Gnosticism

Overview

• Gnosticism was a 2nd-century movement claiming salvation through secret knowledge (Greek gnosis), taught by figures like Valentinus. The Church rejected it — the faith was handed down openly to all, not whispered to an elite.

Summary

Gnosticism was a family of teachers and sects that flourished in the mid-2nd century, holding that a select few are saved by possessing hidden, esoteric knowledge (gnosis) — often paired with a dualism that despised the material world as the botched work of a lesser god, and denied that the true God could take real flesh. Its best-known teacher was Valentinus; the related teacher Marcion rejected the Old Testament and its Creator God.

The Church's great answer came from St. Irenaeus of Lyons, whose Against Heresies (c. 180) both catalogued and refuted the movement, and from Tertullian's Prescription Against Heretics.

Who and When

Mid-second century, centred in Rome and the eastern Mediterranean. Principal figures include Valentinus and, in a related current, Marcion. Gnosticism was one of three unorthodox movements dividing 2nd-century Roman Christianity, alongside Montanism and Marcionism.

What They Taught — and Why the Church Rejected It

Gnosticism was, in Irenaeus' account, "predicated on the existence of hidden knowledge." Irenaeus Its teachers claimed to hold secret teachings of Jesus, passed privately to initiates rather than proclaimed publicly. Against this, Irenaeus argued that the true faith is the same faith Jesus gave the apostles — public, handed down through the succession of bishops, and open to all — not a secret reserved for the few. Because Gnostic dualism also disparaged the body and creation, it undercut the Incarnation and the goodness of a world God called "good."

The Orthodox Correction

Salvation is not escape from matter through secret knowledge, but the healing and deification of the whole person — body and soul — through Christ, who truly took flesh. The truth is catholic: proclaimed openly to everyone and guarded by the visible, apostolic Church.

Sources

• OrthodoxWiki, Heresy (Gnosticism among the mid-2nd-century movements; "predicated on the existence of hidden knowledge"; Irenaeus' Against Heresies c. 180 and the Apostolic-Succession argument; Tertullian's Prescription Against Heretics).
• See also Irenaeus, Tertullian, Montanism, Apostolic Succession, The Incarnation.