Written and presented by Dr Ed Kessler MBE, founder and director of the Cambridge-based Woolf Institute, this compelling guide to religious belief and scepticism is a must-read for believers and nonbelievers alike.

Founded in 1998 to explore the relationship between religion and society, the Woolf Institute uses research and education to foster understanding between people of all beliefs with the aim of reducing prejudice and intolerance.

Says Dr Kessler: “Latest surveys suggest that 84 per cent of the world’s population identify themselves as belonging to a specific religion, and in many parts of the world the most powerful actors in civil society are religious. Understanding religion and belief, the role they play and their impact on behaviour and decision-making is, therefore, vital.”

Dr Kessler – who was awarded an MBE for services to interfaith relations in 2011 – is an affiliated lecturer with the Faculty of Divinity at Cambridge University, a principal of the Cambridge Theological Federation and additionally teaches at the Cambridge Muslim College.

He says: “This A-Z of Believing aims to show how the encounter between religions has influenced and been influenced by the evolution of civilisation and culture, both for good and for ill. I hope that a better understanding of believing will lead people to realise that while each religion is separate, they are also profoundly connected.”

A is for... Atheism

Give someone a fish and he will eat for a day; give someone a religion and he will die praying for a fish – Anon

Although atheism begins with the letter A, it may seem an odd choice with which to start an A-Z of believing. But the term has a long history. Around 2,000 years ago, at the time of the formation of Christianity, pagans condemned Christians, as well as Jews, as atheists because they rejected belief in the official gods of the Roman Empire and refused to participate in ceremonies in their honour.

In the Middle Ages, thinkers such as Aquinas (a Christian), Maimonides (a Jew) and Averroes (a Muslim) felt the need to formulate “proofs” of God’s existence – for while belief in God on the grounds of faith was assumed, there was still a need to respond to heretics with rational proof. Some medieval mystics, such as the anonymous author of The Cloud of Unknowing, argued that it was incorrect to say that God exists because existence requires a particular form within space or time. Because God has no particular form and is outside of time, God, therefore, cannot be said to exist. However, God is.

All of this demonstrates that atheism has a long and distinguished history of influencing religious thinking in a profound way. And this has continued.

Famously, Friedrich Nietzsche wrote: “God is dead. God remains dead. And we have killed him. Yet his shadow still looms.” Jewish and Christian theologians in particular reflected on this proposition, brought to public attention by Time magazine’s front cover in 1966 which asked: “Is God Dead?”. Time reported that three Christian theologians saw “the death of God” as a liberating experience, while Jewish theologian Richard Rubenstein concluded that a God of history lacked credibility after the Holocaust because the genocide had shattered a system of religious meaning that sustained Jews (and Christians) for 2,000 years.

What these theologians and others shared is the belief that to live in the time of the “death of God” is a cause of profound soul-searching. The challenge continues – and contemporary atheist thinkers such as the “Four Horsemen of Atheism” (Christopher Hitchens, Richard Dawkins, Daniel Dennett and Sam Harris), known as “evangelical atheists”, insist that non-believers can be just as moral as believers – although it may be truer to suggest they can also be as immoral as believers.

While figures today suggest that 84 per cent of the world’s population identifies with a religion, it is an exaggeration to suggest that the rejection of God represents the view of all those who have no religious affiliation. The “unaffiliated” 16 per cent, which is the third largest category in the world after Christians and Muslims, includes atheists and agnostics as well as people with spiritual beliefs but no link to any established faith, suggesting the number of atheists, excluding Buddhists, is small.

The “practical atheism” of Buddhism represents a different set of issues because unlike Christians, Jews and Muslims, Buddhists do not believe in a creator God. If atheism is the absence of belief in a God or gods, then many Buddhists are indeed atheists, for God is unnecessary. When Siddhartha Gautama became the Buddha (the “awakened one”), and woke up to life’s meaning, he saw it as human liberation into the truth of things, which required individuals to sort out their own lives, with his discovery as their guide. The fact that the gods are powerless to help, indeed, that they are dependent upon the Buddha’s insight, is a far cry from the Abrahamic perception of a God of redemption, grace and compassion.

Related to atheism is humanism, which arose during the enlightenment and affirms humanity while denying belief in God. Even here, there are examples of religions that describe themselves as humanist, meaning that they are “non-theist”, and humanist groups draw heavily on religious writings. The Society for Humanistic Judaism, for example, founded in 1969 by Rabbi Sherwin T Wine, explains that “humanistic Judaism embraces a human-centred philosophy that combines the celebration of Jewish culture and identity with an adherence to humanistic values and ideas”. Unitarian Universalists share a similar humanist commitment.

The Economist’s millennium issue returns us to the question of religion’s demise by asking: “God: After a lengthy career, the Almighty recently passed into history. Or did he?” The reader was informed that the “test will come on Judgment Day, when man, we are told, will meet his maker. Or will it be God meeting his?”

I felt some sympathy for the editor who a few years later recognised that the vast majority of the world regard God as a factor in shaping their lives and had a dramatic change of heart, publishing a book in 2008 entitled God is Back.

But I don’t think God ever went away.

Next week: B is for Beauty