We Are The Children of LUCA
The inheritance of being is a converging point, where all branches of the tree of life lead back to the trunk of the first species, our last universal common ancestor, LUCA. This is why when I peer into the eyes of a deer or watch a bird before flight, I sense kinship — the unfolding expressions of a single lineage. Humanity is not a single expression, and if all life traces back to LUCA, what does that mean for our sense of self?
The Biology of Unity
~4 billion years ago, life as we know it began with a single cell, the Last Universal Common Ancestor (LUCA). From that quiet beginning, every living thing has descended, carrying fragments of the same ancient blueprint. The cells in our bodies are not original inventions but continuations, reshaped expressions of that first organism’s code. What we call “the self” can feel singular and separate, yet on a biological level, it is a temporary arrangement of inherited instructions, an echo of a life that never stopped dividing. The differences we cling to are illusions; beneath them, we are all extensions of the same unbroken thread.
The Self as Mirage
We are the story we tell ourselves down to our very neuroscience. The posterior cingulate cortex and related networks are the seat of self-referential thought. Memories, perceptions, and identities are all stitches in what makes a human a person and that person part of humankind. Species are not fixed points but ever-shifting branches of LUCA’s tree, and the “self” is not fixed but an ongoing construction.
The posterior cingulate cortex is central to the brain’s default mode network, the system most active when we reflect inward. It binds together memories, sensations, and self-referential thought into the feeling of a continuous “I.” Neuroscience reveals this activity as more of a construction than a truth, a stream of neural patterns masquerading as a solid self.
We inherit not just DNA but an evolved mental framework from which we find the illusion of the unified self. This illusion allows cooperation, storytelling, and society, but it also isolates us, making us feel like separate, atomized beings. In truth, we are both: unique flickers of subjectivity and inextricable fragments of a single living lineage.
LUCA’s Dynasty
Understanding our origin in LUCA and the illusions of the mind does not diminish meaning; it deepens it. To know we are children of LUCA is to recognize that our very existence is the product of 4 billion years of survival, adaptation, and resilience. Endurance is woven into our very biology just as it is in the squirrels who run along the branches of trees and the frogs who hunt for flies along the ponds edge. And to know the self is an illusion is not to erase individuality, but to see it more clearly: the boundaries we draw between “me” and “you” dissolve into something larger, a shared continuity of life.
What we inherit, then, is not only genetic memory but also the freedom to let go of the false separations that keep us small. Within the illusion of self lies the truth of connection, our kinship with everything that has ever lived, and everything still to come.
Conclusions
It is a familial bond with which I observe the doe who rests on the street of my childhood home, and not merely because we drank from the same stream as fawns. It is because we share the same family line, even if my eyes cannot look far enough back to see it. Identity is not bound within skin or species; it is a reminder that my existence is threaded through hers, and hers through mine.
