Mind is usually considered that part of a person that allows a unified conscious awareness of the world, our bodies, and experiences, including thinking and feeling.
Since mind seems to depend upon molecular activity in cells and in brain circuits, scientists generally assume that mind is created by, or emerges from the cells and the circuits of the brain.
Another view is that the mind uses or interacts with cells and brain circuits like a driver would use a vehicle
Since no one has been able to explain what a subjective experience is, and how it relates to the brain, all theories about the nature of the mind are speculative.
Theory 1: The Mind’s Network
As the monumental complexity of the brain emerges, the mind can be thought of as a characteristic of the network of neurons, sometimes called the “connectome”. Many local regions of brain sometimes referred to as modules (which control specific processes like vision) have extreme internal connectivity. See recent book review in Nature about mapping these 100 trillion neural connections.
Unified subjective experience, in this model, depends upon long-range connections between many modules. Recently, researchers found multiple regions of the brain where there is both massive local processing and massive long-range communicating at the same time. This implies that all of these local centers are involved in very complex cognitive and behavioral tasks—making a case for the unified subjective experience more difficult.
Theory 2: Mind as Electrical Brain Wave
Brain electrical oscillations are also enormously complex, and widespread. Since scientists cannot measure the rhythms of individual neurons in human brains, they measure millions or billions of oscillating cells at the same time.
For years, attempts have been made to correlate the different types of oscillations to different aspects of mind. See very recent work correlating short term memory with synchronized “theta rhythms” in two distinct brain regions. In one prominent theory the “gamma rhythm” is called the “neural correlate of consciousness.” This specific frequency is assumed to connect wide-ranging areas of the brain, causing all these regions to oscillate together. This, in turn, could correlate with our unified sense of subjective experience. However, this view does not offer any mechanism as to how this creates unified subjective experience.
Theory 3: Mind as Electromagnetic Field
A recent, broader view of electrical activity as the source of the mind considers the electromagnetic field as the physical structure of mind.
Theory 4: Mind as Computer
Another view of mind is that the brain is an extremely advanced computer that calculates all aspects of experience including cognition and emotion. Recently, the more advanced theory of quantum computing as a brain mechanism might allow for possibilities of free will. One prominent theory of quantum effects and mind is that of quantum computing in the microtubules of the neuron, which would increase the brain’s computing power by an incalculable amount.
Theory 5: Extended Mind
The “extended mind” theories observe mind interacting with the body, the environment and society. It is hard to imagine how our larger intellectual culture, including major ideas of science, literature and philosophy, could be explained by a mechanism of one brain. Mind appears to be based upon multiple interactions between many different people. Perhaps multiple brains connect in the same way our personal computers merge into one large, cohesive “internet” network.
Another extended theory of mind is that of an integrated flow of information. With increasing parallels between physical, biological and mental information, mathematical formulations of this information flowing at different levels could possibly be developed. In Christof Koch’s recent view integrated information, as consciousness, could also be a fundamental aspect of nature, not an emergent property. This could explain different versions of consciousness throughout nature.
The mind works through cells, brains, molecules and electromagnetism. These either create it, or channel it. But, the combined intellectual achievement of human culture seems to be so much more.
Is it possible that any of these current theories of mind can explain unified subjective experience?