It is impossible to understand the world without understanding religion, according to the Archbishop of Canterbury Justin Welby.

Religion needs to be seen as more than "an exercise in private piety" that needs to be covered by organisations such as the BBC in order to keep some strange people happy, he said.

"Religion is a prime motivator of behaviour for both individuals and communities."

The Archbishop was writing in this week's Radio Times about the renewal of the BBC Royal Charter this year, the constitutional document that guarantees its independence and sets out its public duties and purpose. He said that if diversity is to mean anything, it must mean more than differences in ethnicity or personal tastes.

"Despite easy assumptions of secularity, true diversity also means paying proper attention to religion," Welby continued.

"A religious commitment or worldview shapes ethical choices, political priorities, economic preferences and cultural expressions of whole societies.

"We cannot hope to understand why people do the things they do if we don't understand what drives them."

He called for "religious literacy" to be included in the new charter. "Surely there must now be a place for religious literacy in there – to improve people's understanding of the modern world."

The charter renewal White Paper, published last month, states: "The BBC should reflect the diversity of the UK both in its content and as an organisation. In doing so, the BBC should accurately and authentically represent and portray the lives of the people of the UK today, and raise awareness of the different cultures and alternative viewpoints that make up its society."

Archbishop Welby wrote: "Religion stands at the heart of any notion of diversity."

He said he backs the case made by the Sandford St Martin Trust, a charity that promotes excellence in religious broadcasting, that the promotion of religious literacy should be a specific duty for the BBC.

"For religion to be taken seriously there needs to be an improvement in religious literacy across the media," he argued.

"Religion is about the stuff of life. It's about people and communities, and what drives them. And, as has been argued before now, religion needs to be treated with the same seriousness as other genres like sport or politics, economics or drama."