Against Heresies

Summary

Against Heresies, more fully titled The Detection and Overthrow of Knowledge Falsely So Called, is a five-book work written around 180 by Irenaeus, bishop of Lyons in Gaul. Its target is the variety of second-century movements now usually grouped as Gnosticism, especially the school of the teacher Valentinus. These groups taught that the material world was made by an ignorant or hostile lesser god, the Demiurge, and that salvation came through secret knowledge (gnosis) given to a spiritual elite. Book I sets out the Valentinian system in detail, with its heavenly beings (Aeons), the fall of Wisdom (Sophia) and the origin of the world, and then traces other teachers back to Simon Magus. Irenaeus believed that exposing these systems fully would be enough to refute them. Book II argues against them by reason, attacking the idea of a higher god above the Creator and the allegorical use of numbers. Books III to V argue from Scripture and tradition. Irenaeus appeals to the public teaching handed down in churches founded by the apostles, listing the succession of bishops at Rome from Peter and Paul to his own day. He defends four Gospels, no more and no fewer, comparing them to the four winds and the four corners of the world. He insists that the one God of the Old Testament is the Father of Jesus Christ. Irenaeus's most influential idea is recapitulation: Christ, the second Adam, sums up and renews the whole of human history, obeying where Adam disobeyed, so that humanity can grow toward the likeness of God. Mary is presented as a new Eve. Because God made matter good, he argues, the body will rise, and he ends with a vision of the renewed earth and the kingdom. The work is long and sometimes repetitive, and it was for centuries a main source for knowledge of Gnostic teaching. The discovery of Gnostic texts at Nag Hammadi in Egypt in 1945 allowed scholars to compare his reports with the movements' own writings. His arguments from apostolic succession, the rule of faith and the four Gospels became foundations of later Christian teaching.

Plot or Argument

• Book I: Exposure

  A detailed account of Valentinian teaching and a genealogy of other heretical teachers.

• Book II: Refutation by reason

  Logical arguments against a God above the Creator and against Gnostic numerology.

• Book III: Apostolic tradition

  The public teaching of the apostolic churches, the succession of Roman bishops and the four Gospels.

• Book IV: One God in both Testaments

  The words of Christ show that the God of the Law and the Prophets is his Father.

• Book V: Resurrection and the kingdom

  Christ's recapitulation of humanity, the resurrection of the flesh and the coming kingdom.

Lessons

• Public truth versus secret knowledge

  Irenaeus argues that the apostles taught openly and that their teaching can be checked in the churches they founded.

  • Why does Irenaeus distrust claims to secret teaching?
  • How do communities today decide whose interpretation of a founding text is reliable?

• The goodness of creation

  Against teachers who despised matter, Irenaeus defends the body and the created world as God's work.

  • What practical difference does it make whether the material world is good?
  • How does Irenaeus connect creation and resurrection?

• Tradition and Scripture together

  Irenaeus argues that the Scriptures and the teaching handed down in the churches confirm one another.

  • Why does Irenaeus think Scripture alone was not enough to settle the dispute?
  • What role does the rule of faith play in his argument?

• For the Christian reader

  Irenaeus learned the faith from Polycarp, who had known the apostle John, and he wrote to protect his flock from teachings that denied the goodness of creation and the reality of Christ's flesh. His appeal to the public teaching handed down in the churches and to the four Gospels helped shape how Christians recognized Scripture and the rule of faith.

  • Why does Irenaeus think the bodily resurrection is essential to the gospel?
  • How does Irenaeus's appeal to the apostles' public teaching guard against secret or private revelations?

Context

Christianity in the second century was diverse and had no agreed list of New Testament books. Teachers such as Valentinus, Basilides and Marcion offered alternative accounts of God and Christ, and some attracted large followings in Rome and elsewhere.

Composition

Irenaeus wrote in Greek at Lyons around 175–189, after the persecution of 177 in which his predecessor died. The full text survives in an early Latin translation, with Greek fragments preserved by later writers and parts of Books IV and V in Armenian.

Reception

The work was widely used by later writers such as Hippolytus, Tertullian and Eusebius. It remained the principal witness to Gnosticism until the Nag Hammadi discoveries of 1945, and Irenaeus is now often called the first systematic theologian of the church.

Comparisons

• Early Christian Writings: The Apostolic Fathers

  Irenaeus heard Polycarp, whose letter and martyrdom appear among the Apostolic Fathers.

• The First Apology

  Justin, whom Irenaeus read, defended the faith against pagan critics; Irenaeus turns to rivals within the Christian movement.

• On the Incarnation of the Word

  Athanasius develops Irenaeus's theme that God became what we are so that we might share his life.

• The Early Christian Creeds

  The rule of faith Irenaeus cites is an early form of the creeds collected there.

• The History of the Church

  Eusebius quotes Irenaeus extensively, including his list of Roman bishops.

• An Exact Exposition of the Orthodox Faith

  John of Damascus offers a later, calmer summary of the orthodox faith that Irenaeus defended in controversy.

Quotes

For Students

A reading companion for classical Christian high school students. See the student guide.

Reading Guide

Watch for

• The detailed description of Valentinian beliefs in Book I.
• The list of Roman bishops in Book III, chapter 3.
• The argument for four Gospels in Book III, chapter 11.
• The idea of recapitulation and Mary as the new Eve.

Key terms and names

Gnosticism

Modern label for second-century movements teaching salvation by secret knowledge and a lesser creator god.

Demiurge

The craftsman god who, in Gnostic teaching, made the material world.

Recapitulation

Christ's summing up and renewing of humanity's story as the new Adam.

Rule of faith

A summary of core beliefs handed down in the churches, close to later creeds.

Seminar Questions

1. Comprehension What did the Valentinians teach about the creator of the world?
2. Comprehension Why does Irenaeus list the bishops of Rome?
3. Interpretation How convincing is Irenaeus's argument for four Gospels?
4. Interpretation Why does Irenaeus think a good creation implies the resurrection of the body?
5. Big Question Should truth be open to everyone, or are some truths rightly reserved for a few?
6. Big Question Why do disagreements about the meaning of a shared text so often divide communities?

Faith Connections

• 1 Timothy 6:20 (Scripture)

  Paul's warning against 'science [knowledge] falsely so called' gives the work its full title.

• Romans 5:12-19 (Scripture)

  Adam and Christ as the two heads of humanity, the root of recapitulation.

• Nag Hammadi library (1945 discovery) (Great Conversation)

  Gnostic texts found in Egypt let readers test Irenaeus's reports.

Logic and Rhetoric

Central argument: The one God who made the good material world is the Father of Jesus Christ; the true faith is the public teaching of the apostolic churches, and Christ renews humanity so that it can share God's life.

Rhetorical device: reductio. Irenaeus restates his opponents' systems in full detail so that their complexity will appear self-refuting.

Debate: Resolved: that apostolic succession is a reliable test of true teaching.

Memory Work

For the glory of God is a living man; and the life of man consists in beholding God.

our Lord Jesus Christ, who did, through His transcendent love, become what we are, that He might bring us to be even what He is Himself

Writing Prompts

Essay: Explain Irenaeus's objections to Gnostic teaching and assess which is strongest: the argument from reason, from tradition or from Scripture.

Comparison with On the Incarnation of the Word: Compare Irenaeus's recapitulation with Athanasius's account of why the Word became flesh.

Creative Prompts

• Classroom

  Make a two-column chart comparing what the Valentinians taught (Book I) with Irenaeus's answers (Books III–V) on God, creation, Christ and salvation.

• Fiction

  Write a short speech by Irenaeus to the church at Lyons explaining in plain words why secret knowledge is not needed for salvation.

• Classroom

  Prepare a one-page handout explaining recapitulation with a diagram comparing Adam and Christ.

Further Reading

• On the Apostolic Preaching, Irenaeus of Lyons

  A shorter summary of the faith, surviving in Armenian.

• The History of the Church, Eusebius