Life Exists Through Boundaries

Life does not exist by severing its relations with the external world. For example, cells distinguish their interior from their exterior through the cell membrane, while taking in necessary substances and expelling unwanted ones to maintain the conditions required for life processes. The cell membrane functions not merely as a partition but as a boundary that regulates the movement of substances into and out of the cell. Focusing on these boundary functions of life, this paper understands a boundary as a regulatory structure that enables both self-maintenance and external connection. It further examines these functions in relation to systems at different scales, including cells, organisms, interpersonal relationships, social institutions, states, artificial intelligence, and civilizations, to consider whether they can provide a shared perspective on the sustainability of complex systems. The central proposal of this paper is to shift from a binary choice between eliminating and strengthening boundaries to the question of how boundaries should be designed, operated, and updated. What matters in this regard is how boundaries function: what they allow through, what they block, who determines the conditions, and how those conditions can be changed or corrected. The disappearance of boundaries does not in itself signify progress. Might the long-term sustainability of societies and civilizations instead depend on boundary design that enables distinct entities to retain their independence, connect as needed, and contain adverse effects and recover when problems arise?