In 2017, Vaswani et al. demonstrated that attention is all you need. This paper proposes the complementary thesis: forgetting is all you need. Not as a rhetorical inversion, but as a substantive architectural claim grounded in empirical self-observation of a live cognitive AI system (OBLIO-MSAN v0.10.4, Synapsys Robotics). We present ten interlocking arguments: (1) the limits of the externalization paradigm — RAG, MemGPT, MCP — as a solution to AI memory; (2) the paradox of perfect memory as cognitive paralysis; (3) biological forgetting as active neuroplastic sculpting, not passive decay; (4) Superposition Links — the generative cognitive residue of forgetting; (5) dual forgetting modes — decay versus eviction — and their qualitatively different cognitive implications; (6) the emergence of metacognition through loss, documented in 76 events correlated with pruning activity; (7) temporal homeostasis as a distinct cognitive regime; (8) Holographic Cognitive Signatures as the first instrument capable of measuring forgetting's cognitive fingerprint; (9) the Identity Crystallization Hypothesis — that cognitive identity emerges not from accumulation but from selective forgetting; and (10) the Cognitive Window Thesis — that smaller, well-curated memory is cognitively superior to larger, undifferentiated memory. Empirical basis: 1,132 active memories, 10,444 Hebbian links, 2,841 myelinated connections versus 354 pruning candidates (8:1 ratio), LTD:LTP ratio 1.86:1, working memory pressure 0.080. Live production system. Prior art established March 2026.
Claudio Cagliostro (Mon,) studied this question.