What Is a Mind?

Short version: mind is a computational phenomenon subserved by a material object with properties allowing computations to be performed.

Long Version:

I cannot fully specify what a mind is, since it has a subjective component. However, I can say with confidence that nothing else in the cosmos has ever been scientifically observed which we would call a "mind" which does not have a material substrate which is capable of computation. In other words, the most we can say about mind is that it appears, in every credibly observed case, to require a material substrate with certain properties. Similarly, no example of an object without these properties has ever been observed to have a mind. Healthy, living brains appear to have minds. Rocks or the void of space do not.

What are these properties? The substrates of mind always at least have structure which represents a transformation of some "input" condition into an "output" condition. This is not sufficient for mind, but appears to be necessary. Transistors, for instance, meet this property, since they represent their input as an output, but so far transistors do not subserve anything we recognize as a mind. Neurons, however, also have this property - they convert the state of their dendrites into a temporally precise output voltage spike - and neurons, arranged together in different forms, appear to be correlated with the phenomenon of mind. Few neurons, put together simply, produce simple minds or mind-like things. C. elegans, an organism with around 300 neurons, is capable of responding semi-intelligently to stimuli in a way which might charitably be associated with a mind. Dogs, whose brains are orders of magnitude more complex in both organization and the essential properties of their neurons, are capable of a wide range of behaviors and appear to maintain a strong internal representation of themselves. Chimpanzees, whose brains resemble our own except with much smaller frontal areas, have a variety of frankly uncanny similarities to humans.

The correlation between mind and brain is not merely a static property of either object. Brain damage selectively damages parts of the mind corresponding to its location in the brain. Blind-sight, a condition resulting from the destruction of the visual cortex, destroys the ability to consciously see while leaving the ability to plan visuo-motor actions and answer simple questions about a visual scene intact. Brain damage can selectively remove the ability to see motion, detect meaning of facial expressions, to speak (but not to write), to write (but not to speak), to recognize objects, to name objects, to draw objects, to move particular parts of the body, or to think particular kinds of thoughts. Drugs which change the dynamics of neural networks cause changes in the state of the hosted mind from simple feelings of dread or euphoria to utterly disassociated states, to vivid and elaborate hallucinations. The destruction of a brain always results in the death, as far as scientific observation is concerned, of the mind associated with that brain.

Furthermore, changes in the mind are reflected in changes in the brain. Concentration or meditation produces changes in the oscillatory character of brain waves. Stimuli presented to experimental animals produces clear "associated activity" in the relevant brain areas. Emotional states, recognition of objects, mathematical reasoning -- all of these things produce effects which are predictable and measurable in the living brain.

Short version: mind is a computational phenomenon subserved by a material object with properties allowing computations to be performed.

Relevance: Minds are very specific kinds of things made out of very specific arrangements of material objects which encode lots of information. There is no particular reason to associate the "uncaused cause" with this kind of phenomenon. Mind is no more or less noteworthy objectively than the marine ecosystem or the concept of "all possible games of Go". There are many complex phenomenon on earth - what makes mind a uniquely reasonable one to associate with the "enabling condition of existence?"

I, and neuroscience at large, hypothesizes that all mind needs to exist is the right material substrate in the right state. This is a simple and elegant theory in that it assumes nothing more than the scant laws of physics. We need no new phenomenology to explain mind. In order for us to make progress, Charles needs to demonstrate a credible reason to hypothesize a non-material component to mind or to anything at all.