This paper develops the Dimensional Mismatch Thesis: the claim that contemporary environments no longer contain the dimensional density required for stable human development. When the dimensionality of the environment falls below the dimensionality of the developmental manifold, identity, attention, meaning, and relational coherence cannot be maintained. The resulting fragmentation is not psychological or moral in origin but a structural consequence of underconstraint.The paper traces this collapse across individual, relational, and civilizational scales, showing how low‑dimensional environments produce predictable patterns of drift, volatility, and instability. It argues that common compensatory strategies—stimulation escalation, identity intensification, relational compression, and meaning inflation—fail because they operate within the same reduced dimensionality that produced the collapse.The central claim is that coherence is a dimensional phenomenon. Stability returns only when the environment provides enough axes for the manifold to hold its shape. The paper concludes that contemporary instability is best understood as development occurring below the dimensional threshold, and that restoration of dimensionality—not optimization within collapsed environments—is the necessary condition for coherence to re‑emerge.
Denis Bailey (Sun,) studied this question.