There are two schools of thought regarding the nature of the mind and Brain – materialism and dualism. Materialism contends that the mind is entirely physical (the result of brain activity) while dualism suggests that the mind and brain are separate entities. Dualism is sort of like the “ghost in the machine” point of view. Now, most contemporary philosophers and psychologists endorse the materialist viewpoint. All the neuroscience evidence points to the fact that you need a functioning brain to experience consciousness. Another way to put it is that the mind depends on the brain.

There is one major problem with materialism that has not been resolved -the problem of qualia. Qualia are attributes related to what it is like to have an experience. We describe things as how they look, smell, feel, etc. The problem of qualia can be illustrated by a thought experiment put forth by the philosopher Frank Jackson about a Color scientist named Mary.

Mary, as I just said, is a color scientist. She has studied everything about seeing color. She knows about the various wavelengths of light, the different hues and saturations of color, etc. The thing is, Mary lives in a black and white world. Everything she sees is either black or white. So, one day she sees the Color Red. Is there something about seeing red that differs from her knowledge about that color? Of course there is. It’s the personal experience of seeing the color. All her knowledge about the color red would not equate to the first hand experience of what the color actually looks like. There’s something extra about the experience that Mary did not know.

So, why is this a problem for the materialists? If the mind is a purely physical thing then we should be able to describe it in purely physical terms. Yet, there is no way to quantify the experience that someone has when, say, they are seeing the color red. We can identify specific neurons that are activated when we see red but we still do not know how they produce the experience of red. A totally physical explanation of mind should be able to explain this experience.

Still, the problem of qualia is no reason to discard materialism. Science provides us with an objective third-person (observer) description of the world. It cannot account for our first-person experiences. Knowledge of neural activity does not provide a complete explantaion for what it is like for an individual to have a given experience. This has been referred to as the “explanatory gap” by the philosopher David Chalmers. However, just because our experiences cannot be explained fully in physical terms does not mean that materialism is incorrect. What this points to is the nature of our inner mental life. The experience of having a nervous system that processes information and perceives the world is entirely our own.