Natural Sciences and Human Sciences (The problem of consciousness, Part 4)
Click on this movie to see the first episode of Dr. Susan Greenfield's BBC 1 documentary Brain Story - 'All in the mind'.
At this point in our discussion, we enter into an enquiry that philosophers label the 'mind-body problem' which is linked to the problem of identity. It's worthwhile investigating into the various theories, if only to yield some insights into the mystery of consciousness.
The materialist theory of consciousness
Greenfield argues that 'you are your brain'. Your inner world of consciousness is a matter of electrical activity inside your brain. So for example, when you saw that red apple you had for lunch, certain physical causes and effects created the experience of redness in your consciousness: first, light was reflected off the apple into your eye. Here the light was focused onto your retina to create an image. Next, the photo-sensitive cells on your retina triggered electrical pulses which moved down the nerve pathways that connect your eye to your brain. Then the electrical pulses caused something to happen in your brain to give you the visual experience of seeing a red apple. Your mind, or mental perception of the world, is just what goes on physically in your brain. In short, you are the sum of the different parts of your brain: the cells that cause different electrical impulses depending on ther function; the nerves that transport those impulses from your sense receptors to your brain; the neurons that fire when you those electrical impulses reach the brain and so on.
The dualist theories of consciousness
There are two versions of this theory:
Rene Descartes (1596- 1650) argued that 'you are your mind'. He devised the theory that the mind and body are separate entities and capable of existing independently of eachother. In short, Descartes believed that when something happens in the brain, something else had to happen - your brain caused something to happen in your mind. The brain and mind may interact, but they aren't identical. How does Descartes argue his case? He gives us the classic sceptical method of doubt:
P1: My body (or anything made of physical matter) is something the existence of which can be doubted.
P2: I am not something the existing of which I can doubt (since some doubting is actually going on...)
Conclusion: Therefore, I am not my body.
I am, Descartes concludes further, a thinking substance made entirely of mind.
Property dualists differentiate between physical and mental properties, rather than substances. Yes, human behaviour can be explained by certain brain states, but there is something else, over and above the physical, that characteries our conscious, mental experience of the world: these are explained in terms of mental states or properties. Unlike materialists, property dualists would argue that our minds are not reducible to the sum of the parts of the brain; we are somehow more than the some of our parts. We'll have a look at the arguments that represent this view later.
But for now, now, we are left with three alternative views of consciousness:
1. The hard scientific view that consciousness is reducible to the individual workings of the brain.
2. Descartes’s view, which very few people would be willing to defend these days, that consciousness is an immaterial substance that interacts with our physical body.
3. The very unscientific view that there exist these non-physical, so-called ‘mental properties’ which make up what we call 'consciousness'.