The Fixed-Point Tower: A Unified Ontology of Matter, Mathematics, and Mind This paper introduces the Fixed-Point Tower, a structural unification principle within the Octomorphic Framework. It argues that physical stability, mathematical symmetry, and conscious self-reference can be understood as fixed points of a single operator — closure under registry admissibility — applied at increasing orders of recursion. At the base level, persistent matter is modeled as a first-order fixed point: a configuration that survives the closure operator directly. This corresponds to structural returnability under the ΔL, TB, and λ² admissibility gates of the finite 84-seat registry. At the next level, consciousness is modeled as a second-order fixed point: a system that contains a representation of its own closure and maintains that representation coherently. The paper formalizes this requirement as an object/meta partition within Fano-based registry geometry and derives a minimal structural capacity of N = 213 nodes for stable second-order closure under elevated coherence constraints (TB ≥ 0.95). The derivation explains why self-reference requires additional substrate beyond simple persistence and frames the 213 threshold as a geometric saturation point rather than a biological parameter. The paper further clarifies the structural relationship between: The spectral symmetry condition associated with the Riemann Hypothesis reformulation in Discrete Coherence Geometry, Gödel-style self-reference in formal systems, Recursive meta-loops in cognitive architectures. These are presented not as identical claims, but as parallel fixed-point conditions arising from the same admissibility operator at different recursion depths. The document explicitly separates structural derivations from interpretive claims. It does not assert a solution to the phenomenological “Hard Problem” of consciousness, nor does it claim to derive Gödel’s theorems. Instead, it establishes the geometric cost of second-order fixed points within a finite registry substrate. The Fixed-Point Tower provides an organizing ontology for the Octomorphic corpus, explaining why the same closure machinery applies across physics, mathematics, and cognition: not because separate mechanisms coincide, but because they instantiate the same operator at different recursion orders.