01 — What Theosis Is

Theosis is the participation of the whole human person in the life of God, so that the creature becomes by grace what Christ is by nature — really god, never God. This section fixes the definition and the vocabulary, states precisely what the word claims and what it refuses to claim, and traces the “exchange formula” from its earliest form in St. Irenaeus to its most famous statement in St. Athanasius’ On the Incarnation 54.

Tradition: Pan-Orthodox

Contents

File Description
the-definition-and-the-vocabulary.md The Greek family of terms (theosis, theopoiesis, theiosis), the working definition, the “by grace / by nature” asymmetry, and the four things the word does not assert
the-exchange-formula.md The admirabile commercium — Irenaeus’ earlier form, Athanasius’ On the Incarnation 54.3 quoted exactly, Gregory the Theologian’s version, and why the formula is an argument rather than an epigram

Reading Order

Begin with the-definition-and-the-vocabulary.md to fix the terms, then the-exchange-formula.md for the sentence in which the whole doctrine is compressed and for the Christological argument it carries.

See Also