The Strongest Case for Christianity

Christian teachers have argued for their faith in many ways, and they do not all rank the arguments the same way. Some, like Thomas Aquinas (1225 to 1274), build a case from reason and the natural world.¹² Others, like John Calvin (1509 to 1564), hold that arguments for the Bible's authority work only in subordination to the inward witness of the Holy Spirit, as secondary helps to our weakness³.⁴ This page covers the Nicene core shared by Catholic, Orthodox, and Protestant churches. Where a source speaks for one branch, the page names it. For how the branches differ, see the Branches page.

Five reasons Christian thinkers give

1. A world that points to its Creator

Christian teachers argue that the world cannot explain itself. The Catholic theologian Thomas Aquinas set out five ways to show that God exists. The first three begin with things anyone can see: things change, things have causes, and things exist that might not have existed. Each, he argues, depends on something else, and the chain cannot run back forever. From change, he concludes that there must be a first mover, moved by no other, and this everyone understands to be God². His fifth way begins with order: things without minds still act toward goals, as an arrow flies to its mark because an archer aimed it.²

John of Damascus (about 676 to between 754 and 787), a monk, makes a similar case. His summary of doctrine, An Exposition of the Orthodox Faith, has long carried weight with theologians of East and West.⁵ Everything created can change, he writes, and what changes must have a maker who is uncreated and unchanging. The lasting union of opposites such as fire and water, he adds, points to a power that holds the world together.⁶

The Protestant theologian John Calvin gave a chapter to the knowledge of God shown in the making and governing of the world.⁷ The Catholic Catechism teaches that the world and humans hold neither their first cause nor their final end within themselves.⁸ Aquinas cites Paul in support²: For the invisible things of him since the creation of the world are clearly seen, being perceived through the things that are made (Romans 1:20)⁹.

Not every Christian accepts this approach. The twentieth-century Reformed theologian Karl Barth opposed natural theology, the project of arguing for God from reason and nature alone.¹⁰

2. The moral law within

Christian teachers argue that the human sense of right and wrong is a clue to the meaning of the universe. C. S. Lewis made this case in Mere Christianity (1952), a book drawn from his radio talks for the BBC during the Second World War.¹¹¹² He titled its first part Right and Wrong as a Clue to the Meaning of the Universe¹².

Lewis holds that people share a real standard of right conduct. It is not just a herd instinct, he argues, because it judges between our instincts. Hearing a cry for help, we feel a wish to help and a wish to stay safe. Something else tells us which to follow. The Moral Law tells us the tune we have to play: our instincts are merely the keys.¹²

Nor is the moral law only a social custom, Lewis argues. We learn it from parents and teachers, as we learn arithmetic, but some things we learn are real truths. When we call one society's morals better than another's, we measure both against a standard that exists apart from what anyone thinks.¹²

Catholic teaching makes a related point. The Catechism names a person's sense of moral goodness and the voice of conscience among the traits through which people come to ask whether God exists.⁸ Orthodox teaching points the same way. Thomas Hopko (1939 to 2015), an Orthodox priest and professor of theology, wrote a teaching series that the Orthodox Church in America presents on its website. In it he writes that the commands to love God and neighbor are written on human hearts and given by nature itself, citing Paul's letter to the Romans.¹³¹⁴

3. The resurrection of Jesus

Christians across the branches hold that Jesus truly rose from the dead. The Catholic Catechism calls the resurrection the crowning truth of faith in Christ.¹⁵ Lutheran teaching holds that he truly rose again the third day, and the Reformed Westminster Confession says he rose with the same body in which he suffered.¹⁶¹⁷

Hopko writes that Orthodox teaching holds to an actual resurrection, though not a simple bodily resuscitation: the risen Jesus lives in a new and glorious form.¹⁸ Paul wrote: If Christ has not been raised, then our preaching is in vain and your faith also is in vain. (1 Corinthians 15:14)⁹ In Orthodox churches, the Paschal Sermon of John Chrysostom (about 347 to 407) is read at the Easter service of Matins.¹⁹²⁰ Near its close it proclaims: Christ is risen, and life reigns.²⁰

The Catechism builds the argument in steps. The empty tomb comes first, though in itself it is not a direct proof. Then come the appearances: to the women, to Peter, to the Twelve, and, Paul writes, to more than five hundred people at once. Last comes the change in the disciples. The Gospels show them sad, frightened, and slow to believe. So, the Catechism argues, the idea that their faith created the story of the resurrection does not hold up. Their faith grew from their direct experience of the risen Jesus.¹⁵

The New Testament scholar N. T. Wright makes a historian's version of the case. In a lecture published in 1998 he argues that only the bodily resurrection of Jesus can explain how Christianity began, and that the historian has no other solution to the historical problem than to conclude that something remarkable had happened to the body of Jesus²¹.

Historians' views: see the History page.

4. Prophecy fulfilled

Christian teachers read the Old Testament as foretelling the Messiah, and they hold that Jesus fulfilled those prophecies. Athanasius (about 296 to 373), bishop of Alexandria, collected them in On the Incarnation.²² He points to Isaiah's words about a virgin who would bear a son called Emmanuel, and to passages he reads as foretelling the cross. Daniel, he argues, even foretells the exact time. He adds two signs from history: prophecy ceased in Israel and Jerusalem fell, and the nations turned to the God of Moses.²³

The French mathematician and writer Blaise Pascal (1623 to 1662) went further: The prophecies are the strongest proof of Jesus Christ.²⁴ His reasoning was that God raised up prophets over sixteen hundred years, then scattered their prophecies among the Jews. They carried the prophecies into all parts of the world, so that the Gospel could be believed everywhere.²⁵²⁴

Catholic teaching counts prophecies, with miracles, among the outward signs of revelation. The Catechism calls these signs motives of credibility²⁶, which, it teaches, show that faith is not a blind leap. Calvin, too, counted the prophets' fulfilled predictions among the proofs that Scripture comes from God.³

Historians' views: see the Sacred Texts page. For how Jewish tradition reads Isaiah, Daniel, and the other passages Christians cite, see the Judaism Sacred Texts page.

5. The Spirit's witness and the signs of the church

Some Christian teachers rank a personal reason above every argument: the inward witness of the Holy Spirit. Calvin held that arguments can silence opponents but cannot give the certainty faith needs. That certainty, he wrote, comes from a higher source than human reasons: the secret testimony of the Spirit²⁷. In his words, the testimony of the Spirit is superior to reason²⁷.

Reformed churches wrote the same view into the Westminster Confession. It lists qualities of Scripture, such as the majesty of its style and the agreement of all its parts, as arguments for its truth. Yet it holds that full assurance comes from the Holy Spirit's inward work in the heart.¹⁷

Catholic teaching joins the inward and the outward. The Catechism says God willed that outward proofs of his revelation be joined to the inward help of the Holy Spirit. Among those outward signs it counts the Catholic Church's growth and holiness, and its fruitfulness and stability.²⁶

Orthodox teaching stresses living knowledge of God. Hopko writes that the doctrine of the Trinity is not an invention of scholars. It arises, he teaches, from people's deepest experiences of God, and believers are called to pass beyond words and concepts to know God in living union with him. He sums up that union in a phrase he draws from the letter to the Ephesians: the Father, through the Son, in the Holy Spirit.²⁸

The hardest objection: why does God allow evil?

Christian teachers pose this question to themselves: if God is good and all-powerful, why is there evil? The Catholic Catechism asks it directly: If God the Father almighty, the Creator of the ordered and good world, cares for all his creatures, why does evil exist?²⁹ Aquinas lists it first among the objections to God's existence.² This page takes it as the hardest objection because Christian teachers give it sustained attention. The Catechism calls the question as pressing as it is unavoidable²⁹. John of Damascus gives it a chapter, and the philosopher Alvin Plantinga gives it a book, God, Freedom, and Evil.³⁰³¹³²

Catholic teaching holds that no quick answer will do, and that only the Christian faith as a whole answers it. God made a world still on its way to perfection, so physical evil exists alongside physical good. Moral evil comes from the free choices of angels and humans. God permits it because he respects their freedom, and he can bring good out of it.²⁹ Aquinas makes the same reply, quoting Augustine: God would not allow evil unless he could bring good even out of evil.²

John of Damascus teaches that God is not the cause of evils. When Scripture seems to say God does evil, he argues, it means God permits it, because goodness does not compel. What makes a person noble or base is the personal choice of each one³⁰.

Modern philosophers have added two answers. Plantinga's free will defense argues that it is possible any world God created with free creatures would contain some evil, so God and evil are not shown to be inconsistent.³² John Hick (1922 to 2012) drew on Irenaeus of Lyon (about 130 to about 202 CE). He argued that a world with real dangers is where people can freely grow in character and love.³³³²

Where to go next

The comparison pages set this case beside the other faiths' own accounts: Christianity vs Buddhism, Christianity vs Hinduism, Christianity vs Islam, Christianity vs Judaism, and Christianity vs Latter-day Saints. The Strongest Case book series sets each faith's strongest ground beside its hardest objection.