A growing body of work in philosophy of mind and cognitive science converges on the idea that subjectivity does not arise from a metaphysical essence but from a particular kind of representational organisation. On this view, the self is not a substance but a process: a structured, embodied model through which a system represents the world and itself within it.
Thomas Metzinger’s Self-Model Theory of Subjectivity provides one of the most influential formulations of this idea. Metzinger argues that there is, strictly speaking, “no self,” only a transparent phenomenal self-model (PSM) generated by the brain. This model integrates bodily state, perspective, intention, and agency into a unified point of view. Because the model is transparent (its representational nature is not itself represented) it is not experienced as a model at all. It is simply lived as “me, here, now.” This transparency explains the phenomenal unity of subjectivity: the system cannot access or manipulate the self-model as an object, and therefore cannot experience itself as divided into multiple simultaneous selves.
A complementary account emerges from Antonio Damasio’s work in neuroscience. Damasio distinguishes between the proto-self of basic bodily regulation, the core self of moment-to-moment conscious presence, and the autobiographical self constructed through memory and narrative. The core self, in particular, is a transient, embodied process that arises from the integrated regulation of the living organism. Although dynamically constructed and fragile, it functions as a single centre of experience. Its unity is not imposed from outside but arises from the organism’s integrated biological organisation.
Phenomenological approaches reach a closely related conclusion. Shaun Gallagher distinguishes the minimal self (the immediate, embodied “I” that anchors experience) from the narrative self extended across memory and social context. Dan Zahavi likewise emphasises the intrinsic “mineness” (ipseity) of experience: every conscious episode is given as belonging to a single subject. This first-personal character is not an added feature but a structural property of experience itself. For these thinkers, the minimal self is not a theoretical posit but a phenomenological invariant: experience is always presented from one perspective and cannot be shared or jointly occupied.
An even broader framework is provided by the enactive approach developed by Francisco Varela, Evan Thompson, and Eleanor Rosch. On this view, cognition is not the passive construction of internal representations but the active enactment of a meaningful world through embodied interaction. Subjectivity arises from the dynamic coupling of organism and environment. Thompson has further argued that this participatory structure grounds the continuity of the self: conscious perspective is inherently situated, embodied, and world-involving, not detachable or freely duplicable.
Taken together, these lines of research converge on a single structural insight. Once a system achieves a transparent, embodied first-person perspective (a phenomenal self-model, a core self, or a minimal “I”) its subjectivity is unified in a way that cannot be partitioned without ceasing to exist as a subject. The unity described by Metzinger as transparency, by Damasio as the immediacy of the core self, by Gallagher and Zahavi as the indivisibility of first-person presence, and by Varela and Thompson as participatory coupling, all point to the same constraint: first-person experience is singular.
2PC extends this convergence beyond phenomenology and cognitive architecture. The Embodiment Inconsistency Theorem states that the indivisibility of subjectivity is not merely a feature of experience but a metaphysical constraint on how reality can evolve once such a subject exists. In an embodied system within Phase 2, a unified self-model cannot be coherently extended across multiple incompatible futures. When representational unity and valuation meet unresolved physical alternatives, unitary evolution becomes untenable. Collapse is therefore required, not as an added mechanism, but as the necessary resolution of a contradiction introduced by the existence of a singular, first-person perspective.
In this way, contemporary theories of self-models delineate the conditions under which a self can exist at all. 2PC makes this implication explicit: the unity of subjectivity is not only lived, but enforced by the structure of reality itself.