The book by Arthur Reber that I mentioned in my last post arrived from Amazon. I’ve read it and would like to provide some additional thoughts on my previous post. I won’t repeat ground covered in the previous post so take a look at that if you haven’t read it before reading this.
The book itself is short but it covers a lot of ground in its discussion of consciousness. At various points Searle’s Chinese room and Chalmer’s hard problem put in an appearance. Its main goal is to introduce the author’s Cellular Basis of Consciousness (CBC) theory but it places the theory in the context of the many contemporary issues and views about consciousness. CBC is quite hypothetical in that it doesn’t really have a clearly defined mechanism for sentience. It does offer the suggestion that excitable membranes that permit the flow of ions in cells might be a place to look. It also offers a possible way that the capabilities might have developed in the earliest organisms. Aside from that, CBC is mostly a proposal for how to proceed with future research on the question of consciousness. That way would be to look at the simplest organisms with a critical anthropomorphism for the indications of sentience, try to explain how those capabilities work, then examine how they have evolved in increasingly complex organisms until we end up with humans. This can be contrasted with the reverse approach, which Reber faults, of looking at the most complex brain – the human one – and trying to understand how its structures produce consciousness, then looking for analogs in simpler organisms.
As a research proposal, I think the idea is great. I have thought for a time that insects would be a great place to start to understand consciousness. Reber wants to go even simpler, back to protozoa and amoeba. The Catch-22 problem, however, is how do we know one celled creatures can be sentient if we don’t actually know what is the mechanism. Reber returns to this issue more than once responding to comments in private communication with Daniel Dennett. The issue undercuts his argument in chapter one for why robots or machines cannot be conscious. The argument essentially is that consciousness is an attribute of living beings – all living beings from simplest and earliest to the most complex – because sentience is required for surviving and thriving in complex world with ever changing conditions. Hard wiring of inflexible repertoires of responses in genes wouldn’t be sufficient or optimal. Consciousness is highly conserved as we move up in evolutionary complexity (he does, however, think that plants went down a path that might have dropped it) and it a property built directly into the wetware of the organic molecules of life. Algorithms running on silicon and copper aren’t sufficient. Metal doesn’t feel. It’s an argument I agree with but I’m not one hundred percent dogmatic about. Without a good theory of how living organisms become conscious, I can’t be sure that a robot couldn’t be conscious. I also’ can’t be persuaded a robot, even if it reproduced human behavior without flaw, is conscious without somebody providing a general mechanism for consciousness and how the robot implements the mechanism to produce its behaviors.
Reber does present some remarkable behaviors found in one celled organisms that I found surprising. They can learn. They have memories that can persist for long periods of time relative to their lifespan. They can exhibit remarkably complex behaviors that look like decision-making. They can communicate among themselves and even across species to control growth rates of collective groups. The evidence isn’t just in isolated one-off studies but across multiple studies. Is it conscious, sentient behavior, or complex fixed repertoire? We could be easily fooled.
I have generally thought to look for the first hints of consciousness in the first nervous systems. Neurons and sensory cells are the specialized cells that have evolved in many celled organisms that exhibit that same reactivity Reber identifies as sentience in single celled organisms. They do it with similar excitable membranes based on ion flows that Reber may have identified as the mechanism for the remarkable behaviors of single cell organisms. The difference is that this is the primary role of the neuron, the task it is specialized to do. Their job is to react to external stimuli in the case of sensory cells and to other neurons in case of neurons in the nervous system and the brain. They do it in groups, communicating among themselves. And that may make a big difference in whether there is sufficient critical mass to achieve sentience.
Still I’m intrigued by Reber’s idea but also wonder why not take another step with it. If sentience arose with the first life then could it be a key to understanding the origin of life? If excitable membranes are the source of sentience, might they be the critical feature that binds together the bag of chemicals that is the cell?