Imagine a Causal Explanation of Consciousness
Is there a brain structure or a process that causes consciousness? A problem with seeking such a structure is complexity. When 100 billion neurons are firing—as they constantly do at different intervals in the brain over 1000 trillion connections or so, we cannot monitor much of what is going on. The complexity increases when we consider that neurons are signaling using countless neurotransmitter vehicles of hundreds of different kinds. Neural communication is also modulated by glia, which outnumber neurons by several times. It is becoming increasingly clear how important glia are for mental life. Note that we are just focusing on the cell level which, although low level, may not be low enough. We might have to probe beneath it to explain consciousness.
How deeply must we probe to explain consciousness? Might neuroscience, like atomic theory, come to examine ever smaller entities? Perhaps consciousness can be understood only in terms of structures smaller than the ones we have examined so far.
Imagine some distant ancestor of the Homo habilis species, trying to understand fire by poking at burning wood. Could we be as far from understanding consciousness as that ancestor was from understanding combustion?
Suppose we succeed in understanding consciousness scientifically. What would such an understanding be like? Suppose our knowledge of the brain becomes so complete that we know about all of the neurotransmitters, neuron types, glia involvement, pathways, functional localizations, and so forth. What is more, we can do something called an x1 scan, capturing the ongoing neuron firings, exchange of neurotransmitters, glial communication, and so on, in real time without delays. If an x1 scan seems crude, we may conceive of higher-precision scans, such as an x2 scan, capturing all known parts of the neurons and glia and what they are doing, or an x3 scan, pursuant to the standard model of physics. Suppose, in other words, we can scan the brain and make its structure and evolving configurations entirely perspicuous. Let us imagine further that we have a neuroscientist—Ben—who is hard at work on this new type of data.