Everyone seems to pretty much agree that consciousness is a big mystery, and a really important one. Careers have been built, and books written, on the topic.
Of course, no one really agrees on what consciousness means. Is an animal recognizing itself in a mirror a form of consciousness? Others seem to confuse consciousness with thought. Is consciousness somehow related to emotion, such as what we feel when viewing a beautiful sunset? Is consciousness related to the elusive notion of qualia–what it means for something to be “red”, for example? Or is consciousness what distinguishes human beings from lower life forms–we are conscious, and they are not? Is consciousness merely the quality of being conscious (assuming we can define that), or something more? Is consciousness connected to, or identical with, the values we associate with humanity, such as ethics, or love, or loyalty? Is consciousness a state, or a process? Ultimately, in our discussions of consciousness we are trapped in an infinite loop: we don’t know what consciousness is, so we cannot speak coherently about it or what mechanisms it might be based on, and without knowing the mechanisms it is based on, we cannot define it.
To me, it makes no sense when talking about consciousness to say I’m conscious of having a headache. I just have a headache. It make no sense to say I’m conscious of seeing a chair. I just see a chair. It makes no sense to say I’m conscious of a beautiful sunset; it’s just a beautiful sunset. The term consciousness is vacuous if we use it to refer to any experience whatsoever. To be worth talking about, consciousness must have a subject. For purposes of this discussion, we will say that the subject is an experience. Consciousness is not merely having the experience; it is a higher-level mental process whose subject is the having of the experience. By “experience” I mean something that we think, or sense, or feel. If one chooses to consider thoughts, and senses, and feelings, as neurological processes, then by this definition consciousness is a higher-level mental process whose subject is neurological processes. Since a mental process is itself a neurological process, it follows that consciousness is best defined as a neurological process the topic of which is a neurological process. Expressing this way makes the recursive nature of consciousness clear: we are conscious, but also can be conscious of being conscious, and conscious of being conscious of being conscious, and so on ad infinitum. To make it clear, this can be called reflective consciousness.
What about unconsciousness? Some studies of consciousness concern themselves with taxonomies involving people who are in comas, or under anesthesia, or asleep. Yet these are cases in which perception itself–the experience itself–is absent, and need not concern us here. Obviously there cannot be a neurological process the topic of which is a neurological process when the underlying neurological process itself is not present.
Although cats can recognize themselves in a mirror, and can feel love, or at least behave in ways we perceive as them feeling love, we generally would not call them conscious. The cat might be hungry, and might “feel” hungry, but we would not say it perceives itself as being hungry, nor would we imagine that it is capable of any higher-level brain processes related to its self-perception of hunger. A human, on the other hand, might be hungry, and might feel hungry, but can also treat the hunger as a topic for further thought: “I wonder why I’m hungry”, or “I always feel hungry this time of day”, but also even “Every time I get hungry like I am now I wonder why I do and now I’m doing that again”. What is it that allows our race to have these kinds of meta-thoughts, which arguably is the ability that accounts for our immense success on this earth, right after the opposable thumb.
Long-time readers of this blog, especially of earlier posts about neurotheology and neuroscience, will not be surprised that our approach is a neurological one. So the question becomes, what are the neurological mechanisms that underlie reflective consciousness, and in particular, how did the human brain evolve this capability?
Let us quickly dismiss various far-fetched and unproven proposals about consciousness. One, for instance, asserts that perhaps some kind of “quantum effect” or “action at a distance” or “electron entanglement” is at work. Left unsaid is how such exotic phenomena could possibly produce reflective consciousness. Others propose that consciousness is a kind of “substance”, like “ether”, a fundamental property that somehow arises magically from networks. As much as one wants to attribute consciousness to FaceBook, this does not seem to contribute to a concrete understanding of consciousness. Then of course we have charlatans like Deepak Chopra preaching his muddled philosophy that “consciousness is the basis of all reality; reality is created by consciousness”, which seems to mean precisely nothing at all.
So how might such reflection features be implemented in the human brain? Shall we go looking for some part of the brain with handles reflective consciousness, such as the claustrum? Eminent consciousness researcher Christof Koch has compared the claustrum to the conductor of an orchestra. It has been suggested that the claustrum helps coordinate the timelines of the two sides of the brain, or that it has functions related to integrating input from various senses, to provide a “conscious experience” combining the visual, auditory and other sensory inputs of a friend you are talking to, for example. Whether or not that is the case, it’s hard to see why this useful feature would be considered related to consciousness per se; it would appear to be a matter merely of perception. We are back at the problem touched on above about the definition of consciousness.
It would seem highly implausible that the kind of consciousness that I want to talk about–let’s call it recursively reflective consciousness–could be localized to a particular part of the brain. Let us consider the process of “reasoning” about a piece of furniture, that based on its shape–four legs and a flat surface a certain distance above the ground–it is a “table”. Reasoning at this level would not usefully be considered an expression of “consciousness”. Now assume we are asked to introspect about this reasoning process; someone asks us, “Why do you think that is a table?”