Scientific American has an interesting article called Brain Scans Help Scientist's "Read" Minds. Notice the quote marks around the word read. They are there for a good reason. Neuro scientists are not reading minds.
They are correlating brain states and mental states. This far different than knowing the actual content of a mental state.
In this particular study, researchers studied stimulus-response patterns using magnetic resonance imaging (MRI) scans of people's brains. In one experiment, they asked the patient to look at one and only one image (out of two possible choices). Then, by looking at the brain scan, they were able to predict which image the subject looked at. It is not clear how they verified which image the subject looked at (perhaps they asked). In a second experiment, an image was flashed quickly to a subject -- so quickly, in fact, that the subject could not tell exactly what they looked it. Brain scans, however, confirmed which image had been shown.
Why is this significant?
According to the article, if scientists could gain a true understanding of the neural basis of subjective experience, it might one day "allow for reliable prediction of a person's mental state based solely on measurements of his or her brain state."
Predicting mental states is all well and good. However, this is still a far cry from actually knowing the contents of a person's thoughts. Why will scientist's never be able to read a person's thoughts? Because brains don't have thoughts. Minds do. And minds are not material.
You see, to a strict materialist, the mind = the brain and vice versa. Immaterial things like minds and souls do not exist. This view of reality holds to the presupposition that the laws of chemistry and physics can ultimately explain everything.
This view of the mind, also called physicalism, is self-refuting. For if it were true, then our thoughts are ultimately not true -- they are simply the result of neural firings. Our thoughts would be determined by fixed laws -- and fixed laws lack contingency. If fixed laws determine our thoughts, which include our thoughts about truth, then the beliefs which we hold to be true are merely neural firings in our brain. We believe them to be true because the laws of chemistry and physics cause them to be true -- rather than our thoughts actually corresponding to reality. Therefore, the argument for the truth of physicalism commits suicide.
So what are thoughts? Thoughts are things which minds ponder. You might say they are properties of the mind. What are minds? A mind is a capacity of the soul. What are brains? They are physical things. They are properties of the body. They happen to correlate with minds -- but they are not minds. It is a critical distinction.
Why do you say our thoughts are determined by fixed laws? The brain is governed by physical processes at a sub-atomic level, and at that level we see indeterminism everywhere. Such indeterminism might aggregate up to consistency (which is why all the vibrating electrons in your arm still form a solid with predictable movement), but it is at least possible that the brain doesn't aggregate things up to that level.
Furthermore, the network effects we have in effect in the brain are so huge that we don't know if they're deterministic or not. There are so many permutations that everything could be fixed, yet still be indeterminate in practice; it would be impossible to gain sufficient knowledge of the state of the system to determine a future state of the system, even if we were able to control all inputs to that syste, (a big if on a global scale).
Finally, to be logically consistent you can't state that the idea is self-refuting; if 'all' thoughts are is a collection of neural firing, then I could argue that they are an ultimate reflection of truth. No perception or worldview or distortion is applicable; they merely respond to the truth, i.e. that which is.
Posted by: Paul | May 10, 2005 at 19:19
Paul,
I am not following your argument. If everything reduces to physical laws (chemistry, electricity, physics), then our minds reduce to it as well (if you are a physicalist). Sure, it may be complicated. But, complexity <> indeterminancy.
If you are a physicalist, you have no where else to go to explain how the mind works but to matter itself, and the physical laws which govern matter.
Now, it may be that you are arguing for something other than matter -- vitalism, life-force, soul or whatever. But based on your prior comments, I don't think you want to go there.
Therefore, my argument stands. If you are a physicalist, the reason you believe physicalism is because of the physical laws governing the matter in your brain -- not because physicalism is true.
Posted by: Jeff | May 13, 2005 at 11:02
Complexity doesn't equal indeterminacy, although it can be sufficiently complex that we couldn't tell the difference. But assuming for a moment we need something more than that, we're talking about operations that potentially occur at a sub-atomic level, where things appear to be indeterminate. So purely relying on a physical mechanism we can get to a level of indeterminate behavior that could generate what we recognize as the human mind (I think this is the argument that Roger Penrose makes, and has been criticized for; I'm looking forward to doing some reading on that subject).
So it might be so complex that it would give the appearance of indeterminacy, or it might actually be indeterminate. Either way there's an argument to be made that it's rooted in the physical, and therefore is the only thing that *does* reflect the truth. I'm not so sure about that - more thinking required.
Posted by: Paul | May 13, 2005 at 15:54