Henology (prefix hen, from Greek, for "one" or "unity") is the philosophical account or discourse on "The One" that appears most notably in the philosophy of Plotinus.[1] Reiner Schürmann describes it as a "metaphysics of radical transcendence" that extends beyond being and intellection.[2] It can be contrasted with ontology, as ontology is "an account of being" whereas henology is an "account of unity."
Henology stands in contradistinction to several other philosophical disciplines. The term "henology" distinguishes the discipline that concerns The One, as in the philosophies of Plato and Plotinus, from disciplines that concern Being (as in Aristotle and Aquinas) and also from those that seek to understand Knowledge and Truth (as in Kant and Descartes).[3]