" is a second order property, which is really just a logical grouping of the two first order properties.

So non-reductive physicalism states that our normal talk of mental descriptions ("X believes that P", "Y desires that Q") are just logical groupings of physical properties that cannot be neatly swapped out with physical language, even though everything is ultimately physical. While sometimes colloquially referred to as "property dualism", non-reductive physicalism is better termed as a type of "predicate dualism", meaning that the only dualism happening is in our language, not in reality.

II. The Multiple Realizability objection to identity theory

The main version of reductionism, called "identity theory", states that mental states are brain states. So as an example "pain" is the firing of C-fibers, and the firing of C-fibers is "pain." They are two different names for the same one thing, in the same way that Mark Twain and Samuel Clemens are two different names for the same one person. This means that you cannot logically have pain without the firing of C-fibers and vice versa, in the same way you cannot logically have Mark Twain without Samuel Clemens.

Concievability Arguments

But, according to the multiple realizability argument, you can logically have pain without the firing of C-fibers. Just imagine an alien telling you that he is experiencing pain. But the alien, having a completely different evolutionary history than us, would not have C-fibers. Or think of a future artificial intelligence. Do we want to say that such a being, having circuitry and thus no C-fibers, will never be able to experience pain or any other mental state? The fact that it is even logically possible for such beings to experience mental states is enough for the argument to succeed. It is not logically possible to have Mark Twain without also having Samuel Clemens, for as soon as you are picturing Mark Twain, you are also picturing Samuel Clemens. They are just two names for the same one person.

Likewise, if mental states are just another name for brain states, then it should not be logically possible to picture the one without the other. If the belief that there are 8 planets in our solar system is just another name for the firing of XYZ neurons, then we would have to say that aliens who visit our solar system can never have that belief, since they lack XYZ neurons.

The obvious answer is that mental states can be realized by many different types of physical systems: human brains, alien brains, computers, etc. But if so, then this is non-reductive physicalism: the mind will never be reduced to just physics, since mental states are now abstract concept.

However, since it is controversial whether conceivability is a reliable guide to possibility,  defenders of multiple realizability have sought empirical support for their thesis as well.

Empirical Support for Multiple Realizability

Defenders can appeal to biology and evolution. Since mental states like pain and the like can cause animals to adapt to their environment, then there is good reason to think that if aliens have evolved on other planets they too will experience mental states to help them survive. However, since their evolutionary history is different from ours, they would lack the exact same neurons and brains that we have.

Another appeal to empirical support is via neuroscience. Neuroscience has shown how the brain can pick up the slack and take over functions if certain areas get damaged.

III. Reductivist Answers to Multiple Realizability

While the multiple realizability argument has caused a general abandonment of identity theory, there have been responses to it.

One way of responding is to say that "pain" is not some general mental category, but rather there are specific pains and each one is its own separate mental event. For example, pain-in-humans, pain-in-martians, etc. So pain-in-humans would then be identical to a certain brain state, and pain-in-martians would be identical to a specific (martian) brain state.

Another way of responding is to argue that mental events are identical to physical events, and each separate brain (like humans and aliens) have some basic physical commonality. Similar to how we once thought magnetism and electricity were two separate physical domains, but now realize they are just one (electromagnetism).

Despite these answers, the multiple realizability argument has been very influential and the majority of philosophers of mind have shifted over to non-reductive physicalism as a result.

IV. Functionalism

The idea that mind can be realized by many different systems is called "functionalism." Mental properties are defined, not by the firing of specific brain processes like identity theory, but rather by their functions. And a function is an abstract concept. The mental even "pain" for example would be a functional abstract concept like "tissue damage warns organism, and causes retreat" or whatever. This idea of pain is abstract, like a computer algorithm. It can then be realized by many different systems, like human brains, squirrel brains, alien brains, and possibly future AI systems.

Think of functionalism as defining mental states in the same way we might define a "knife." A knife does not have to be made out of anything in particular, as long as it fulfills it's function of being able to cut things. So the abstract concept of a knife (a tool that can cut things) can be realized by many different materials and structures.

So a mental state, like pain, is defined as an abstract concept (tissue damage causing wincing, screaming, etc) that can be realized by many different systems.

V. Objections to Functionalism

The problem with functionalism is the opposite of the problem with identity theory. While identity theory fails to attribute mental states to those that (probably) have them (like aliens, AI, etc), functionalism attributes mental states too freely. This is called the "liberalism" objection, as functionalism is too liberal.

Since functionalism says that a mental state is defined by it's function, then all that is required is for a system to be mental. A mental state is defined as an algorithm (tissue damage input causes screaming output) that can be realized by a physical system. However, imagine that the water molecules in a pond temporarily match that algorithm, due to pure coincidence. Functionalism would say that the pond molecules would be feeling pain. Or think of a robot, who is programmed with these mental algorithms but is empty inside, with no conscious mental state at all. It just goes through the motions. Again, functionalism says that this robot MUST have mental states, because mental states just are the physical realization of algorithms. But if it's even possible to have those functions, but not be mental, then functionalism is false.

Reductive Physicalism

I. What is Reductive Physicalism?

The view that our descriptive language of mental events ("x is in pain", "y believes that z", etc) refers to real events and is correct, but will correspond neatly to physical concepts and descriptions. In other words, the mind is "nothing but" physics, and will be completely describable in physical terms when neuroscience is finished. For example, to say that "x is in pain" will end up being describable by physics: "x's neurons 1234 to 5678 are firing".

II. What is "Reduction?"

When us humans learn about entities of type A, and also about entities of type B, because of the language and concepts we use might differ for each one, we may not realize at first that A entities are really a subtype of B entities. When we learn this, we then can go about replacing our original language and concepts for describing A entities with the language and concepts we use for describing B entities, as A entities are "nothing but" B entities. For example, we might use language and concepts referring to light, colors, etc, and then later learn that light is really nothing but a spectrum of the electromagnetic spectrum. So we then "reduce" the original language of color and light ("red", "bright", etc) to physics ("wavelength between 640nm", etc).

 

III. Two Types of Reduction

There are two main forms of physical reduction of the mind: behaviorism, and identity theory.

Behaviorism reduces talk of the mental to talk of behavior. The belief that it will rain is really just the behavior of grabbing an umbrella before going outside, etc.

Identity theory reduces talk of the mental to talk of the physical by saying that mental events are just another name for physical events. They are two names for one thing, like "Superman" and "Clark Kent" are two names for one person. For example, the mental state "the belief P is true" is just another name for the firing of a specific pattern of neurons. There is only one event, not two.

IV. Behaviorism

Mental descriptions are shorthand for types of behavior. To say "X is in pain" is just to say "X is wincing, screaming out, etc.", and that is all there is to a mental event. Since we can't know the contents of anyone else's mind, such as whether they are experiencing the actual feeling of pain or not, we should instead focus on what can be empirically verified.

Problems with Behaviorism: 

1. Collapse of Logical Positivism - Behaviorism was part of the larger project of logical positivism, the view that all knowledge should be either tautological or empirically verifiable. But since the verifiability theory of the logical positivists is itself neither tautological nor empirically verifiable, it refutes itself. Logical positivism died out in the 1950s.
2. Holism of Psychology - Each form of behavior involves a network of other beliefs, all of which are necessary to explain the behavior. If Bob grabs an umbrella before he leaves the house, then this involves a huge network of other beliefs: the belief that it will rain, that an umbrella will repel water, that water falls down, etc. This huge network of beliefs cannot be reduced to just behavior, and will always involve some elements of the mental.
3. Awareness of Your Own Mind - To know you're in pain, you don't need to observe your own behavior in the mirror. You just feel pain, directly. The old joke about behaviorism: What does one behaviorist say to the other after sex? "That was good for you, how was it for me?"
4. Super Actors and Super Spartans - Imagine someone not in any pain at all but is a very good actor, who can convince you that he is in pain. Or imagine someone that is in extreme pain but does a very good job of not showing any sign of it. Behaviorism would have to say that the first person is in pain and the second one is not, when in fact the opposite is true.

Because of this, behaviorism has largely, though not completely, died out. Most reductive physicalists have moved over to identity theory.

V. Mental Descriptions as "Theory"

When we speak of mental states, such as "John believes that X", this is often thought of as an explanatory theory. For example, if John grabs the keys before he leaves, we would explain this behavior by saying "John believes that the car is in the garage" and "John desires to take the car." So mental descriptions postulate unobservable hypothetical entities to explain human behavior, which is exactly what a "theory" is. So when we speak of mental entities like beliefs, desires, and so forth, we are engaging in a theory. Most physicalist philosophies of mind accept this, and take different approaches to it. Behaviorism is the only theory that does not take mental language to be a type of theory, because behaviorism takes mental descriptions to be PRE-theoretic observations. Identity theory, on the other hand, accepts that mental descriptions are a type of theory and that the entities that are theorized to exist (beliefs, desires, etc) are identifiable with specific brain states.

VI. Identity Theory

The identity theory of mind states that the mind is the brain. They are just two different names for the same (one) thing, in the same way that "water" and "H20" are two different names for the same thing. So for example "the belief that P" is just another name for "firing of ABC neurons". They are just two different ways of describing the same one thing. There are two main versions of identity theory:

1. Occam's Razor: Defended by JJC Smart, who said that if there is no reason to postulate extra entities, such as mental entities, then we should favor the theory that postulates less extra entities, per Occam's Razor. So Smart arrives at identity theory via shaving off any extraneous entities.
2. Lewis/Armstrong: defended by David Lewis and David Armstrong, this version arrives at identity theory instead by describing a mental state as a particular kind of state, and then letting science discover what that particular state consists in. For example, "pain" is what, exactly? It is the mental state that causes wincing, screaming, and is caused by tissue damage, etc. Now, let's say that science discovers that "wincing, screaming, etc caused by tissue damage" is caused by brain state X. So, since pain = "wincing, etc", and "wincing, etc" = "brain state X", then by transitivity "pain" = "brain state X."

Problems for Identity Theory:

1. Multiple Realizability: If we accept identity theory, then we have to accept that aliens could never have the mental state "belief that P" since they have a different evolutionary history and don't have the "ABC" neurons that we have. And since "belief that P" is just another name for "firing of ABC neurons", then if you don't have ABC neurons, you can't possibly have "the belief that P."

Or imagine future artificial intelligences. We would have to say that they can never believe that P either, because they possess circuitry and not the "ABC" neurons that "belief that P" is just another name for.

The obvious solution presents itself: mental states can be realized by many different systems, and not just the specific neurons we possess. So a mental description is a description of an abstract concept ("X believes that P if 123"), rather than something concrete (firing of ABC neurons).This is, however, non-reductive physicalism.