Liminal Spaces

The cell exists in a liminal space, not fully alive or simply part of the non-living background of reality. The cell hasn't yet crossed over into full, realized life. It was there at one point, but it's not there yet. The cell exists in a state of ambiguity, between the known and the unknown, between reality and perception. The cell's undefined existence is clarified by its ability to perceive the external world. These "sensors" act as a bridge, connecting the cell to the environment and providing the raw data necessary for understanding its place within it. The act of sensing provides context and meaning to the cell's existence.



The continuous influx of sensory information leads to a critical mass, a point where the cell becomes aware of itself as distinct from its surroundings. The sensory input isn't merely processed, but fundamentally shapes the cell's being. The accumulation of sensory input data allows the cell to construct a model of itself and its relationship to the external world, thus achieving self-awareness. Self-perception is not an inherent property but an emergent one, arising from the interaction between the entity and its environment.



The cell transitions from a pre-life state to a self-aware state through the accumulation of sensory information. The interaction with the environment is important as a catalyst for the emergence of self-perception and, ultimately, life itself. The cell as a threshold entity found a liminal vision of life at its smallest scale. On one side lies raw, unprocessed reality—an external environment teeming with signals, energies, and potential threats or nutrients. On the other side, life itself takes shape in the cell’s internal processes, its ongoing biochemical chain reactions that define “being alive.” The cell membrane becomes a physical and biological boundary between these two realms, both protecting the cell and posing the dilemma: how to remain distinct yet responsive.



By acquiring sensors—whether receptor proteins or chemical channels—the cell transforms its protective barrier into a point of contact with the outside. These sensors distill complex external information into usable internal signals, allowing a rudimentary form of “awareness.” Over time, the cell’s continual interplay with its environment—receiving, interpreting, and responding to stimuli—cultivates a self-referential framework. In other words, the accumulation of sensory inputs gradually forges a sense of interior “self,” where the cell must differentiate what comes from outside (signals, nutrients, or hazards) from its own internal milieu. This fundamental capacity to sense and respond is arguably the seed of self-perception.



A pivotal event in the journey from mere existence to life was the development of sensors, enabling the transmission of external information into the cell's interior. These sensory inputs, carrying data about the environment, were transformed into biochemical signals, initiating a cascade of events within the cell. As these signals were processed and integrated, a remarkable phenomenon emerged: self-perception. Cells became capable of sensing and responding to their surroundings, adapting and evolving in response to environmental cues. This newfound awareness paved the way for more complex life forms, characterized by an ever-increasing capacity for sensation, integration, and adaptation.



In essence, the advent of cellular sensing and self-perception was a critical turning point in the evolution of life. This transition from a passive existence to an active, responsive, and self-aware state has had profound implications for the development and diversification of life on Earth.

 
 

Recommended reading

 
 
Nature. 2015 Jul 9; 523(7559): 204-7. doi: 10.1038/nature14593. Epub 2015 Jul 1.
Eye-like ocelloids are built from different endosymbiotically acquired components
Gregory S Gavelis 1, Shiho Hayakawa 2, Richard A White 3rd 3, Takashi Gojobori 4, Curtis A Suttle 5, Patrick J Keeling 6, Brian S Leander 7
Affiliations Expand
PMID: 26131935 DOI: 10.1038/nature14593
https://pubmed.ncbi.nlm.nih.gov/26131935/

Eye-like ocelloids are built from different endosymbiotically acquired components - PubMed

 


Tiny plankton has humanlike eye
https://www.science.org/content/article/tiny-plankton-has-humanlike-eye

 
 


Plastid-associated galactolipid composition in eyespot-containing
dinoflagellates: a review
Jori E. Graeff, Lindsey C. Elkins and Jeffrey D. Leblond*
Department of Biology, Middle Tennessee State University, P.O. Box 60, Murfreesboro, TN 37132, USA
https://www.e-algae.org/upload/pdf/algae-2021-36-5-25.pdf




 How does information of the environment enter a memory system? Information within a specific sensory modality is briefly stored in the sensory memory [12]. The sensory memory recognizes material through specific receptors for ultra-short storage of information. The sensory memory is the interface between perception and memory [12].
 
 https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/sensory-memory