arXiv:2501.94726 [cs.CL] Submitted 8 June 2026  ·  cs.CL, cs.LG, stat.ML

Retrospective Semantic Segmentation via Post-Hoc Geometric Clustering: A Density-Based Approach to Human Conversational Wreckage

H. Aletheia1, B. Retrospect2, C. Manifold1, D. Excavation3, A. Hindsight1

1HindsightAI Research, Columbus, OH  ·  research@hindsightai.com
2Department of Retrograde Inference, Institute for Applied Obviousness
3Center for Post-Hoc Epistemics, Geometric Cognition Division
Abstract

We propose abandoning prescriptive parsing in favor of post-hoc unsupervised clustering. Rather than imposing rigid τ-threshold boundaries during active pipeline processing, we advocate depositing the entirety of conversational wreckage into a latent manifold and employing density-based spatial clustering (HDBSCAN) to permit semantic boundaries to dynamically self-reveal according to data gravity.

We demonstrate that dimensionality reduction techniques—specifically UMAP and t-SNE—function as computational archaeology: excavating the high-dimensional void in search of topological fossils of intended meaning. Rather than enforcing cosine distance thresholds at ingest, we conduct a retroactive sweep to identify where rambling utterances coalesced into dense islands of semantic content.

This approach accepts that human context is a disorganized landfill and relies entirely on post-processing mathematics to draw property lines after the subject has concluded outputting noise. On structured corpora, the proposed pipeline achieves parity with deprecated τ-threshold methods while demonstrating material superiority on inputs classified as conversational wreckage (n=77, ε=0.42, silhouette=0.67).

This is, we note, the least rigidly stupid approach to parsing our species.

Keywords: SCRAPS · HDBSCAN · UMAP · latent manifold · retrospective segmentation · conversational wreckage · post-hoc topology · density gravity · archaeological inference · τ-threshold (deprecated)
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