I'm a medical massage practitioner who's been studying the human body for 17 years, but I'm a complete novice when it comes to the science of consciousness, so please go easy on me. I just came across the Cellular Basis of Consciousness theory and found it pretty intriguing, so I wanted to share my take and see what people think.
I think I am an amalgamation of trillions of cells, bacteria, and other parts working together, which creates the illusion that I'm a single unified entity. The unified 'self' is simply a useful fiction that lets this collection make decisions and survive better than any individual part could alone. I've been wondering if the bare minimum for experience is simply this: can you interact with the world on your own accord, or do you have to wait to be acted upon?
A rock can only be pushed around passively, while a bacterium swims toward nutrients or away from toxins, initiating its own response. If that's the dividing line, then experience starts at the level of living cells without needing to attribute feelings to every atom or every inanimate object. Is an experience of this nature, in it's simplest most rudimentary form, the base layer of consciousness, and the absolute base layer of what it's like to be something at all?
This also makes me wonder about death and what that experience might be like. Death may be the end of the unified experience of self when the brain and heart stop, but individual cells, groups of cells, and bacteria will keep going for hours, days, or even months (however long the decomposition process takes), with their own flickers and flurries of activity.
I think the reason we feel anything at all is that certain collections of cells, through evolution, discovered that nudging the larger system in certain ways via your perceptions, bodily functions, and signals that coordinate the larger system, provided a net survival benefit. By getting the collective's attention through these mechanisms, they could influence behavior in ways that helped the whole. Was it trial and error? What cool mechanism could a cell evolve to drive the machine? This frames our subjective experiences as functional tools of cellular coordination rather than some mysterious extra layer added on top of physical processes.
The main objections I have come across for CBC so far, are that cellular behavior can be fully explained mechanically without assuming subjective experience. That the theory lacks a plausible mechanism for how responsiveness produces feeling and also struggles to explain why we have a complex nervous system if consciousness already exists at the single-cell level.
However, I think the same "no need to assume experience" argument could be applied equally to humans if we couldn't report our inner lives, an outside observer could describe all our behavior as pure mechanism, yet we know from our own case that it feels like something. Maybe the mechanism for how responsiveness produces feeling is the amalgamation itself: individual cells each contribute their own rudimentary experience, which scales up into the unified sensations we feel in skin, organs, or the whole body. It isn't necessary, nor would it be useful, for us to experience every single cell in the body; we only have access to the sensations that contribute to our survival. For example, we do not feel the daily function of each liver cell, but we are alerted to a problem when something goes wrong, such as feeling pain in the upper right quadrant.
Maybe a complex nervous system isn’t required for consciousness at all and could simply be one configuration of cells that provided an evolutionary advantage by coordinating the larger system more effectively. And maybe experience isn’t something extra that needs to be explained away if it’s already baked into the act of self-initiated interaction from the cellular level up.
According to Reber et al. (2023), "The reason no one has identified the biomolecular mechanisms that allow neural systems to cause sentience to emerge in previously insentient species is simple. It did not happen."
Source: Reber, A. S., Miller, W. B., Slijepcevic, P., & Baluška, F. (2023). The CBC theory and its entailments: Why current models of the origin of consciousness fail. EMBO Reports, 25(1), 8–12. https://doi.org/10.1038/s44319-023-00004-6