Arthur S. Reber is an interesting character. He is best known in academic circles for theories of implicit learning. He has also written several books on gambling with a view to maximizing gains and minimizing losses. He has written one of the most concise and direct refutations of parapsychology which argues that we don’t even need to look at the studies or the data of parapsychologists to know the field is worthless. He has written a novel. He has also put forward a novel theory of consciousness called the Cellular Basis of Consciousness (CBC). While he has presented this at length in a book (which I currently have on order), I will talk here about a short paper that presents a more abbreviated version of the theory and is also accessible to anyone.
The paper Sentience and Consciousness in Single Cells: How the First Minds Emerged in Unicellular Species argues that the “cellular nature of life is inherently linked with consciousness”. The argument echoes Rodolfo Llinás’s position in I of the Vortex that I wrote about a few months ago. To quote from the paper:
From the CBC perspective, awareness of self and the capacity to detect, interpret, and experience the valenced characteristics of the environment is essential for survival and evolution. Environments are in constant flux. The concentration of the nutrients in the surrounding medium shifts; temperature gradients change; there is an unrelenting assault from viruses, toxins, predators – and, furthermore, these conditions are continuously changing. Without an internal, subjective awareness of these changes, without being able to make decisions about where to move, how to modify gene-expression adaptively for shifts in nutrient levels, how to match the ambient temperature with a memory of what it was in a previous location for adaptive movement, a prokaryote would be a Darwinian dead-end. Moreover, all cellular life, starting with unicellular organisms, is sensitive to anesthetics and, importantly in this respect, plants and several unicellular organisms generate endogenous anesthetics when they are wounded or stressed. In the classic model, a nonsentient agent, one lacking sensations and awareness of its environment should not be responsive to anesthetics.
Reber and his co-author Frantisek Baluska doesn’t leave the argument at that. Instead, they identify the actual biomechanisms that might be responsible for sentience that “operate at the level of prokaryotes” and “will carry on their functions in eukaryotes and multicellular organisms”. Sentience arose as a adaptive function with the first cellular life and has been conserved and elaborated as more complex organisms have evolved.
The mechanisms they identify are excitable membranes; excitable and vibrating microtubules and actin; and biological quasicrystals with the five-fold symmetry. Text below are quotes from paper.
These structural characteristics of cells are general and ubiquitous and emerging as the most likely sources of cellular awareness. Their relevance is emphasized by noting that diverse anaesthetics, ones that produce loss of consciousness in humans, also cause loss of responsiveness in all animals and plants.
Vibrating and excitable cytoskeletal polymers
A second possible source of sentience and consciousness at the cellular level is the dynamic cytoskeleton. Microtubules are regarded as important in this respect, and terahertz oscillations in tubulin have also been found to be affected by exposure to anesthetics Besides microtubules, the actin filaments behave as an excitable medium that, in addition to transporting vesicles and organelles, also transports ionic waves. Dynamic actin cytoskeleton also supports lipid rafts, which are highly ordered domains of excitable membranes that are particularly sensitive to diverse anesthetics.
Biological quasicrystals with the five-fold symmetry
Finally, there are indications that special proteins, in particular those having five-fold symmetries and quasicrystal properties, are relevant for the cellular and subcellular levels of sentience. In this respect, it is important to recognize that the three-dimensional structure of proteins is not dictated solely by the sequence of amino acids; proteins dynamically select one of several possible conformations according to physico-chemical conditions. This flexible behaviour of proteins suggests that proteins also contribute to subjectivity within single cells.
A key question would be how these components join together in larger forms to create the more complex consciousness we associate with multicellular organisms. The authors point out that these amalgamation of components actually begins quite far back in evolutionary history. Indeed, the “eukaryotic cell… is, in fact, a consortium of several prokaryotic cells transformed into the cytoplasm, mitochondria, plastids and perhaps also nuclei”. I might add that neurons themselves seem to represent a specialized sort of reactive cell. They are, however, one step removed from direct reaction to the environment. They react, instead, to sensor cells or other neurons. Their structures consist largely of excitable membranes and microtubules. The central nervous system with its brain is mass of cells is a sort of ecosystem of its own that reacts to the cells that react to the environment or its own cells.
Reber’s approach is to view consciousness on a continuum, characterized by ability to react in an adaptive manner to the environment. In a sense, the most straightforward definition of consciousness applies: ability to sense, move, and react. The fact that anesthetics affect organisms from the simplest to the most complex in the same fashion becomes the key indicator of their consciousness. The approach is also a corrective against the Homo sapiens orientation of much research which is described below.
It invited two lines of research that yielded fascinating insights into the cognitive functions of a variety of species but have had little impact on the core issue. One approach attempted to identify the neural correlates in humans responsible for consciousness and examine the evolutionary tree for evidence of those structures or homologues of them. The other sought to identify the cognitive and/or behavioural functions that were deemed diagnostic of consciousness and then look for the point(s) in the evolutionary scheme of things where species with the appropriate behaviours first appeared. We have no problems with either branch of research, but it is unlikely in the extreme that either strategy is going to get at the underlying issues: the co-terminous nature of life endowed with sentience and a theory of the initial emergence of consciousness on this planet. As one of us outlined, the field is awash with squabbles over which species have the right biological structures to support consciousness, which behavioural functions are diagnostic of awareness, where in the great panoply of life an unambiguous sentience emerged – and little progress has been made.