The metaphysics of quality (MOQ) is a theory of reality introduced in Pirsig's philosophical novel Zen and the Art of Motorcycle Maintenance (1974) and expanded in Lila: An Inquiry into Morals (1991). The MOQ incorporates facets of East Asian philosophy, Pragmatism, the work of F. S. C. Northrop and Indigenous American philosophy. Pirsig argues that the MOQ is a better lens through which to view reality than the traditional dualistic subjective/objective mindset.
"Quality", or "value" as described by Pirsig, cannot be defined because it empirically precedes any intellectual constructions. It is the "knife-edge" of experience, known to all. "What distinguishes good and bad writing? Do we need to ask this question of Lysias or anyone else who ever did write anything?" (Plato's Phaedrus, 258d). Likening it with the Tao, Pirsig believes that Quality is the fundamental force in the universe stimulating everything from atoms to animals to evolve and incorporate ever greater levels of Quality. According to the MOQ, everything (including mind, ideas and matter) is a product and a result of Quality.