2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/143208We present a short and intuitive argument explaining why gravity is non-renormalizable. The argument is based on black-hole domination of the high energy spectrum of gravity and not on the standard perturbative irrelevance of the gravitational coupling. This is a pedagogical note, containing textbook material that is widely appreciated by experts and is by no means original.10 pages, 4 figures, Latex. V2: typos corrected, some emphasis and clarifications addedHigh Energy Physics - TheoryGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext