‘Unsettling Settled Facts’: A Talk with Professor Sir Diarmaid MacCulloch.

This evening, in a combined Harris–Forbes Lecture, Dundee University welcomed renowned church historian Sir Diarmaid MacCulloch for an evening that challenged long-held assumptions about Christianity, sexuality and doctrine.

MacCulloch opened his lecture with a striking declaration: “It is our business to unsettle settled facts. I’ve done it my whole life.”

Framing history as “medicine for the soul and the mind,” he argued that examining the past can challenge fear-driven narratives, particularly around issues of sexuality and identity.

A central theme of the talk was the evolving nature of Christian belief.

MacCulloch argued that there is no single, unified “Christian theology of sex,” but rather multiple, often contradictory traditions shaped by historical context.

“Christians have spent centuries arguing with each other,” he said, noting that past disputes focused on doctrines such as the Trinity and the nature of the Church, whereas modern debates centre more heavily on sexuality.

Drawing on both theology and history, he questioned the authority often attributed to scripture in modern debates.

“Jesus is the word of God, not the Bible,” he argued, urging people to reconsider how religious texts are interpreted and used.

MacCulloch also reflected on his own experiences as a gay man, acknowledging that while progress has been made, he had only later come to fully recognise the struggles faced by transgender people.

He encouraged greater openness and understanding, describing human identity as “complex” and “creative,” rather than something to be feared.

The lecture explored how attitudes to marriage and sexuality have shifted dramatically over time.

MacCulloch pointed out that early Christian teachings on divorce and marriage were often countercultural in their original context, yet have since been reinterpreted in vastly different ways across denominations.

Addressing the Church’s historical role in shaping attitudes to sex, MacCulloch did not shy away from criticism.

He described himself as “disgusted” by aspects of the Church’s past and present, particularly where its teachings have caused harm to individuals.

The talk concluded with a call for a more dynamic approach to theology; one that responds to changing social realities while remaining in conversation with tradition.

Rather than fixed doctrines, MacCulloch suggested that Christian belief has always evolved in response to the world around it.

The event was met with strong praise.

Interim-Principal Professor Nigel Seaton described the lecture as a “tour de force,” noting he had “learnt more in the last hour than in many hours” of his life.

The talk was intriguing, thought-provoking and surprisingly funny. A memorable evening, where a lot was learned.

Crucially, MacCulloch stressed the importance of asking questions, investigating, and being critical of things as they appear.