Traditionalism, also known as the Traditionalist School, is a school of thought within perennial philosophy. Originating in the thought of René Guénon in the 20th century, it proposes that a single primordial, metaphysical truth forms the source for, and is shared by, all the major world religions. Unlike universalist forms of perennialism based on commonalities in religious experiences across cultures, Traditionalism posits a metaphysical unitary source known as Tradition which forms the basis for the major religions in their "orthodox" forms.