Propositional Grammar and the Evolution of Personhood

The Emergence of Propositional grammar marks a genuine discontinuity in the history of mind — not a quantitative improvement on prior signaling systems, but a Phase transition into a new order of complexity. The structural key is the proposition itself: a syntactically bound claim that carries truth conditions and therefore invites epistemic challenge. Where indexical signals like alarm calls are closed, self-validating, and bound to immediate context, propositional utterances open a discursive space of justification — 'Is it? How do you know?' — that has no analogue in non-human communication.

This discursive openness has a profound consequence for the transmission of knowledge. Genetic learning is phylogenetic; individual learning is ontogenetic and dies with the organism. Propositional language introduces a third register: ontogenetically acquired knowledge that can cross the boundary of the individual nervous system, enter a shared intersubjective space, and be preserved, corrected, and accumulated across generations. Justification is the mechanism that makes this transmission reliable — it is the filter through which claims are tested before being incorporated into collective understanding.

The implications for selfhood are equally radical. The pressure to justify one's behavior to others necessitates a reflective, higher-order stance toward one's own mental states — the capacity to treat one's own intentions and desires as objects of scrutiny. This is the structural origin of Self-consciousness, distinct from mere phenomenal awareness. A tripartite architecture of the psyche follows: the pre-linguistic experiential self, the private Ego constituted through inner narrative, and the public Persona nEgotiated within the intersubjective arena of culture. Personhood, on this account, is not a biological given but an achievement of participation in normative practices of reason-giving.