china brain

Functionalism holds that anything that can perform the same functions as a brain is able to have mental states as humans do. There is one common objection to this theory that makes this statement seem almost ridiculous.

There are about 10 billion neurons (brain cells) in the adult human brain. There are over a billion people in China, but lets just suppose that there are 10 billion people there (The original thought experiment uses China, so I'll stick with it). Imagine that each person is given a set of strings connecting them to a number of other people, who each have their own set of strings connecting them to others. Each person is then given the same duty as a respective neuron in the human brain. The whole nation, the "china brain", is now able to carry out every function a brain could potentially carry out. Would this china brain achieve mental states, and thus consciousness?

According to a functionalist, the answer should be yes. But how can that be? A functionalist could very well argue that the china brain would think no differently than a human, but it seems to go against all common sense that this be the case. It seems, looking at this example, that an actual human brain is necessary to achieve mental states. This is a belief of the type identity theory of the mind, discussed below. So in light of this objection, type identity theory actually seems more plausible.

more stuff on the mind. i know its getting old, but i need something to write about.

Now I'll illustrate the benefits of functionalism.

There are some different forms of functionalism, but in this post I will be referring to machine functionalism. This form of functionalism is a substrate neutral theory of mental states. Its believers hold that the type of substance performing the function has no bearing on whether or not there exists within that thing mental states. To make this more clear, a machine functionalist believes that the brain is not the only thing capable of having mental states. A computer able to perform the same functions that a human brain can, would indeed have mental states. If a computer were able to replicate the functional role that pain serves in the human body and brain, than a machine functionalist would say that the computer actually is in pain.

Functionalism effectively solves the problem of multiple realizability and the plasticity of the human brain. Just because the brain damaged patient mentioned below is in two different brain states, it does not mean to a functionalist that he is in two different mental states. A functionalist holds that because in both cases the patient is truly recognizing his mother, he is indeed in the same mental state.

This theory also allows for artificial intelligence. If a machine can replicate the functional roles that brain states have, then it has mental states. This is because functionalism interprets mental states not by what the brain is doing at that time, but by what function the mental state is serving. The physical substance doing the thinking does not matter.

So functionalism solves the problem of multiple realizability that still seems a problem for the type identity theory of the mind. But it's still not a perfect theory. I'll illustrate the disadvantages in my next post.

mind continued

The type identity theory of mind seems fairly straightforward, but is not without its flaws. One objection to this theory involves the concept of the plasticity of the human brain. Plasticity is a word used to describe the brain's ability to adapt to new conditions. People who suffer brain damage may lose the ability to be in certain mental states (they may be unable to recognize their mother, as an example). Because of this unique feature of the brain however, some patients may regain the ability to recognize their mother over a period of time. This is because when one area of the brain is damaged, another can take its role. This argument, called the argument of multiple realizability, shows that although the subject is in the same mental state (recognizing his mother), he is not in the same brain state. Thus it follows that brain states are not identical to mental states, which is the central claim of the type identity theory.

Although this argument seems to disprove the main point of the identity theory, some of the details can be modified to make the issue not so clear. A type identity theorist may in turn reply that the brain damaged patient actually is in a different, albeit subtly different mental state than previously, even though in both instances he is recognizing his mother. They may argue that the patient isn't recognizing his mother in the same exact way that he used to. This is however somewhat difficult to prove (does the patient feel different in some unexplainable way every time he looks at his mother?)

It seems that this still may be a problem for the type identity theorist.

mind

I have to write a paper refuting or agreeing with some frequent objections to the type identity theory of mind, functionalism, and physicalism in general. I figured I'd jot down some ideas even though the paper isn't due for a while.

The three arguments I have to discuss are the zombie argument, the inverted spectrum argument, and the mary's room thought experiment which I describe in a previous post. But before I go into detail over these objections I should first define the two most popular theories of mind: type identity theory and functionalism.

The type identity theory of the mind states that mental states exist and literally are brain states. Pain is pain only because my brain goes into the "pain" state. Every time I am burned, my brain acts up in a predictable manner. This means that I can be in pain without even touching a sharp needle or hot stove; as long as my brain is for some reason in the pain state. Pain, and any other mental state, is defined not by its function, but by what is going on physically in my brain and nothing else.

Functionalism on the other hand says that mental states exist and are defined only by their functional roles. So for example, the mental state of pain is defined by what causes it, and what it causes; not by what is going on in the brain at that time. Pain is only pain because it is caused by harmful external stimuli, and because it's function is to get us away from the harmful thing as soon as possible.

Both of these theories of mind have their benefits and downfalls. I will illustrate there shortcomings in my next post.

on identity

Let's say my friend makes a decision that I think is really stupid. Maybe he stole a car, or forgot to do his homework. I hear that he did this and I am really mad at him for doing so. The next time I see him, I say "if I were you, I wouldn't have done that. That was the stupidest thing you could've done." But does it make any sense to say this? If I was my friend, I would have made the same decision because, well, that's the decision my friend would make. I am my friend and so therefore I must make every decision the same way he would. I think that how you make your decisions is a fairly important part of what makes you who you are.

Sometimes I wish I could be another person for a while, and not because I'm dissatisfied with who I am. It's hard to explain, but every night I go to sleep and I always think there might be a chance that I'll wake up a different person the next day. But I never do; and it seems almost possible that I should, because when I'm asleep and I'm not dreaming, I have no sense of self, so how do I become me every morning instead of someone else?

I wonder if it will ever be possible for us to be able to think like another person. Philosophically, it seems impossible, because in order for me to think like another person, I myself have to observe how that person is thinking while simultaneously thinking freely exactly as that person would think. But it is impossible for that person to think freely while being effected by my own thoughts of introspection. Please leave comments. ;(

on qualia

Imagine a very young scientist, named Mary, who has lived her whole life in a black and white room. Mary is brought up by extremely smart experimenters who teach her almost everything there is to know about things, especially color. Whatever the experimenters haven't taught Mary about color, she learns herself through scientific observation. When I say Mary knows everything there is to know about color, I mean exactly that. She knows all the wavelengths, she knows exactly what goes on in the human eyes and brain when one experiences color, etc. One day, as an experiment, one of the observers throws a red tomato into the room. Does Mary learn something new? The answer is obviously yes. But what are the implications of this?

If we suppose that Mary knows all the physical facts about color, and yet she learns something new, by simply experiencing color, that must mean there are more than just physical facts to learn. It also means that there are some things we simply can never learn. For example, we can never know what it is like to be able to find our way through the house when the power goes out by using echo location. More specifically, we can never know what it is like to experience this in the same way that say, a bat would. We can learn all we need to know about echo location and sonar, and we can build machines, but we can never experience it as a bat would without being the bat. And its impossible for you or for me to be a bat. Because once I'm a bat, then I'm not me. So I'm not a bat.